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Discussion Starter #542
Alum sounds just fine.
It's just how Copper sounds after 10min of rippin on it hard.
Copper seems to have better detail at high levels for long periods.
It's more conducive, so will have less resistance when hot.

(I guess I could have just said power compression)

At mid volumes I couldn't tell you what kind of coil any speaker has.
At levels I listen to , it's pretty easy to tell once I learn the driver and how it performs and after making sweet sweet love to it . BLAWU! :D
Oh yeah now I remember, you explained me that already once but I forgot.



Why? Did I sound sniffy?
Yeah maybe after re-reading... well sorry that was involontary! (And maybe it's worst :D)
To add a bit on what I know and what I don’t (or what I think I know :p).
Of course I have a lot more to learn, but also need to move on and keep learning.

Enclosure volume:
I target something like 0.3 cu ft, based on few measurements in kicks I think it's reachable, if I don't mess up the enclosure.
Maybe more if I can extend it higher under the dash or beside the footwell.
This volume is acceptable on all modeling I've done for the 10 sealed, not the best for sure, but ok to cross around 70/80Hz with headroom.
Bigger would be better of course, but the gain is not super obvious visually in the software. Maybe this gain is more subjective, and is hearable IDK (following point).

Qtc/ringing:
After my tests on the door boxes, different AP and box volume, etc, I finally didn't hear many advantages over the smaller volume.
It looked better on FR/impedance measurements while didn't sound much cleaner, with or without EQ/Dirac. And too big was even worst, but it was only a 8.
It might have been something totally unrelated like box shape, box resonances etc IDK.
But sure I’m now limited, it sounds better crossed at 100/120Hz than at 80Hz.
I'm ok with the trade off on low extension, 80Hz is ok for moderate volume but louder it sounds strange, less sharp (don't know if it's ringing related).

SPL needed:
Here I'm in the blur, I don't know a lot but sure I enjoy the louder/cleaner levels of the horns and actual 8.
Usually listen to moderate levels like maybe around 100db, but sometime I want to go over but for a short time (I don't keep my eyes on the meter but I've seen numbers like 110/115 C-weighted if I remember).
And I have no clear idea how this number really represents each driver effort, when they all play together I mean. So I just target the best I can fit.
Also, Dirac needs headroom with sometime big boosts down low, sounded good to oversize the system a bit.
(BTW I never took the time to measure the system post Dirac)

All this combined I don't imagine a regular driver keeping up, but maybe I’m wrong.
So yeah please tell me if I missed something or what I miss-interpreted!
 

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You have got to start trying Dirac with a massive cut and don't let it boost more than 3db.

Dood .....it sounds better.

I don't think I'll ever tune that way again.
After some playing with it, it works just like a graphic (of sort)

I fully admit I was doing it wrong. (And trying to learn how to master it)
Much much less distortion especially on horns and midbass.
 

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Why? Did I sound sniffy?
Yeah maybe after re-reading... well sorry that was involontary! (And maybe it's worst :D)

I didn't read it as sniffy fwiw. ;)

I see what you are saying.

There are always trade-offs. You can do a pro-audio driver but they could have drawbacks too, like less excursion, higher FS and higher distortion at the lower end of the FR spectrum that you want them to be able to play at.
Sensitivity to me is not a huge concern because we're not lacking in power to drive the speakers. Also, if you have a target SPL you want to be able to reach, you'll probably find that most of the non-pro audio speakers mentioned will get you there no problem. Power compression for most quality drivers is not going to be a big issue with reaching that SPL goal.

I liked the idea of the pro audio midbasses and had modeled and considered them a couple years ago when I was looking hard at using the 10NW64.
The problem is that you can't have the best of all worlds. You won't get excellent sensitivity, low FS and be able to use a tiny airspace with almost anything out there. My thinking was why did I want to then do a proaudio woofer that could get very loud, but would be playing well into and below it's FS where the distortion is highest? The tradeoff of louder/sensitivity for quality and extension didn't seem to make sense to me when I could simply add more power to the less sensitive driver.


You may want to experiment and check something...
Try measuring your driver's parameters with a woofer tester so you can get an accurate QTS and then put the driver in the enclosure and measure it again. Then what happens if the bottom/back of the enclosure is opened up to vent into whatever holes are existing in the kick area? How is qts affected? You may need less venting area then you think, but it's worth at least experimenting to see.
 

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Discussion Starter #545
I didn't read it as sniffy fwiw. ;)

I see what you are saying.

There are always trade-offs. You can do a pro-audio driver but they could have drawbacks too, like less excursion, higher FS and higher distortion at the lower end of the FR spectrum that you want them to be able to play at.
Sensitivity to me is not a huge concern because we're not lacking in power to drive the speakers. Also, if you have a target SPL you want to be able to reach, you'll probably find that most of the non-pro audio speakers mentioned will get you there no problem. Power compression for most quality drivers is not going to be a big issue with reaching that SPL goal.

I liked the idea of the pro audio midbasses and had modeled and considered them a couple years ago when I was looking hard at using the 10NW64.
The problem is that you can't have the best of all worlds. You won't get excellent sensitivity, low FS and be able to use a tiny airspace with almost anything out there. My thinking was why did I want to then do a proaudio woofer that could get very loud, but would be playing well into and below it's FS where the distortion is highest? The tradeoff of louder/sensitivity for quality and extension didn't seem to make sense to me when I could simply add more power to the less sensitive driver.


You may want to experiment and check something...
Try measuring your driver's parameters with a woofer tester so you can get an accurate QTS and then put the driver in the enclosure and measure it again. Then what happens if the bottom/back of the enclosure is opened up to vent into whatever holes are existing in the kick area? How is qts affected? You may need less venting area then you think, but it's worth at least experimenting to see.

Ok nice captainobvious thank you, I re-considered few things…

#1 SPL levels
#2 PA or home drivers
#3 vented, ported or sealed
#4 floor considerations


All the following stuff is probably basic for you guys, but it helps me to summarize, typing it helps to clear up and memorize things.


1, So first I think I really need to define the SPL level needed.

What I know:
I mostly cut, and a lot, but can also boost very little here and there on C-dsp.
And Dirac adds on this his own boosts in the 80Hz area.
How much I don't remember exactly but probably between 3-6db based on Dirac graphs before/after predicted.
It is acceptable for moderate volume, but not so clean if much louder.

In my box with only one of the filter I commonly use, real driver T/S simulated in winisd, the 8mbx gives 117db at AES power in midrange.
But since it's sealed, it's down to 111db at 100Hz, and 108db at 80Hz.
It's not a surprise it was the goal, high sensitivity to compensate the low end loss.
So I cut a lot over 150Hz (around 10db in some places) and boost a little below.
But here it's already over excursion limits. And this doesn't count for the EQ from Cdsp/Dirac.
So at the end it's probably much over.

Not knowing how much final EQ is really used, I simulated a 6db boost at 80Hz, Q=1:
At 20% power it's 111db/300Hz, 109db/100HZ, 107db/80hz, and right on excursion limit at 80Hz
Same without any filter, 107db at 80Hz is the limit.
So it seems to say that I need a driver that can deliver either more than 107db at 80Hz,
or just 107db while still being within its excursion limits.
Good start!

So in real world:
Since I can't measure real excursion I can still try to verify the theory with REW.
With few sweeps full range & high passed at multiple levels I could study where it starts to fail.
And this will include cabin gain, that in my car starts around 75hz.
When max level is reached, when power compression starts to impact, when distortion becomes an issue etc
I kind of do that when I tune but never really tried to reach the limits, I'm mostly tune for a moderate target level.
Checking distortion will be harder without real music.
I mean my REW plots are not super relevant I always had inconsistent results,
like if it was too sensible too external noise, or internal resonances maybe (often the louder has less distortion).
And all this will be "raw" compared to final listening context.
Cdsp+ Dirac with their EQ will potentially change a lot the result.
But at least I'll have the limit to compare to.

Does it make sense?


2, PA or home drivers:

After all this I think I'll have a better idea of what I need.
Then I could simulate a bunch of drivers again, PA or hifi and see what I could use.
That was kind of the idea behind using a PA10". Something that can accept all EQ and power, while still under excursion limit.
But the good thing with a home driver, I won't have to boost it as much on low end, as soon as it gets the needed enclosure volume.



3, Then ported/vented outside/sealed

Too early to answer that.
Other than listing the inconvenient of ported midbass that I see (steep LP, potential port noise, complexity)
Advantage being always lower excursion, even with smaller box size.
And something else, the FR response difference is less and less obvious when the driver starts to get to its power limits.
Did you notice this on measurements from V.Dickason/Voicecoil mag for ex?
Low level ported and sealed are really different, but max level they always look very close!

Venting out, I tried some experience with the door boxes.
At the beginning they had a hole right behind the driver, firing into the door, with fiberglass etc
I used the dayton thing to measure impedance/Qts etc while changing filling of the box/thickness and layers of the vents etc.
I could get a much cleaner impedance curve for sure.
Final Q changed a lot also, and I was trying to reach a lower one.
But once in the car, once EQed etc, they didn't sound much different.
And I didn't care much about the Q anymore.
In fact I always preferred the sealed version, that's why I have sealed my actual boxes.
But they're only 8" with a good volume for them.
Maybe the story will be different with a 10"

Another question on venting/AP, is it considered closer to IB or to ported?
Because on my measurements, it always looked more like a bad "ported".
But maybe it was the box shape (long and thin)


4, Floor considerations

One think I could consider, is venting in the floor. I don't mind cutting here it's easy to refill and not structural.
But I must say I wonder how does it sound from outside.
Is it disturbing for other people?

After some more readings on kick/footwell sub/midbass, it appears the floor can be a big problem, resonance/peaks etc.
And my floor is definitely not one of the best, long and flimsy.
So what's best here? decoupling or rigidifying?
I could add a false floor in wood, or even brace it with some metal panel, glued on.
Or just create a box that is "floating" on it. Has it been done?
 

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Discussion Starter #546
I did measure some drivers today, the B&C 12bg100 & 10NW64, Beyma 10MWnd and my sub the sbp15.
First real free air T/S (except VAS) to update my simulations in winisd.
At the end it didn't differ a lot, not obvious in the simulations, in fact it's a little better for the Beyma.
But maybe I should better try the VAS measure to get the real whole picture.

Then tried them in 20 liter and measured near field, outside, with REW & the dayton tool to get an idea on final Qtc and FR, the sbp stayed in its box (around 60L.)
It was interesting to see the Qtc, I should have tried to remove some volume with some wood blocks but I didn't really bother, it was more to get a first idea.
Both midbass Qtc are too low, around 0.37/4, they should be ok in 10L.
But even in 20L they look very similar to my actual 8mbx boxes in doors, for 10/12L., same slope (not here).
Then I played them at higher levels, it was direct from laptop to a small amp so the volume level is not super precise with this dumb new "touch bar" on mac :rolleyes:.
Here the beyma at different levels, dark green is good, gold starts to get nasty in the distortion plot.
Of course it’s nearfield so I should remove maybe 3/6db once in car at my head, but even with EQ cut it should be plenty enough.



For the subs the 12BG gave me a Q of 0.85 in 20L. unstuffed.
I tried because I had nice results in winisd, wanted to see if I could play later with Linkwitz Transform in a super small box since it can handle 1000W+ and has a solid motor.
Here in blue is the max acceptable, still outside here, no cabin gain.
I measured it in car, it gets to flat, but there’s just not enough headroom to be comfortable.
Now I know I would need a stronger sub to try LT and make any real difference.
I’m seriously looking at the B&C 15SW… reverse mount on a tiny box, this guy gave me crazy good results in simulation!
Would be cool to get the same FR than an IB15 in only let’s say a 30L. box :p
I say same FR because the rest would probably change, it may sound differently but I want to try.
If it's only a decay difference maybe it's ok in car? And I don't have much choice in this car.
The only other solution would be 4 or 6 LS10-44, in tiny boxes too, spread the bass around... But one thing at a time, let’s focus on the midbass since I have a good sub.



The sbp15 in 60L gave me 0.86, and I was surprised here because in winisd it's over 1.1.
Maybe the volume is actually bigger than I thought.
Also it's heavily stuffed, maybe too much I got some squiggling on the impedance curve, something to improve.
But I must say the box is not so clean inside after all butcher steps it went through.
But clearly for now I'll keep the sbp. It's a big damn box on my rear bench, but it works well and clean.
Especially the cone right behind me, I can almost feel it «*wrapps*» me.
Overkill a bit maybe, with measurement I can push it too much but with real music I never felt it failing, not once.
And with cabin gain I cut it a lot, zero boost.



IT's strange because with only 300W available, full range, it should not go over excursion in this box.
But here the last good curve it the purple one, under 2% distortion. Higher it gets over 10&25%.
I didn't try intermediate levels.

Well, I'm not sure I learned a lot that I didn't know.
Unless that I need at least the same sub response, will just try to get it in a smaller box.
And the midbass 10" should be plenty good in 10L. Their distortion is good at 2% up to 115db.
Bigger is not needed, it could even be smaller and still ok. Only ported would make a valuable difference, but too big too complex for me for now.

Next, I'll start to work on a baffle or a dummy box to test in car.
I'll pick the beyma, but only for its 4ohms (not really needed), and for a slightly smaller volume for a corner. But both seems all good, I could even try one of each per side :p
 

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Discussion Starter #549
Lmao.
I know I sound sniffy at times

Maybe I can pre apologize for my duschery ahead of time

It's hard to convey hard sarcasm with dickish statements
But at least I try ;) ;p
What, what you wanna say? :p
No need for pre apologiz with me man ;)
Heh, most of the time I just miss the sarcasm or irony because of my english :D



Good to see that you're still going, don't worry too much about Qtc, just EQ the response to whatever you want. My midbass enclosures are at 2.2 and they are performing great ;)
Han'! Yes I came to this conclusion too by trying. As soon as the driver accepts it.
But if 2.2 seems like a stretch!
 

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Jaguar XKR, Jbl, Audiofrog, Acoustic Elegance & iphone source.

Naaah, I had a peak of 12dB or so around Fsc (155Hz). Pulled it down 15dB and they are playing well down to 50Hz. The drawback is that you need really sturdy boxes and they get powerhungry as crap. The mids are eating more power than my 15" dvc sub >.<


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Discussion Starter #551
Re: Jaguar XKR, Jbl, Audiofrog, Acoustic Elegance &amp; iphone source.

Naaah, I had a peak of 12dB or so around Fsc (155Hz). Pulled it down 15dB and they are playing well down to 50Hz. The drawback is that you need really sturdy boxes and they get powerhungry as crap. The mids are eating more power than my 15" dvc sub >.<


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Where do you cross them?
But I have no problems with my midbass and their boxes.
Well I'd like to cross a bit lower but it's not related to the box (Q<1), but more the driver itself. I just don't think it can play strongly and cleanly there.
So it's more about the sub, and for this one it's hard to compensate for a high Q without putting thousands of watts on a beefy driver.
Car being a convertible I can't use much volume, so I try what I can to get low distortion and still high output in a different way.
The bc 15sw simulated well with Linkwitz transform in a tiny sealed box.
Just not sure the driver can accept it, in real.

So I ordered some ls10-44 to test...
 

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Discussion Starter #553
So the sbp15 didn't have much output at 20?
No no it does with cabin gain, and I just cut the 50hz bump.
It's just the size and placement that are a bit... ghetto.
Can't put my back seat to the max where I like or it can touch the surround sometime. Not much, like an inch, but it bothers me.
I just want to try something else a bit cleaner looking. Especially since I deadened the area now, I lost few cm.
Had great sounding results with 4x6", good spreaded sound but not much output.
Maybe 3 or 4 LS10 would be ok, simulated they say so.
 

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Re: Jaguar XKR, Jbl, Audiofrog, Acoustic Elegance &amp; iphone source.

Where do you cross them?
But I have no problems with my midbass and their boxes.
Well I'd like to cross a bit lower but it's not related to the box (Q<1), but more the driver itself. I just don't think it can play strongly and cleanly there.
So it's more about the sub, and for this one it's hard to compensate for a high Q without putting thousands of watts on a beefy driver.
Car being a convertible I can't use much volume, so I try what I can to get low distortion and still high output in a different way.
The bc 15sw simulated well with Linkwitz transform in a tiny sealed box.
Just not sure the driver can accept it, in real.

So I ordered some ls10-44 to test...
No highpass at all, the enclosure takes care of that. The acoustic crossover happens around 70Hz with 24dB slopes both ways. Lowpass is at 230Hz / 24dB LR.

Not all drivers like super smallish enclosures though. It helps if the speaker got low Qts and low VAS relative to size.
 

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Discussion Starter #555
Re: Jaguar XKR, Jbl, Audiofrog, Acoustic Elegance &amp; iphone source.

No highpass at all, the enclosure takes care of that. The acoustic crossover happens around 70Hz with 24dB slopes both ways. Lowpass is at 230Hz / 24dB LR.

Not all drivers like super smallish enclosures though. It helps if the speaker got low Qts and low VAS relative to size.
Ok, mine still need a 50hz/12db LP for an clean acoustic 80 or 100hz.

For the drivers, it's just that I read on some other forums that the surround could get destroyed in too small boxes on power peaks.
I'm surprised because a low QTS woofer should be more solid and accept more stress there.
But yeah maybe near the fs, even for a sub it's just too much.
 

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Not all drivers like small enclosures but I have fed my Seas L16 tons of power, exceeding Xmax even and absolutely no sign of damage after one year now. These are stiff alu cone, high quality drivers though but for the surround to be destroyed... I dunno, I believe it when I see it ;)
 

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Hi hanatsu!

Long time buddy!


So, I agree with hanatsu also, I use virtually no HPF either,
On the 10s no HPF and the 6.5s A 3db slope from 200 and some mild eq at resonance.

But let em play all the way down.

One you add the electronic HPF you also introduce time smear at crossover,
With no HPF the enclosure does it for you and below f3 it's mostly just noiseless excursion, so use mild eq to control it. Doing it that way has no "added" phase issues. Or shall I say lessened by a big degree with use of IIRs for EQ reasons.
At least it not a 90db stop band at 80hz which is such a fragile phase region

Even tho I could easily make a fir for a linear phase HPF and get better power to the driver from excursion the issue is ringing in the filter at that point.

IIRs are noisy (especially in midbass) and firs can pre ring pretty easily, a small amount of pre ring in the excursion band where there's no reinforcement is okay on midbass but why when you can easily have no worries with no HPF.

Better phase, plenty loud , no pre-post ringing , cleaner impulse in general.

Key is control excursion with eq. Find the band that moves the driver too much and makes it spitty when loud.

Try it both ways measurements and look at the shape of the IR with both. You'll see the difference
 

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Discussion Starter #559
Found some time to start on the kicks.
After long search online I got a better idea on my footwells.
Depending of years models it’s built differently.



mine is full closed in two parts


There's a cavity just before the firewall, probably more for comfort and to hold some electronics for the gas pedal on both LHD and RHD.
Lightly braced but the welding is pretty basic, just to hold them.
So I decided to cut, not much volume maybe 1 or 2 liters gained, but it will help to push further the driver, about 1".
It helps to aim them a bit more while keeping the same brake pedal clearance.
First the right side, easier and I can learn for the other side.

First with a nibbler and some aviation shears.
It's mostly 1mm but could be more in some places, with the nibbler it's ok but it's really not easy to use it in this area.
Shears are easier but couldn't always cut.




So after too many finger cuts I went to get this guy:



In 5 min I did more than in the previous 2 hours! :p
Really cool, a bit too big but the blade can be placed in 4 directions it’s super handy.

I didn't remove the whole thing because I just couldn't reach the edges cleanly and left some bracing behind.
But I got what I needed.

I didn't relocate the side connectors, they’re kind of recessed and I won't gain anything if I don't cut behind them.
Then layed out some CLD where needed, ensolite + some 1/2" heavy foam at the bottom and the side, in contact with flat panels, if it can help to isolate the final box for later resonances.
Then prepared to tape for fiberglass, for next weekend I hope.



With this 12" triangle/pyramid shape I should get around 1/4 cu ft.
Not much, but I may be able to gain more on top of the box, the dash is kind of empty behind.
But I’m not sure I could get the same amount on the left side.
And I need to keep some space for the horn driver!
 
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