Midrange mounting location: 2 Options Only

[NoMids]

Hi Guys,

I've acquired some equipment and found a reputable shop (I don't know if it's appropriate to list the name) to do the installation. The time has come to make some decisions about midrange and tweeter placement. I'd like your opinions regarding potential imaging problems.

My equipment:

Car: Pontiac G8 (Leased, so we're not cutting any holes)

HU: Factory (unit has integrated HVAC controls so I didn't want to change it)

Processor: Bitone.1

Subs: jl 12W3V3-4's in a sealed box (currently installed)
Sub Amp: JL 500/1v2 (currently installed)

Front Stage: Hertz HSK 163 Component Set (purchased from a forum member)
HV 165L Woofer (Midbass) Going in the factory door locations
HL 70 Midrange
HL 25 Tweeter

Front Stage Amp: Zed Leviathan (It shipped today!)

Originally, I was going to have a set of kicks fabricated from fiberglass. In the kicks we were going to mount the mids and tweeters. Then I found out the price of the kicks ($650 - $325 a piece) and that totally blew up my budget. The shop's owner suggested that, instead of the kicks, I consider putting the tweeters in the factory dash locations (on angled mounts under the plastic factory covers) and one mid in another factory location at the center of the dash. Could this work well? I really have no idea. I've never heard a car with one mid in the dash before.

I'd like some input before we take the car apart. The Leviathan won't be here until October 6th or 7th so I have some time. If you feel that the different speakers in the dash would help, please make suggestions.

This is my first real attempt to do something on the higher end with any car that I've had. I'm really hoping for better than average SQ results. I've read so much about how some cars sound like the front stage is "on the hood." I'd love to experience some of that satisfaction with my car.

Please ask questions, make comments, even flame the noob if you have to... I'm in over my head, knowledge and experience wise, so I'm hoping for some structured guidance.

Thank you,

Tom

[bikinpunk]

Originally Posted by NoMids

This is my first real attempt to do something on the higher end with any car that I've had. I'm really hoping for better than average SQ results. I've read so much about how some cars sound like the front stage is "on the hood." I'd love to experience some of that satisfaction with my car.

Honestly, if you think you can afford it at some point, I’d hold off until I had the money to put them in the kicks. But, then again, I know nothing about your drivers so I don’t know what the best real environment for them would be.

Originally Posted by NoMids

The shop's owner suggested that, instead of the kicks, I consider putting the tweeters in the factory dash locations (on angled mounts under the plastic factory covers) and one mid in another factory location at the center of the dash. Could this work well? I really have no idea. I've never heard a car with one mid in the dash before.

Sounds like he’s telling you that the one mid will be a center channel. Can’t do that with the bitone because AFAIK you can’t do L+R summing to get a true mono signal. This leaves you with either sending a left signal or a right signal to the midrange in the center which is not going to work.


What about taking his advice for the tweeters right now until you have the kicks made?
Go ahead and wire the car up for the mids, get everything set up for them. Then when you have them built, you’ll be ready to rock.

My $.02.

[jimp]

there's a post on this site about using pvc pipe as speaker test modules/holders, believe in the tutorial section, guy use the appropriate size pvc pipe to make a "holder" so to speak so he could test different locations 2w/o having to mount the speaker anyway, worth trying maybe.

[m3gunner]

Path lengths are much more critical in the midrange, so I think I'm with bikinpunk on this one. Kick panels are expensive because they are labor intensive *and* because they work so damn well to equalize path lengths to give you that "on the hood" experience. You certainly won't get that with a midrange on the dash unless it's properly set up (and it appears the Bit One might not be able to do that...).

If it were me, I'd take the tweeters on the dash for now with the midbass drivers in the doors and save up for the kick panels. You might like it enough with the TA and EQ to bypass the kick panels. Up to now, I've been good with a two way up front (even though my ultimate system will have a 3 way...) and you're looking for "better than average SQ"... you have good equipment and, hopefully, a good installer and this might end up being a good solution for you...

Think in terms of amortization... $650 over 5 years works out to about $.35 per day. For the kind of imaging you can get from well placed and integrated kick panels, that's chump change.

[Patrick Bateman]

Based on the email you sent me, I posted some basics on how we perceive sound locations here:

http://www.diymobileaudio.com/forum/...stage-2-a.html

If someone told you they were able to get the soundstage "on the hood", I would ask them to demo their car. The soundstage in my car is the best I've ever heard in a vehicle, but the only way to get depth that exceeds the dash is to put the speakers further away than the dash. Or use processing. If you control diffraction and reflection on the midranges, it IS possible to get stage width which exceeds the dimensions of the car. Occasionally I hear elements of the soundstage in my car which appear to be coming from the left or right of the vehicle itself.

I used ambiophonics processing briefly, and it did indeed improve the depth, but the downsides were too serious to live with.

Anyways, back to the original question: Where to put the speakers?

The width and the depth of the soundstage is largely determined by where the sounds of the midrange are emanating from. Midrange is what we're most sensitive to, so the engineering and location of your midrange speaker(s) is critical.

Putting the midrange in the center would give you good depth and intelligibility, but the system would be mono. Even with three midranges up front the soundstage would be narrower than with two midranges located as far and as wide as you can place them.

Anyways, long story short, here is what I would do:



First, the tweeter is a no-brainer. In this pic of the G8 interior, the stock tweeter locations are pretty darn good. You're going to get a peak and a dip in the tweeter due to the windshield. If you decide to use that location, measure the distance from the windshield to the tweeter location, and I can tell you where the peak and the dip will occur, and then you can figure out if it's going to be audible enough to get annoying. If it's a gap of one inch, the dip will occur at 3375hz and the peak will occur at 6750hz. Higher is better (ie less audible.)

The crossover on the Hertz tweeter is 4500hz, so the dip will occur below the tweeter's passband if the gap between windshield and tweeter is less than an inch.

Second, the midrange is the most critical. Far and wide is the plan here, as the midrange location will define your soundstage. Personally, I would try to get it up on the dash somehow. I looked up the specs on your midrange, and it will basically work in any sealed enclosure that you put it in. Even an enclosure with virtually no air space is sufficient. According to my calculator, even an enclosure that measures 3" x 3" x 3" is big enough. (Of course the mid wouldn't even fit.) I've never messed around with Hertz components, but they look very well designed; in particular the shallow depth of the midrange opens up installation possibilities which are impossible with a two-way. Normally I prefer two-ways over three-ways, but I gotta admit that a midrange with a depth of less than two inches makes creating a soundstage quite easy. I took the specs from here:

http://www.hertzaudiovideo.com/Doc/pdf_hl70.pdf

So my first choice for the midrange location is in a teeny tiny enclosure on the dash, with a roundover, and located at a distance from the window and the windshield which is calculated to avoid reflections. THe math for the calculations is the same as above.

My second choice for the midranges is as far under the dash as you can possibly get it. Because the midrange crossover is at 4500hz, you'll want "line of sight" to the driver and passenger. Again, the width and the depth of the midranges will define the soundstage.

My last choice for the midrange location is in the doors. Normally I don't recommend putting speakers in the doors, but in your car, the door locations are quite high. This will ruin the depth of the soundstage. On the plus side, it will raise the height, and it's an easy install. If you put the midranges in the door, be sure to seal them. Sealing the midranges will basically quadruple their power handling and lower distortion. Your midranges don't need much airspace, so running them infinite baffle won't get you much bass, and it will kill your power handling.

I would put the midbasses wherever they will fit. Remember, distance is key at low frequencies. The problem with putting midbasses in the door is that it kills the depth of soundstage which you worked so hard to engineer. In my car the midbasses are located on the rear deck, which is nearly five feet from my head. If I were to put my midbasses in the door it would bring them way too close, since the door locations are only three feet away.

Below 1500hz, pathlength rules.

[mxl16]

Originally Posted by bikinpunk

Sounds like he’s telling you that the one mid will be a center channel. Can’t do that with the bitone because AFAIK you can’t do L+R summing to get a true mono signal. This leaves you with either sending a left signal or a right signal to the midrange in the center which is not going to work.

What makes you think you can't do L+R summing with the B1? Just curious. In the initial setup it definitely has a center channel option. It would seem ridiculous to have a "center" channel option and not properly derive it. I am curious because I want to use my B1 and put a center in my truck. Guess I can call elletromedia.

[bikinpunk]

I had to pull up the software to look, but you are right. It does have center.

I was going off memory, trying to recall ever seeing this option, and also the fact that someone on this board had once asked about if you can make it sum L+R for center.

So, you were right. I was wrong. Good deal.

[tosca]

Originally Posted by Patrick Bateman

In my car the midbasses are located on the rear deck, which is nearly five feet from my head. If I were to put my midbasses in the door it would bring them way too close, since the door locations are only three feet away.

I would love to hear how you make this work, especially with a mid like the hl70.

If you were to put something on your back seat, and it vibrated just enough for you to hear, would your midbass still be upfront or would it all shift to the back?

[NoMids]

Hi Everyone,

Please forgive my delay in responding to "your" collective input. I've been battling the flu

Originally Posted by Patrick Bateman

First, the tweeter is a no-brainer. In this pic of the G8 interior, the stock tweeter locations are pretty darn good. You're going to get a peak and a dip in the tweeter due to the windshield. If you decide to use that location, measure the distance from the windshield to the tweeter location, and I can tell you where the peak and the dip will occur, and then you can figure out if it's going to be audible enough to get annoying. If it's a gap of one inch, the dip will occur at 3375hz and the peak will occur at 6750hz. Higher is better (ie less audible.)

The crossover on the Hertz tweeter is 4500hz, so the dip will occur below the tweeter's passband if the gap between windshield and tweeter is less than an inch.

First, please remember that I'm going to be using the bitone for processing, so the crossover points are wherever we decide they should be.

Second, pulling out a tape measure, the center of the tweeter grills are at the following locations:

Distance from windshield edge (at hood) to center = 1.75"

Distance from a-pillar to center = 1.75"

Distance from windshield down to center of the grill = 1.50"

Tweeter Questions:
1. Assuming the tweeters are centered under the grills, what would be the ideal crossover frequency?

2. Based on this crossover frequency, should I use that number to calculate a roundover for the tweeter's baffle?

3. It appears that the tweeters are sealed. Does this mean that I should not concern myself with putting them in an enclosure?

4. Should the center of the grill be abandoned as the default location for the tweeters and every attempt be made to be 1" off the windshield and 1" off the a-pillar?

5. I do not want to cut the factory tweeter grills, nor do I want to have new grills made. Would there be a significant negative to mounting these under the factory grills?

6. Should the tweeters be mounted at an angle, under the grills? If so, should they be aimed at the dome light or would mirroring the windshield angle be alright?

Originally Posted by Patrick Bateman

Second, the midrange is the most critical. Far and wide is the plan here, as the midrange location will define your soundstage. Personally, I would try to get it up on the dash somehow. I looked up the specs on your midrange, and it will basically work in any sealed enclosure that you put it in. Even an enclosure with virtually no air space is sufficient. According to my calculator, even an enclosure that measures 3" x 3" x 3" is big enough. (Of course the mid wouldn't even fit.) I've never messed around with Hertz components, but they look very well designed; in particular the shallow depth of the midrange opens up installation possibilities which are impossible with a two-way. Normally I prefer two-ways over three-ways, but I gotta admit that a midrange with a depth of less than two inches makes creating a soundstage quite easy. I took the specs from here:

http://www.hertzaudiovideo.com/Doc/pdf_hl70.pdf

So my first choice for the midrange location is in a teeny tiny enclosure on the dash, with a roundover, and located at a distance from the window and the windshield which is calculated to avoid reflections. The math for the calculations is the same as above.

The location of the grill that covers the midrange:

Distance from windshield edge (at hood) to center = 6.50"

Distance from windshield down to center of the grill = 4.50"

There isn't much depth available close to the windshield. Considering the car is leased and cutting the dash would be frowned upon by the leasing company (if anyone ever looked under the grill), it would be preferred that the midrange speaker was centered in the grill. However, if the consensus is that the negative impact of moving the mid to the center of the grill location will ruin the imaging then, I'll roll the dice, and cut the dash.

Midrange Questions:
1. Assuming the midrange is centered under the grills, what would be the recommended crossover frequencies? I'm assuming this speaker will need a bandpass setting.

2A. If centering the mid is determined to be too great a negative to overcome, then please recommend a distance from the edge of the windshield (hood) and distance down from the windshield.

2B. If the mid is placed other than centered in the grill a custom baffle / enclosure and grill will be fabricated. Should the baffle angle the mid towards the passengers? Should it be aimed at the dome light or will mirroring the angle of the windshield be sufficient?

3. Assuming that I mount the midrange in a small sealed enclosure, which frequency should I shoot for when calculating radius for the front of the baffle?

4. Because there will only be one midrange speaker, should I consider using a 4" mid instead of the 3" speaker that I have with the component set?

Originally Posted by Patrick Bateman

I would put the midbasses wherever they will fit. Remember, distance is key at low frequencies. The problem with putting midbasses in the door is that it kills the depth of soundstage which you worked so hard to engineer. In my car the midbasses are located on the rear deck, which is nearly five feet from my head. If I were to put my midbasses in the door it would bring them way too close, since the door locations are only three feet away.

Below 1500hz, pathlength rules.

I have the option of putting my midbass drivers in the door or in the rear deck.

Door Location Questions:
1. If I put the Hertz HV 165 L's in the doors should they be in sealed enclosures or will IB be satisfactory?

2. What are the suggested crossover frequencies? Again, I'm assuming that these speakers should be bandpassed.

3. What is the recommended frequency that I should shoot for when calculating the roundover for the baffle?

Thoughts on using the deck for midbass:

From the factory, my car has 2 - 8" speakers running IB in the deck

The deck speakers are about 48" from my head to the center of the grill on the driver's side.

The center of the grill is 6.50" from the c-pillar

The center of the grill is 5.50" down from the back window

The center of the grill is 14" from the edge of the back window (trunk side)

Originally, I had purchased a pair of jl 8IB4's with the intent of putting them in the deck IB as additional midbass to the Hertz 165 L's in the doors. I had taken them out of the equation because of feedback I'd received and what I'd read about having 2 different sets of speakers handling the same set of frequencies. Can anyone offer some additional input regarding the inclusion of the JL 8IB4's?

Since the speakers are 8 ohms, I'd have to wire them in parrallel to get any real output out of them on the last remaining channel of the Leviathan amp (2-channels for the tweets, 2-channels for the door midbass, 1- channel for the center mid, and one channel left over for the 8's?). Would running these mono add to the fill or just hurt the sound stage?

Would anyone consider running these in the deck instead of the Hertz 165 L's in the doors for midbass?

And, finally, should I be concerned that the sound pressure of the subs firing in the trunk will distort the response of the 8's in the deck? If so, is it best to abandon the idea of deck midbass? I've read that the JL 8IB4's would need a large enclosure to sound right and, unless highly recommended, the added expense and loss of space in the trunk are hard for me to justify.

Please allow me your thoughts.

Thanks guys,

Tom

[jel847]

midbass on the rear deck is very interesting and something im considering in my GTO. im curios what kind of processing your usig other than crossovers?

[SkodaTeam]

If you are "hoping for better than average SQ results" i can recomend to change at least the midranges HL70! You will loose a lot details wiht them! My opinion.

[Patrick Bateman]

I started making a reply to this thread TWICE and didn't finish the post...

So if I'm repeating myself here, my apologies.

I would use the stock locations with the Hertz tweeters, as long as they fit. The owner of the car emailed me, and said that there's enough room. It's import that the tweeters are flush with the dash, othewise the response will get screwed up. The easiest way to flush-mounth the tweeters is to fill the gap around the tweeter with modeling clay. Just press it into the gap until it's perfectly flush.

Of course, be careful to keep the clay away from the tweeter diaphragm.

As for the midrange, the stock location is a bit iffy. As mentioned earlier, I'd put the stock mid as far and as wide as I can find

The stock crossover that's included with the tweeter should be sufficient, I don't see any advantage to using an electronic xover. IIRC, it high passes the tweeter at 4500hz. There will be a peak in the response at 3857hz due to the reflection off the windshield, but that peak is below the stock xover frequency, and will be attenuated by the filter.

[Hernan]

Originally Posted by Patrick Bateman

In my car the midbasses are located on the rear deck, which is nearly five feet from my head. If I were to put my midbasses in the door it would bring them way too close, since the door locations are only three feet away.

Below 1500hz, pathlength rules.

I like very much your contribution to the site

Midbasses at the rear deck? Is not a bad place if your are looking for good pathlenghs but... where do you lowpass them?
A sub playing above 120hz is very easy to localize at the trunk... I don't understand how midbass coming from the back of the car could blend with the rest of the frontstage.

[NoMids]

UPDATE:

The install is complete and I'm pleased with the results... so far

Impressions:

The bitone.1 is really a nice product. I haven't had any noise issues. I've had a few afternoons spent adjusting the set-up and am impressed by the tuning flexibility. We haven't RTA'd the car because I'm getting some run time on the speakers to break them in. All speakers were bought used, but with minimal playing time on them.

The Leviathan does have the turn on / off pop. It's not apparent in my car anymore because the bitone turns on the amps, however when we had the Leviathan on a seperate remote wire it popped very loud. Zed has said that it can be returned at no charge (they'll pay the shipping both ways) to be "fixed", but since I've just finally got everything in the car I don't want to give it up yet. The amp is quiet and seems to have tons of output. I've never had 150 watts per channel before so I can't comment on it being over or understated in it's rating. Considering I had paid almost as much for my JL G6600, from a dealer, I think the Leviathan is a bargain.

Layout:

I used the HL25 in the stock tweeter locations crossed over at 3250 with 18dB slope. I did not fill the opening with modeling clay. We made a bracket and mounted the tweeter. Can someone please explain why filling the remainder of the opening would be an improvement? Would stepping up to a HL28 or set of HAT L1 pro's help me get a bit more "midrange" or would my mounting location negate the ability to run the tweets lower with good sq?

I changed the midrange in the dash to a Morel CDM88 running from 700 - 3500 at a 12dB slope. I crossed the tweeters over lower to get some overlap with this speaker. The stage is high and upfront, but I think I'm going to have to remount the Morel. I didn't enclose it. It's mounted to a baffle that was angled to mirror the slope of the windshield. It sounds OK at these frequencies, but not any lower. I'm not going to say it sound like a giant tweeter, but it sort of sounds like a giant tweeter when I'm listening to Led Zepplin I'm going to have to do some on going work here to improve this. Can someone recommend an enclosure size for this speaker. I'd like to run it as low as possible.

I have the HV 165 L's in my doors. They are mounted to large (10" x 10") 3/4" thick MDF baffles that are screwed to the door's sheet metal. The entire door is deadened, both inside and out. I have these crossed over from 60 - 700 with a 12dB slope. I've had them up to 1750 and they sound great. I don't want to run them up any higher in my car because it ruins the sound stage. Also, they don't hit as hard as I would have hoped. I'm running the Leviathan with almost full gain on these and the bass from them is marginal. I understand that they are only 6.5" speakers, but my stock speakers had more low end. Could it be that we missed something when we sealed the doors? Please chime in.

I have the 12w3v3's in a sealed box. IIRC, the box has an interior volume of about 1.2 cubic ft per chamber. These are crossed over at 60hz on a 12dB slope. The box is loudest in the upper frequency range, but really falls off in the lower frequency range. You hardly feel them. Is it that I have these under powered or is this all I can expect out of 12w3's in a sealed box?

Thanks for all your help so far. I've learned a lot, but have a ways to go.

[TREETOP]

Originally Posted by NoMids

I changed the midrange in the dash to a Morel CDM88 running from 700 - 3500 at a 12dB slope. I crossed the tweeters over lower to get some overlap with this speaker. The stage is high and upfront, but I think I'm going to have to remount the Morel. I didn't enclose it. It's mounted to a baffle that was angled to mirror the slope of the windshield. It sounds OK at these frequencies, but not any lower. I'm not going to say it sound like a giant tweeter, but it sort of sounds like a giant tweeter when I'm listening to Led Zepplin I'm going to have to do some on going work here to improve this. Can someone recommend an enclosure size for this speaker. I'd like to run it as low as possible.

My personal thoughts about running a single midrange aside, it's good to see you got your equipment installed and you seem reasonably happy.

The Morel CDM88 is designed to work without an enclosure, that's why it has no rear chamber. Adding an enclosure to it is likely to do nothing.
You can try crossing its highpass lower as-is, you'll likely find that it sounds better at lower volumes but you'll be limited as far as distortion-free volume goes. Crossing it lower than 500hz or so will likely sound like butt at high volume.

Originally Posted by NoMids

I have the HV 165 L's in my doors. They are mounted to large (10" x 10") 3/4" thick MDF baffles that are screwed to the door's sheet metal. The entire door is deadened, both inside and out. I have these crossed over from 60 - 700 with a 12dB slope. I've had them up to 1750 and they sound great. I don't want to run them up any higher in my car because it ruins the sound stage. Also, they don't hit as hard as I would have hoped. I'm running the Leviathan with almost full gain on these and the bass from them is marginal. I understand that they are only 6.5" speakers, but my stock speakers had more low end. Could it be that we missed something when we sealed the doors? Please chime in.

Phase shift could be the culprit, they could be electrically in phase but acoustically out of phase by the time their output reaches your ears. Play with polarity, switch the + and - of one midbass driver and see if that strengthens their attack.

[NoMids]

Thanks, TREETOP.

You're dead on with running the CDM88 any lower. We had it at 550 and it didn't sound good at higher volumes. It might be the baffle. It's such a pain in the a** working so close to the windshield. It's mounted pretty well, but it did vibrate when crossed over lower. The cross over points were chosen because that's where I get minimal movement. If I shored it up do you think it would run lower?

Someone mentioned a dome mid would be best in my application. I searched and read a few threads that agreed so I bought the CDM88's. Do you think that Patrick's original suggestion, of running the HL70 in a sealed enclosure, would produce better results?

The bitone allows me to phase shift a channel. I've done this for the HL 165's and they do sound better. Anyone running these? How low do you have them crossed over? Suggestions for mounting?

[TREETOP]

Given your equipment list, if it were me and my vehicle, I'd put the CDM88s in the kicks.
I feel pretty strongly against only using a single midrange driver in the center of the dash, I think you'd be WAY better off using both of them and having an actual stereo image.
Your original price quote for kickpanels was with the Hertz midrange speakers, which would definitely require a bit of work. If you were to put the CDM88s in the kicks, the labor would be leaps and bounds easier. The reason for this is twofold- There would be no concern about airspace or sealing/venting the kickpanel enclosure since the CDM88 is self-contained, and there would be a LOT less emphasis needed towards getting the drivers on-axis since they're domes and off-axis response closely resembles on-axis response up to and beyond where your tweeters are taking over anyway.

Your mids would be closer to your midbass drivers this way also, which would be a plus in my opinion.

[bobduch]

The problem with a dome mid is they can't go very low. But they would work fine with the 700hz xover you are using. And domes are sealed. Meaning you don't need an enclosure. So you would not need expensive kicks made. You could simply set them up in the kicks with minimal brackets. You could mount them in the factory plastic panels on your kicks and just buy an extra set of panels (junkyard used maybe) pretty cheap and your good to go.

[Hernan]

I have experimented with center channels and at the end I don't like them for plain stereo.
You get a solid center imagte, good vocals. You loose stage width and ambience.

The W3 is a very good sub. 12dB slope is too shallow for a car subwoofer at the trunk. Try 24dB. If you have too much bass and no subass, use some eq to lower around 50hz and re tune the gain.

After that, you have to found where to HP the midbasses.
First a polarity check. Out of polarity sounds strange and thin.
Your speaker, at your install, have a natural rolloff. You must select the HP that complements this curve. The book recipe 80hz/18dB does not sound well but it protects well the speakers.

Experiment with different slopes. In my car, I use 100hz/6dB HP to get a flat response down to 50.

If you own two morel domes, the kicks is a good home for them. I prefer the midranges next to the woofer, just where the kickpanels starts.

[bertholomey]

I am very interested to find out if you mount the 88's somewhere in the kick panel location. I am having the same thoughts - either 54's or 88's in the kicks or bottom forward portion of the door.

A couple respected members have domes mounted in the kicks firing off axis with excellent results. I would like to do this versus build pods for cones on the dash / a pillar.

I'm glad you like the Bit One, and I hope everything works out with the mid bass driver output.