I hope the iterview is much better than the marketing literature. This quote from the literature made me want to vomit...
Quote:
By bouncing sound off the walls and floors this introduces the room itself as part of the instrument of sound.
I had always thought that Geddes and most others were trying to control directivity to REDUCE the effects of the room on the sound. If Carver is going the other direction with this design (which the marketing hype indicates) I am VERY surprised.
The other thing about the marketing hype that bugs me is this:
Quote:
Sunfire created the category of small-box, high power subwoofers more than a decade ago with the original True Subwoofer. This design relies on high-pressure, High Back-emf technology which provides very high bass output from a very small box. When migrating this subwoofer technology into the midrange and high frequencies on the Cinema Ribbons, we find the same advantages: high output, small size, high efficiency, and low voice-coil heating.
While I admire the design and understand the motiviation for a small box (primarily WAF) these designs are NOT high efficiency and they do NOT reduce voice-coil heating as compared to other designs. Hoffman's iron law doesn't get broken very often .
Again all of this may be marketing hype but I have a lot of respect for Carver and had hoped his marketing would reflect the science behind his concepts. Neither of the quoted sections seem to...
I hope the iterview is much better than the marketing literature. This quote from the literature made me want to vomit...
I had always thought that Geddes and most others were trying to control directivity to REDUCE the effects of the room on the sound. If Carver is going the other direction with this design (which the marketing hype indicates) I am VERY surprised.
The other thing about the marketing hype that bugs me is this:
While I admire the design and understand the motiviation for a small box (primarily WAF) these designs are NOT high efficiency and they do NOT reduce voice-coil heating as compared to other designs. Hoffman's iron law doesn't get broken very often .
Again all of this may be marketing hype but I have a lot of respect for Carver and had hoped his marketing would reflect the science behind his concepts. Neither of the quoted sections seem to...
I agree that Carver includes a healthy dose of hyperbole in his pitch. But he didn't say that the small box increases efficiency. He said that it increases power handling and reduces voice coil heat. This is true.
A very very small box controls excursion. I have some B&C eights in a box thats barely big enough to contain the frame, and the power handling is mind boggling, because excursion is so tightly controlled. Small boxes are the hot ticket for huge midbass power handling IMHO
The voice coil heat argument is a bit trickier. When you think about it, a very small box is prone to overheating, because there's so little air in the box. But the key is that it's not ported. At the tuning frequency of a ported enclosure, the impedance drops to it's lowest point, which means that the amplifier is absolutely dumping power into the woofer.
I think this is another reason that very small sealed enclosures can tackle such abusive amounts of power, particularly if the resonant frequency is in the passband. Here's an example of this:
Picture the typical car audio setup, with a set of 170mm woofers in the door. They have a resonant frequency of 40hz, and they are crossed over at 80hz. The resonant frequency of the woofer is below the passband. Due to this, the woofer has an impedance of four ohms at 80hz, and our amplifier is dumping two hundred watts into the woofer, creating voice coil heat.
Compare this to the Carver setup. The free air resonance of the woofer is 60hz. Because it's in a very small box, the resonance is moved up to 95hz. Because the resonance is in the passband, the impedance is just eight ohms at 120hz, and our amplifer is dumping half the power into the woofer.
Hopefully that makes sense. In a nutshell, the sealed box controls excursion, and pushing the resonance of the woofer up reduces the amount of power that is getting dumped into the woofer at the low end of it's passband.
*My pics of the impedance are only for illustration. I didn't do any sims, I just posted the pics to show how the woofer's resonance moves up and down in the passband depending on the resonance, and how crossing over below the resonant frequency can increase your power handling if the excursion is kept under control.
Build a better mousetrap and the world will beat a path to your door.
Its Hoffman's Iron LAW, not Hoffman's Iron theory.
With regard to increasing power handling, its also a load of bullshit. Yes you increase power handling due to controlling cone excursion, but you consequently reduce output at a greater rate than you increase power handling, which is counterproductive.
The efficiency will suck, but amplifiers are cheap. So we have a two step process for massive output from a small woofer:
Step 1: Put the woofer in a very very very very very small box. Taken to the extreme, you literally seal off the basket of the woofer. This is what I do in my Unity horns.
Step 2: Now that you have excursion controlled by the box, you have to deal with heat. This requires two things. First, the biggest voice coil you can fit onto the woofer. Second, the sealed box pushes up the impedance of the woofer at the low end of the passband, and that can reduce the amount of power going to the woofer by half or more. (IE, it doubles your output at the low end, right where we need it.)
The woofer on the left is a 400GTI, which fits this design criteria nicely. Big ol' voice coil, lots of venting, and a small cone. That is a neodymium motor too! The biggest one I've ever seen on a midrange.
Build a better mousetrap and the world will beat a path to your door.
*GOOD* amplifiers are not cheap. Shitty power is cheap. Class D automotive is cheap. Good, distortion-free power with excellent dynamics is not cheap.
As your power requirements go up, so does your distortion. You severely limit your sound quality with a small cabinet.
I'm not saying that distortion is completely irrelevant, but it's pretty easy to fix with a big voice coil and a small box.
Distortion goes up with excursion. Because of this, a 6.5" woofer in a car door, flopping around wildly because the door leaks like a sieve, can be outperformed by a 4" woofer with high power handling in a very very small box. The box controls excursion, and that's why it sounds cleaner.
The key is keeping excursion under control.
Quote:
Originally Posted by XtremeRevolution
I understand this is the best you can do for car audio, but don't make it sound like its a great thing when its really only the best thing you can do with your requirements. When your requirement is small and compact, you do the best you can, but that's a requirement that should be stretched as much as possible.
Diffraction is a pretty big deal. That's why people in this thread are getting such excellent results with spheres.
I believe that reducing diffraction is more important that reducing distortion.
Small enclosures offer some big advantages in terms of diffraction. That's why the Carver design is exciting. Check out the reviews - people are raving about these. I think that has a lot to do with diffraction.
Build a better mousetrap and the world will beat a path to your door.
"Controlling directivity" is synonymous to destroying your off axis listening.
Quite the opposite, in fact. Controlling directivity, perhaps counterintuitively, can be used to expand the "sweet spot" into a "sweet zone.
Quote:
Originally Posted by XtremeRevolution
Proper home theater and music listening speakers are designed as such that they can be heard without any changes at any listening angle.
So you're saying it's omni or nothing?
And sadly most speakers are designed with big flare-ups of energy in the midrange, due to the directivity mismatch between a midwoofer and a flush-mounted dome tweeter at the crossover frequency. They can lock in in a small spot, but everywhere else...ewww.
Quote:
Originally Posted by XtremeRevolution
Tweeters are especially crucial to this effect due to the wavelengths of the frequencies they produce, hence the use of waveguides.
Um, waveguides control directivity...
Quote:
Originally Posted by XtremeRevolution
*GOOD* amplifiers are not cheap. Shitty power is cheap. Class D automotive is cheap. Good, distortion-free power with excellent dynamics is not cheap.
Yes it is. And plenty of those "class D automotive" amps provide your "good, distortion-free power with excellent dynamics,."
Quote:
Originally Posted by XtremeRevolution
With regard to 6.5" door drivers "flopping around," this is not something you would ever experience in home audio with the exception of an open baffle design.
Depending on levels required and highpass frequency, that's not true.
I design my speakers and the placement of the tweeters using the following baffle diffraction simulator. Feel free to play around with it some and you'll see not only a predicted baffle response, but also a suggested crossover network to flatten the response.
Quote:
Originally Posted by XtremeRevolution
"Controlling directivity" is synonymous to destroying your off axis listening.
Quite the opposite, in fact. Controlling directivity, perhaps counterintuitively, can be used to expand the "sweet spot" into a "sweet zone.
Quote:
Originally Posted by XtremeRevolution
Proper home theater and music listening speakers are designed as such that they can be heard without any changes at any listening angle.
So you're saying it's omni or nothing?
And sadly most speakers are designed with big flare-ups of energy in the midrange, due to the directivity mismatch between a midwoofer and a flush-mounted dome tweeter at the crossover frequency. They can lock in in a small spot, but everywhere else...ewww.
Quote:
Originally Posted by XtremeRevolution
Tweeters are especially crucial to this effect due to the wavelengths of the frequencies they produce, hence the use of waveguides.
Um, waveguides control directivity...
Quote:
Originally Posted by XtremeRevolution
*GOOD* amplifiers are not cheap. Shitty power is cheap. Class D automotive is cheap. Good, distortion-free power with excellent dynamics is not cheap.
Yes it is. And plenty of those "class D automotive" amps provide your "good, distortion-free power with excellent dynamics,."
I recently heard the adult-sized version of that speaker. For what it is, it's fine. But trust me, compared to the stuff PB uses daily (GedLee Summas)...well, it's barely a toy. I would go so far as to say that the gap between the little Carver things and Statements is minute compared to the gap between Statements and big controlled directivity mains.
Perhaps I misrepresented the word directivity. What I meant to say was I had heard very directional speakers. Given the way you chose to use the word, it is obvious that waveguides serve a purpose, but I'd rather say they enhance directivity. Regardless, its irrelevant.
Commonly available class D amps are inferior in regard to sq to class A and class AB amps. Class d architecture has been around for years but only recently has it started to reach fidelity levels that can be used in home theater. Don't you think there's a reason stereo car amps are not designed on a class D architecture? Also consider the testing methods used to test class AB amps cannot validly test class D amps. More on that if you're interested. Again, this was a side point, and is insignificant in comparison to the main points I made. How about you address those.
You telling me the little carver things are nearly the same as the statements tells me your completely full of shit and that you haven't heard the statements. The statements are a transmission line midrange design to eliminate midrange cabinet coloration and create a much wider sound stage using the rear opening reflection, with an extremely flat frequency response and amazing low frequency extension/impact. They rival line arrays 10x their cost in parts. Re-read hoffmans iron law till it sinks in. To also call them barely a toy is insulting at best. I know money doesn't buy performance but to spend $800+ on components alone and have you call them a toy is a real stretch. They also need to be used in the correct room size and with a capable amplifier.
Tell me real quick what speakers have you built or designed that gives you such an authority to trash talk the design of real engineers?
Sent from my HTC Awesome using Tapatalk
Build a better mousetrap and the world will beat a path to your door.
By "misrepresented" you mean "don't understand," I presume.
Quote:
Originally Posted by XtremeRevolution
Commonly available class D amps are inferior in regard to sq to class A and class AB amps.
As soon as I see idiot spew like that, I know I'm not dealing with someone who knows what s/he's talking about. Show me a single controlled listening test that supports your idiot assertion!
Quote:
Originally Posted by XtremeRevolution
You telling me the little carver things are nearly the same as the statements tells me your completely full of shit and that you haven't heard the statements.
It appears you read about as well as you think you can hear. I didn't write that. What I wrote is that the difference between the Carver jewelboxes and Statements is less than the difference between the Statements and GedLee Summas. Since you seem big on cost comparisons, for reference, just the driver complement in a single of Summas is more than the driver complement in a pair of Statements.
Quote:
Originally Posted by XtremeRevolution
The statements are a transmission line midrange design to eliminate midrange cabinet coloration and create a much wider sound stage using the rear opening reflection, with an extremely flat frequency response and amazing low frequency extension/impact. They rival line arrays 10x their cost in parts.
Cockamamie midrange tunnel aside (if it has any effect, it is merely to slightly smear the midrange - again I've heard them and you appear not to have, given that you claim to be in the "project" process) it appears that you have consumed gallons of the Kool-Aid. Enjoy your project, but you'd be wise to avoid attacking people like PB who have forgotten more than you or I together have figured out. (And done more crazy/interesting projects than most of the rest of the audio internet community combined.) It's pretty clear from your posts that you don't understand what he's writing about, anyway. (Or what I'm writing about.)
Quote:
Originally Posted by XtremeRevolution
Tell me real quick what speakers have you built or designed that gives you such an authority to trash talk the design of real engineers?
Well, I "designed" an ultra-low diffraction (>2" roundovers on the top and bottom, rounded front corners, and 2" roundovers on the sides wrapping around in a continuous curve to the back of the cabinet) sealed cabinet for my Tannoy System 12 DMT II's, and in my youth (before I learned that others do it better than I can) I probably designed and built a new pair of mains every 6-7 months.
I expected as much from you. I'm not one to leave an argument but I have no desire to argue anything with someone who resorts to personal attacks to make a point and can't even stick to the topic at hand. I'm out of here. You apparently have all the knowledge and expertise to figure everything out. Class D automotive amps are better than class AB in every concievable way, my understanding of the word directivity determines my intelligence, and because I support hoffmans law, I must be an idiot by the same regard. Surely everyone is wrong and the only way to perfect baffle diffraction is to use a sphere. Man have we all been fooled.
I understand what he's writing about, and I also have enough understanding in speaker design to know what the flaws are. What threw me off was one of the earlier posts where he compared the baffle diffraction of a sphere to that of a squared centered baffle. No mention of filters, crossovers, or baffle placement.
Surely I'm the one drinking the coolaid. I'm clearly mistaken. Let's all replace all of our speakers with spheres on sticks that we have to mortgage our houses to buy, and try to squeeze some midbass out of thin air since they're clearly superior. Forget cabinet volume, its irrelevant. Every designer in the past 100 years is wrong. Forget efficiency, its pointless. Hell, let's just go down to 80db efficiency and push 1000w through them with automotive monoblocks instead. Yeah, my alpine mrp-m1000 would be great for powering a floorstanding speaker. Oh yeah, and the guys over at denon, yamaha, pioneer, onkyo, and everyone else who sells receivers of any kind are stupid. What are they thinking, class D is so much better. Silly idiots, they should know better. If we don't have excursion, we won't have to worry about distortion. Let's just make 6.5 comps with 5" voice coils and neo magnets to handle the power. Forget frequency response, who needs to hear 90-300hz anyway. Has a response chart of these speakers' design performance even been posted yet?
Class D automotive amps are better than class AB in every concievable way,
To be clear, nobody wrote that. What was written, and what is true, is that nobody has ever shown that there is a sonic difference between a good class AB and good class D amp in a controlled listening evaluation.
Quote:
Originally Posted by XtremeRevolution
my understanding of the word directivity determines my intelligence,
Again, learn to read. Nobody has written what you claim they have. That said, your willingness to throw around technical-sounding words without understanding what they mean, followed by getting extremely defensive about it...those things together do allow reasonable people to draw some legitimate inferences about your ability to communicate in written English. Some, rightly or wrongly, consider that a reasonable proxy for intelligence.
Quote:
Originally Posted by XtremeRevolution
and because I support hoffmans law,
Please point out where anyone said anything tending to negate HIL.
How about you define HIL, for that matter. I suspect you don't quite know what that term means (either).
Quote:
Originally Posted by XtremeRevolution
Surely everyone is wrong
One should never discount that possibility entirely...
Quote:
Originally Posted by XtremeRevolution
and the only way to perfect baffle diffraction is to use a sphere.
Funny, considering you're replying to me. Where did I once mention a sphere? I take it geometry wasn't your best subject in middle school.
Quote:
Originally Posted by XtremeRevolution
Oh yeah, and the guys over at denon, yamaha, pioneer, onkyo, and everyone else who sells receivers of any kind are stupid. What are they thinking, class D is so much better. Silly idiots, they should know better.
Why don't you think before you write? It's kind of an important exercise, if one wishes to avoid looking like a fool.
Let's look at Pioneer's flagship receiver.
What kind of amplification does it use? HINT: ICEpower = Class D.
I suspect within five years the others will follow suit as well. Especially if oil stays so high. The cost advantages of smaller, lighter amps (coupled with the utter lack of sonic penalty - note that I'm not saying one is superior, only that good implementations of either are sonically indistinguishable from one another; that is not a subtle distinction) when dealing with container shiploads of the things is simply too compelling over the long term.
Quote:
Originally Posted by XtremeRevolution
If we don't have excursion, we won't have to worry about distortion. Let's just make 6.5 comps with 5" voice coils and neo magnets to handle the power.
You're missing kind of an important piece in the whole puzzle. Actually several, but I'll let you go back through and figure it out, if you can.
With regard to "Bob's" insanely small enclosure, I would LOVE to see a frequency response chart. Someone with such "revolutionary" designs must clearly have the data to back up his claims. By that regard, so should the OP. This thread is 1.5 years old yet I haven't yet seen a frequency response chart.
That's b/c the F/R plots of the compact midbass aren't in this thread, b/c this thread wasn't intended to cover that. Somewhere it got derailed.
...if you have dual climate control, that would be more likely to cause a timing issue ... Sound travels faster through warmer air so lets make sure both zones are the same temperature. lol
I put the tweeter into the aluminum stand and placed it on the dash.
The sound becomes smoother, no harsh even when I played music of chinese traditional musical instrument , and the music somelike melt in the air. Thanks Mr Bateman !
Alpine CDA-7949 + CHA S609, CDA-117E, Kenwood KEC-600, Focal 165KRX2, SS rubicon 502 for tweeter, SS rubicon 702 for woofer, SS rubicon 1002 for Alpine SWR-1243D
The efficiency will suck, but amplifiers are cheap. So we have a two step process for massive output from a small woofer:
Step 1: Put the woofer in a very very very very very small box. Taken to the extreme, you literally seal off the basket of the woofer. This is what I do in my Unity horns.
Step 2: Now that you have excursion controlled by the box, you have to deal with heat. This requires two things. First, the biggest voice coil you can fit onto the woofer. Second, the sealed box pushes up the impedance of the woofer at the low end of the passband, and that can reduce the amount of power going to the woofer by half or more. (IE, it doubles your output at the low end, right where we need it.)
Is this better than just using a high-pass crossover? Wouldn't that reduce power and excursion? Or, are you doing this in part for packaging concerns? I feel like I'm missing something here.
BTW, thanks for your contributions. I'm about halfway through reading pretty much everything at your forum, and it's fantastic!
I've been hit by one car too many, so I refuse to ride with headphones, and Parts Express sells a $20 battery powered amp that would work nicely with something like this.
Build a better mousetrap and the world will beat a path to your door.
My replies are in red.
How about you answer questions since you've proven incapable of addressing points I've made with any resemblance of decency.
1. how do you produce midbass if your goal is to limit excursion, and how do you increase output while limiting excursion? After all, the whole idea here is to make a very small enclosure because of the notion of "a 6.5 comp flapping around in a door" is somehow bad. So say we take that 6.5 and stuff it in a .05 cubic foot pillar pod and we limit its excursion. How then do we get a usable frequency response from 90-200hz? Keep in mind, it was stated that excursion produces distortion, so keeping excursion down is of paramount importance.
2. once you've explained the above, explain what the frequency response will look like without any equalization. I have yet to see a frequency response chart of
This post is also what I've been responding to:
I claimed that even though you increase power handling in a smaller enclosure, you exponentially decrease your output. You can go as far as to make said driver a sealed back driver in a very small box (which if our point is to control excursion should have been thought of by more companies than Goldwood) and I am claiming that by doing so, you are causing massive problems in the 90hz-200hz range. You *REQUIRE* excursion for low frequency extension. By nature of every loudspeaker designed in the last 50 years, you cannot hit the lower registers without excursion. The above quoted post claims to defy Hoffman's law, that you can simply put the drivers in an extremely small enclosure and pump more power into them to get the same output. What the above poster doesn't realize is that you have now created an output ceiling, and for every decrease in enclosure size, you're reducing that ceiling. If we could all get all the bass extension we ever could out of a sub box that barely fits our subs, don't you think we'd all have done it by now? Just build massive subs with 10" voice coils to handle the heat and put them in insignificantly tiny boxes. You can stretch, but you cannot defy Hoffman's Iron Law.
This discussion is a bit off-topic - the main reason I posted the Carver solution is that Carver addressed one of the problems with the spherical tweeters. Which is that they don't play low. By putting the tweeter on one face, and the woofer on the other, you get a full range solution.
As far as Hoffman's Iron Law goes, I've admitted that the efficiency of the Carver solution will be atrocious. I wouldn't be surprised if it's in the low 80s. The thing is, efficiency is completely overrated. I have seven hundred watts for each channel. Power is cheap.
I haven't heard the Sunfire speakers. I *have* heard the Gallo speakers, and the dimunitive speakers from Sony. The Gallos sound shockingly good, particularly since they use a Tang Band woofer that costs ten bucks. The Sony speakers sound "thin", but they image like crazy.
And that's what I'm getting at in this thread.
This thread isn't about deliver chest thumping bass. This thread is about imaging, and speakers that sound smooth as silk. The Gallos in particular fit that bill. Is there distortion? You betcha. Is it offensive? No, I don't think it is. It took me a few years to wrap my brain around the idea that distortion isn't the worst thing in the world. Diffraction is a bigger problem than distortion IMHO.
Not to get off-topic, but I think that car audio has been stuck in the nineties for far too long. Look at all these threads where people obsess over amplifiers that haven't been in production for twenty years. C'mon people, it's 2011. Look around - small speakers are the norm today. You don't have to run 6.5" woofers up front, there are small woofers that can do the job better. Look at how speakers have evolved in the last twenty years! Your home speakers are getting smaller every single year - why are your car speakers still hyoooge? Efficiency and size are linked (Hoffman's Law), but power is cheap. That's why home speakers are so tiny now.
Quote:
Originally Posted by XtremeRevolution
This above is something neither you nor the OP has addressed. You will be fine right down to about 500hz, maybe even down to 250 or if you're lucky, even 200, but go down from there to 90hz and you will start having serious problems trying to reproduce linear sound. THIS is why people use WinISD to create massive enclosures for their subs and speakers; because even if you don't need very low frequency extension, you *still* need to be able to play the frequencies your sub cannot, and that will still require you to hit at least 100hz. Many people who build large enclosures to get low frequency extension don't plan on running a sub. Take the speakers I built for my father in law for his birthday based on the Dayton ND105. Very high excursion, and .55 net cubic feet per floor standing speaker that is tuned to 38hz and produces an F3 of 39hz and can play musically down to 32hz. You take that exact same cabinet, shrink it to .2 cubic feet (or smaller if you can accomodate the drivers), make it sealed, pump a lot of power into those drivers, and tell me where the hell my low end extension is going to be.
The problem with WinISD is that it encourages people to treat car audio as if we're working in an anechoic chamber. Cabin gain is very real.
For instance, Sundown Audio has been able to generate something like 140dB with a single eight. 140db!!!!!! Plug those numbers into WinISD and it will tell you that the woofer is good for 110dB.
Cabin gain gives us a TON of headroom. Besides making it trivially easy to make bass below 160hz, the car's cabin also reduces excursion, which is how the SPL guys are able to keep their woofers from exploding. (well, MOST of the time.)
Quote:
Originally Posted by XtremeRevolution
My claim is that if you put your 6.5 comps in pillar pods and reduce your volume to insignificantly low levels in an effort to control excursion, you will have a non-linear response that will drop off sharply the moment you need to reproduce frequencies that require any level of reasonable excursion. At that point, what would have been a 2-way system now becomes a 3-way system because you still need another driver to produce lower frequencies. You otherwise have a gigantic frequency gap between the sub's higher limits and the 6.5 driver's lower limits, and no reasonable amount of equalization will fix it.
Furthermore, you have absolutely no need for a small enclosure "to increase power handling" if you're crossed high enough to where you're not producing any excursion anyway. Why not limit excursion with a higher frequency point instead? Its essentially the exact same thing.
To produce low midbass frequencies, you need either cone area or excursion. You can only fit so large of a speaker in a pillar pod, and you're limiting excursion, so therefore, you will sacrifice low midbass response.
With regard to "Bob's" insanely small enclosure, I would LOVE to see a frequency response chart. Someone with such "revolutionary" designs must clearly have the data to back up his claims. By that regard, so should the OP. This thread is 1.5 years old yet I haven't yet seen a frequency response chart.
Now you're just trolling, you KNOW that spheres have flatter response than rectangular enclosures. You've used The Edge, you know that flat faced enclosures suffer from peaks and dips in the frequency response.
Roundovers and spheres don't just make the speaker SOUND smoother, they MEASURE smoother too.
Build a better mousetrap and the world will beat a path to your door.
Last edited by Patrick Bateman; 04-28-2011 at 01:13 PM..
I have attempted to run a set of 6.5 comps off of my monoblock just for shits and giggles and I didn't like what I heard.
WTF^^^^
99% of all mono blocks are designed for sub duty and designed with a narrow band width for this use. As smart as you claim to be you should know this. Gee wonder why it sounded like crap.
There are many manufactures that were known for class A/B amps know swithcing to full range class D in the last 3-5 years in car audio, if you have not noticed.
06 F250:Zapco-JL-Pioneer, 99 Prelude:JL-DBX-Pioneer, 02 Honda Civic: 80PRS-Hertz-IDQ-JL, 08 Focus: Kenwood-Hertz-IDQ-Zapco, 05 Dodge1500: Kenwood- Pioneer-ID-Zapco---Team JL, Team MSE, Team RAAMmat, Team Zapco---2009 USACi Basic WC, INAC 2nd, 2010 MECA Finals 4th MODEX, 2010/11 OK State Champ MODEX
I have attempted to run a set of 6.5 comps off of my monoblock just for shits and giggles and I didn't like what I heard.
WTF^^^^
99% of all mono blocks are designed for sub duty and designed with a narrow band width for this use. As smart as you claim to be you should know this. Gee wonder why it sounded like crap.
There are many manufactures that were known for class A/B amps know swithcing to full range class D in the last 3-5 years in car audio, if you have not noticed.
From the owners manual of the MRP-M1000 amp:
Frequency Response (200Hz/ -3dB) ....... 20 - 200 Hz
I do know this. The problem is that there aren't very many Class D amps out there for stereo use in cars. Most class D amps are designed for sub duty. I pointed this out to state the obvious. They are not exactly readily available.
We seem to be reaching some consensus here on a few items, but I am not sure why you still seem to think full range Class D is sparse in mobile audio. Off the top of my head, JL, Infinity, Arc, Sony, Kenwood, and Alpine all make full-range class D. These are not small companies with limited distribution.
Quote:
Originally Posted by RNBRAD
...if you have dual climate control, that would be more likely to cause a timing issue ... Sound travels faster through warmer air so lets make sure both zones are the same temperature. lol
Is this better than just using a high-pass crossover? Wouldn't that reduce power and excursion? Or, are you doing this in part for packaging concerns? I feel like I'm missing something here.
BTW, thanks for your contributions. I'm about halfway through reading pretty much everything at your forum, and it's fantastic!
Without a doubt, the main reason that I am a fan of very small sealed enclosures is that it gives you the flexibility to put speakers in weird locations. When I got started in audio in the 90s a 5" woofer was considered "small."
Nowadays you can belt out 110dB with a pair of 3" woofers. That was just impossible back then.
To illustrate how LOUD a small enclosure can get, I've posted some sims in my forum for you guys:
This enclosure is the exact same width as a compact disc, and a pair will do 110dB.
Best of all, small enclosures allow you to create a really strong image in a car. It is very very difficult to create a good image when you're using large woofers with a tweeter that's nowhere close to the woofer.
Build a better mousetrap and the world will beat a path to your door.
Those were the FR charts I wanted to see. You've confirmed my suspicions but impressed me at the same time. I would definitely say you'd need a midbass to play these well, along with a sub. A 4 way system it would appear (if you include the sub as being one). More complexity for better imaging and smoothness. I presume this is all run with active crossovers?
Now *thats* a controversial question!
Here's why -
Most people in car audio have a setup that looks like this:
tweeter covering three and a half octaves, from 2khz to 20khz
midbass covering four and a half octaves from 80hz to 2khz
subwoofer covering two octaves from 20hz to 80hz
With these ultra-small midranges, I'd be looking at something like this:
tweeter covering two octaves from five to 20khz (By using a very high xover point, we move the transition to an octave where it's difficult to detect. (Because we don't hear well at high frequencies.) Reducing the bandwidth of the tweeter also allows us to use very high efficiency options, such as ribbons. A high xover point increases power handling and reduces distortion too.
midrange covering five octave from 160hz to 5khz (this is very important - by covering such a wide range we're hearing most of our imaging cues from one set of drivers. It's almost like a full range system. The idea is to eliminate that godawful xover transition in the midrange.)
subwoofer covering two octaves 40hz to 160hz
ULF subwoofer covering three octaves from 10hz to 80hz (optional)
I would say that this is a very unorthodox set of xover points. Particularly the idea of running your subs up to 160hz.
The reason that the subs are overlapped is because we have a catch-22 here. If we cross over at 160hz, we're going to need to locate our subs carefully so that the imaging doesn't go to hell. But if we want to get to 20hz, we're going to need a big woofer with lots of displacement. So it's a catch-22.
Overlapping the subs solves the "catch-22." A pair of small subs gives you the flexibility to locate the upper subs where they won't ruin your image. And the ultra-low-frequency sub raises our output from 40 to 80hz, and forms a low end that reaches to 10hz.
Note that this setup won't work at home; the ULF depends on cabin gain. At 20hz we're getting about 24dB for free, from cabin gain.
Build a better mousetrap and the world will beat a path to your door.
So tell me right quick why in both automotive and home environments, most stereo amplifiers in the past 30 years have Class A or Class AB and not Class D,
Past three decades, huh? May as well ask me why most stereo amplifiers sold 50 years ago have been tube and not solid state....
Technology moves on. What may not have been viable in 1985 for reasons of chip development, cost, scale of production, etc., is very much viable in 2011.
Quote:
Originally Posted by XtremeRevolution
and why the bulk of the market sells Class D amplifiers as monoblocks for powering subwoofers. You've been implying that there's clearly no reason for that.
You really shouldn't be trying to read into words when you can't properly interpret the plain meaning of the words in front of you to start with!
Read that thread, and note that Harman now has full-range Class D amps in both the Infinity and JBL lines. I don't necessarily expect you to be able to infer why I'm asking you to make that note...
Quote:
Originally Posted by XtremeRevolution
Now, do keep in mind I'm also in the process of building my own Class D amp for stereo use, after having fiddled with a cheap Tripath amp for a while, so I'm not discounting the use of class D in all occasions, but I have attempted to run a set of 6.5 comps off of my monoblock just for shits and giggles and I didn't like what I heard.
So, as others have written, you think class D amps are bad because...you didn't like what you heard when you ran a set of mains speakers off of a subwoofer monoblock?
Wow, just wow.
I bet a Class AB amp with a steep filter at 200Hz would sound like shit driving those speakers, t
Quote:
Originally Posted by XtremeRevolution
Nobody had written that [your understanding of the word directivity determines my intelligence,]
? Sure could have fooled me.
Not "could have." Did. Let's be precise with our language, OK? Though precision would compel one to say that nobody fooled you, except yourself and your puzzling inability to digest the text in front of you in a manner consistent with the standard conventions of the English language.
That said, why are you so willing to throw around terms in a combative way (see, e.g., directivity; see also HIL) when you make it clear in your commentary that you don't understand them?
Quote:
Originally Posted by XtremeRevolution
I don't know what the acronym stands for.
Wow, really? Let's rehash the exchange:
"XtremeRevolution:" and because I support hoffmans law,
"DS-21": Please point out where anyone said anything tending to negate HIL.
"XtremeRevolution:" I don't know what the acronym stands for.
Now, if you had dinged me for that clumsy "tending to negate" instead of a more clear "contrary to" or something like that, I would understand. But I'm sorry, it's not unreasonable to expect someone to figure out how to expand an unfamiliar acronym by just looking at the context.
Why don't you think before you write? It's kind of an important exercise, if one wishes to avoid looking like a fool.
Quote:
Originally Posted by XtremeRevolution
You really think I'm that much of an idiot? It is their flagship receiver.
Again, let's limit the scope of the inquiry to the actual words used, OK?
XR: Oh yeah, and the guys over at denon, yamaha, pioneer, onkyo, and everyone else who sells receivers of any kind are stupid. What are they thinking, class D is so much better. Silly idiots, they should know better.
DS: Let's look at Pioneer's flagship receiver.
XR: See supra.
A reasonable person can certain infer that a company does not think a technology is inferior if they use it on their flagship product, no?
And while I didn't dig deeper at the time, it appears that they offer other receivers with Class D amps as well. And in the past they've offered very cheap ones. I know because years ago I bought one of them.
Quote:
Originally Posted by XtremeRevolution
Considering Class D amplification should cheaper, you should question why it didn't start in the low end.
Well, ignoring your baseless assertion "should be cheaper," the fact of the matter is, it has been in the low end for some time. In fall of 2005, I bought a Panasonic receiver with all of the surround-decoding codecs at the time and a novel ampilfier technology that combines DAC and amp by converting directly from PCM stream to PWM. Tests at the time showed it to have about 80W/ch into 8Ω, I think with 5 of the 7 channels driven though it could have been all 7. (It was >2 channels driven.) It cost me well under $300 new on amazon at the time.
(Why baseless? These things require new parts, often have IP licensing involved, and so on. So over the long term they may end up considerably cheaper, in the short term that does not by any means have to be the case.)
Quote:
Originally Posted by XtremeRevolution
I also specifically stated, commonly available class D amps.
Odd scope shift on your part, because if one can show something is in stock at Crutchfield or Vann's or Amazon it can reasonably be considered "commonly available." This receiver clearly meets that test.
Quote:
Originally Posted by XtremeRevolution
Pioneer's flagship receiver that costs someone both their arms and legs is not a commonly available Class D. How's about we take a $350 class AB receiver and find a Class D receiver to compare it with. After all, the claim was power is very cheap. $2,200 for a receiver is not cheap unless you're made of money, which I'm not.
Let's just say you're obviously not aware of current trends in 120V amplification, just as you are not aware of current trends in 12V amplification. While admittedly they are standalone amps rather than AVR's, Crown, Peavey, Behringer, Crest, and many others offer scads of dirt-cheap power today. For example, a third-party test of Peavey's IPR-1600, which costs just $300, showed it to make 280W/ch into 8Ω and 550W/ch into 4Ω. Peavey IPR-1600 amplifier Test Results :: ABELtronics.
Can anyone reasonably say that $0.55/W into 8Ω, or $0.30/W into 4Ω, isn't "cheap?"
Quote:
Originally Posted by XtremeRevolution
Yes, you can get an assembled amp Class D board from a number of websites (sure being one of them) that will deliver in excess of 100W RMS for dirt cheap, but once again, that's not a commonly available amp.
If you are going to attempt written communication, it helps to be clear with your word choice. "Commonly available" is a term with a defined meaning. "Commonly" means: as a rule; frequently; usually. "Available" means "obtainable or accessible and ready for use or service."
Thus, anything regularly stocked by a major national or regional vender (Amazon, Parts Express, etc.) and made available by them for purchase can be reasonably be labeled "commonly available."
WORDS MEAN THINGS.
Quote:
Originally Posted by XtremeRevolution
I also know that properly designed Class D amps have extremely high fidelity. Tripath proved that it is possible and that it rivals the sound of tube amps, but that wasn't up until a few years ago. These aren't yet mainstream.
Tripath chip amps were in Apple iMacs seven years ago! How much more effing "mainstream" do you want?
And you seem unduly smitten with audiophool idiot-ese, such as "rivals the sound of tube amps" or "sounds as good as something n times the price." Those are phrases that mean nothing.
Quote:
Originally Posted by XtremeRevolution
1. how do you produce midbass if your goal is to limit excursion, and how do you increase output while limiting excursion?
Multiple drivers.
Quote:
Originally Posted by XtremeRevolution
2. once you've explained the above, explain what the frequency response will look like without any equalization.
Who cares? We have sophisticated, pocket-sized EQ at our fingertips. This is 2011, not 1985.
Quote:
Originally Posted by XtremeRevolution
You *REQUIRE* excursion for low frequency extension.
No, you don't. You can get LF extension with EQ.
But if you want LF extension at meaningful SPL, you need volume displacement, not excursion. Volume displacement can be achieved with longer throw, or with greater radiating area, or any combination thereof. One can achieve greater radiating area with big drivers, or multiple small ones. In most cars, I would wager that fitting multiple smaller drivers is stealthier, easier, and (because you also get the benefit of "room mode" randomization) better-sounding.
That doesn't necessarily hold for cars like my daily driver, which is a small convertible. In such a car, one needs as many big drivers as will fit.
Quote:
Originally Posted by XtremeRevolution
The above quoted post claims to defy Hoffman's law, that you can simply put the drivers in an extremely small enclosure and pump more power into them to get the same output.
Actually, all you're showing here is that you don't understand HIL. To paraphrase: HIL is the following: you can only have two of the following three things: small cabinet volume, LF extension, and efficiency.
A tradeoff of small volume + LF extension + inefficiency mitigated by application of massive power falls entirely within HIL.
Quote:
Originally Posted by XtremeRevolution
If we could all get all the bass extension we ever could out of a sub box that barely fits our subs,
We can. Some people do. Heat management just becomes more important at that point.
Quote:
Originally Posted by XtremeRevolution
you *still* need to be able to play the frequencies your sub cannot, and that will still require you to hit at least 100hz.
Then get a sub that can play higher. There's no reason to limit subwoofer highpass frequencies so. Localization in a car is mostly caused by rattles, and the only way not to excite them is to tame them. That's why even cars with subs at your feet can exhibit "bass in the back."
It's trivial today to find a subwoofer driver with an 18" cone, ~20mm xmax, AND inductance low enough to play up to 700-800Hz. (Aura makes a bunch of 'em.) At home, I run 150Hz (admittedly, with mains also run full-range, and the subwoofer drivers are all clean to around 1kHz) and there's no localization issues. Maybe there would be with a corner sub, but not with a well-implemented multisub system and, again, the mains also playing the bass. Overlapping is your friend.
Quote:
Originally Posted by XtremeRevolution
I shudder at the thought of Sony and Kenwood amps, but especially Sony. I run Kenwood amps in my car and that's only because I didn't know any better when I bought them and I haven't gotten around to replacing them. I run two kac-7203 class AB two channel amps.
There was a big discussion on this on techtalk.PE and a general consensus was that power on reserve in a larger amplifier than is needed is often a good thing as it has the capability of playing with a much better dynamic range and avoids the risk of clipping and/or distortion at higher volumes as a result of dynamic peaks.
Hmm, I wonder who wrote that "general consensus." IIRC, the phrasing went something along the lines of,
"The reason bigger amps often sound better is that they have more headroom to avoid clipping on peaks. There's no point delving into minutiae when that simple and obvious statement explains so much of the observed variance in controlled conditions. (The rest is generally noise floor.)"
Since you were willing to accept my take on why higher power is generally better, you should also read my thoughts on that vacuous, pointless article and take them to heart.
Since you were willing to accept my take on why higher power is generally better, you should also read my thoughts on that vacuous, pointless article and take them to heart.
Not to mention, that article was written in 2005. A lot has changed since then regarding the technology associated with full range class d amplifiers. I'd be willing to bet that Xtreme couldn't pass your amplifier challenge, or mine for that matter.
Also, why is there so much bickering about amplifier topology in an "improve your soundstage" thread? Amplifier topology has NOTHING to do with the soundstage.
2012 Subaru WRX - JL Audio C5-650s run active off a Lunar L450; Digital Designs 1508 powered by a Lunar L1500; Pioneer DEH-80PRS as the source unit.
Re: Improve Your Soundstage for $2
. 
Linear Mode
