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Discussion Starter #1 (Edited)
I am having trouble with my new system. I have...
(2) Boston Pro 12.4 Subs in the hatch
(2) 6.5" Boston Pro Components in the front doors
(2) 5.25" Boston Pro Components in the rear

The 4 component sets are run off an a/d/s 6-channel amp and the subs are run off a 2-channel Rockford Fosgate. I have a crossover running wires to the amps. All this is run off a Sony 910 head unit.

I used to have this system in a 97 Camaro RS. I am now installing it in my 93 Supra TT. I made templates for the fronts and rears and mounted them in the stock locations. There is a good deal less room for these speakers than there was in the Camaro.
When I hook up the system without the subs there is quite a noticeable difference in quality between how the Camaro sounded and how the Supra sounds. The highs coming from the 4 component sets sounds great, however there is virtually no bass. In the Camaro (without the subs hooked up) just 2 of these components alone would make the car shake with bass. Now with all 4, there is very little bass. There is sound coming from all the speakers and tweeters but like I said, very little bass.

Can any of you install gurus think of any recommendations what might be keeping it from sounding like it did in the Camaro? Like I said, there was a little more room for each speaker but I dont think there would be enough to make as big of a difference as there is, and again I could rattle the car with just 2 of the components. I can post pics of the speakers installed if you think it may help you.

Please let me know if you have any advise.

Thanks in advance,
Jeff

P.S. The amps are the same and are tuned the same as
they were in the Camaro
 

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Nice system. I'm using Bostons and a 6 channel ADS amp. First check that the polarity is right on the front speakers. + to +, - to -. If one side is not right then the upper bass will cancel out. You can also try switching the polarity on the sub incase it is cancelling out. The vehicle itself contributes a lot to the overall sound. It might just be the camaro had better acoustics. I had a similar problem with a hole around the crossover frequency. Ended up over lapping, letting the front midbasses play down to 33 hz and the sub up to 500 hz. 500 is too high because it draws the bass to the back but I don't have a lower chip for the crossover right now. But overlapping made a huge difference in sound quality. Just need to tune the frequency a little and everything should be good. Oh, make sure the polarity of the 2 subs is the same also. If one is backwards in relation to the other almost all of your bass will cancel.
 

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Eat a bag
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Discussion Starter #3
supra400hptt,
Cool, I think we have the same a/d/s amp. Let me ask you a question, where do you tune it??? I have set it all up and stuff but cant find where to fine tune the damn thing!!

Jeff
 

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For the tuning I was referring to my audio control crossover. It divides the signal before the amp. Bass goes to channels 5/6 which are bridged into one channel. I run just a single 12 inch sub. Are you using any crossover at all? The amp I have is the PH15. 50 x 6, but channels 1/2, 3/4, 5/6 can eached be combined. Mine is set up to run 100 x 3. I don't use rear speakers right now. The amp has no built in crossover. If you don't have one I recommend the audio control 4xs like I have.

If you want a picture of your frequency response get a CD with pink noise every 1/3 octave ("My Disk", sold through crutchfield) and the radio shack spl meter. I made a chart with the 1/3 octave frequencies, then played each while recording the spl. Plot this on the chart and you can get a visual of what you system is doing. That's how I figured out my bass problem. At around 90 hz there was a big drop. So I changed the frequency on the crossover to let the fronts play lower and the sub higher so the hole was filled. Let me know if you want to try this. I'll elaborate.
 

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Discussion Starter #6
supra400hptt,
i forgot to mention, that yeah, i do have a crossover.

What you were saying sounds good with the 1/3 octive CD. Can you please elaborate more. Drop me an email if you like...
[email protected]

Thanks a ton, it is worth a try...
Jeff
 
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The acoustics in the MKIV are not all that great. This could be the sole problem. Now let me ask ya a few questions...

What kind of sub box are you using in the Supra? Was it the same one used in the Camaro? This is really important.

I beleive the Supra's stock speakers are 5" up front and 4" in the rear correct? I would get some of Thomas Kenyons speaker templates for the front. This will increase the bass response from the front components. I beleive he has them for the rear as well. If not he will be able to make em. I highly recommend getting these.

How do you have them mounted now? Stock locations? Another big point in any system.

I think the biggest problem here is the placement of the speakers and subs. Not crossover points. If you say everything is setup the same, you should have some bass. Then have to tune it to the acoustics of the Supra. So, answer these questions for me and let me see what I can come up with. Lata.
 

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Discussion Starter #8
Well the sub box doesnt matter. I havent done that yet and am not using that to tune my components. In the Camaro, I had the subs turned off, and the components would rattle the car. So I wanted to get the components that way in the MKIV. I havent hooked up my subs yet and wont for some time (until I build a sub box)

I dont have them here, but I believe the Supra front stock speakers are 4" and the rears are 6 3/4". I am pretty sure that is what the stock are. I mounted mine with some templates that are pretty much the same as the ThomasKenyon ones (I used hardboard)
Everything is mounted in the stock location.

Let me know what you think,
Jeff
 
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AKA SIR

Jeff,

You are suffering from a cancellation problem. By this I mean the sound waves come from your components are being canceled out. When sound waves are aloud to travel backwards (away from you) and forwards (towards you) form the same location, there will be a cancelling affect. This usually affects the mid range the most, and supra's are notorious for this.

1) Make sure your phases on the speakes are in check, including rca's. Fist diconnect you rears, so only the doors are palying. If they are and the problem persists, then swap phases in the passenger door see if the sound improves. Reason being even if all is wired +to+ and -to-, speakers can still be out of phase. Stick with what sounded better. Now do the same for the rears, baypass fronts for this. NOw that you are happy with the sound balance, start again with the front speakes, slowly turn up the gains on the amp, until it feels/sounds good to you, also try swapping the phases, between pairs front=pair1 rears=pair2.

If still problem is still there try #2

2) you'll have to sound dead'n the doors, the doors on the mkiv's see to let a lot of air move back and forth in behind. You cand dead'n the whole door, or you can build a small enclosure to prevent the backwave in the door. Combine this with #1 and you should solve your phase problems.

Ps leave the subs out of the eqn until you solve your probs with the fronts. If it still persists, post back,
Jakub
 

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Discussion Starter #10 (Edited)
not to sound stupid or anything, but what are phases?

Also, if I were to build a small enclosure for the mids, it would be very small, probably just big enough to fit the magnet in. Would this be ok?

Jeff
 

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Sound travels like waves in an ocean. If two boats make waves, the waves will travel and meet. If two high points of the wave meet at the same time you'll get a peak bigger than either of the original waves. If the peak of one meets the low point of the other you'll get a smaller wave than the one with the peak. The problem can occur when you mount speakers in different locations in the car. When the sound waves meet, they may reinforce each other and cause a big peak, or may cancel each other causing a dip or diminished sound. That was the problem in my supra right at 90 hz. Can also be caused by miss wiring of the speakers. If the cone of one moves outward and the cone of the other moves in at the same time, the sound waves cancel. You can have cancellation problems both acoustically (due to where the speakers are mounted) and electrically (how they are wired). Sometimes even when properly wired (+ to +) you still have an acoustic cancellation.

I would not mount any mid or midbass in a puny enclosure. The bigger the speaker the more important it becomes. You can get away with more with a 4 inch vs a 6.5. Most of the mids and midbasses are designed to be in an infinate baffle (large enclosure like a door). I know this is a fact with the Bostons because I have them. So no, I would not put them in a small enclosure in the door. Make sure the mounting board is very ridgid (1/2 MDF or better), that the board is ridgidly mounted to the door, then sound dampen the hell out of the door. This will improve sound quality. Installation is at least as important as the speakers you select. You've got awesome speakers so the installation needs to be worked on (acoustic cancellation) or electrically there is a wiring problem. I had to play around with my crossover points to compensate for some really bad acoustical cancellation. Not the best approach but it's sufficient. I don't compete. Hope this helps a little. There are entire books written on this subject. There are some good tech papers at www.audiocontrol.com. If you get a chance read them. They are a lot better explaining things than I am and may shead some light.

Will email you later on how to plot your frequency response.
 
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AKA SIR said:
not to sound stupid or anything, but what are phases?

Also, if I were to build a small enclosure for the mids, it would be very small, probably just big enough to fit the magnet in. Would this be ok?

Jeff
Phase is the signal the speaker sees and replicates.

If a speaker is in phase, wired -to- +to+, and you swap the -/+ on the speaker, you will be close to 180 degrees out of phase.

The degrees actually vary, this the resistance, power, and a few others,====> sorry too much info, no need to confuse any more, sorry,

Hope this helps,


To calculate the need encloser for the speakers use threir theile small parameters or specs.
Good luck, and keep us updated
Jakub
 
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When you say sound deaden the doors, what do you mean? Do you mean put the sound deadener on the inside of the door, like where the speaker is mounted and shit, or do you mean on the inside behind the glass on the back of the outer door panel??? Or both? Which method works better, and I have an MKIII, so it'd be a pain in the ass to put it behind the glass. I have the same problem as AkA sir, I have a pair of Focal 6.5'' polyglasses up front mounted on some nice panels made by Thomas Kenyon's shop, and I have a PPI amp that is 80x2 rms running them. My friend has the same speakers and amp and he has ALOT more bass than me. And those 2 speakers are all he has in his car and it sounds like he's got subs. He has no sound deadener at all in his 91 accord. Would sound deading the doors help a lot or not much???
 

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Discussion Starter #14 (Edited)
Ok, here is how I am going to start....
Start with the two fronts solo (no rears) and first, make sure the + on the speaker is lined up with the + on the crossover and same to the amp (for each speaker). Assuming that they are correct, while playing music or a cd that will give good sound range, adjust the crossover to find a good frequency.
Repeat with the rears.
Dont bother building an enclosure for any of them cause the mid-woofers are similar to subs where, if they are in an enclosure that is way to small, they wont sound good... and I wont be able to build an enclosure big enough to make it worth while. So think about dynamatting the doors to sound dampen them.
Does this sound like a good start?

Questions still:
Ear Candy: you said to make sure the phases are correct for the speakers, including the RCAs. How can RCAs have opposite phasing? There is only a left RCA and a right RCA?

supra400hptt: by sound dampening the door, do you mean get some dynomat and put it on the inside of the door (behind the glass)?

(everyone): should I be running my component crossovers on flat or -3 db

Thanks for all the info guys. KEEP THE RESPONSES COMING!
 
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TITO said:
Jakub, where the hell have ya been?! :D
Hey buddy,

How have you been? I have been drifting around, but have mid terms and building up duesstt's 94 supra. He works me like a dog... I'll be around more soon


Also known as Sir...
Yes by that I mean the left right, not intended towards you, but a lot of self installers, make this little mistake.

As for you question on flat or -3db, it's your ears, how ever you like it. That is offered as an option b/c most peoples front stage is very strong, but the lower fq cant hit as hard, so they use -3db as a simple leveling agent, simple in comparison to a EQ.

Sound deadening goes on the inide part of the door that the door pannel attaches to, you can do the whole door, but it will end up breaking the hing;)
Keep us updated
 

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Discussion Starter #17
Ear Candy,
I would think that dampening a door would mean putting dynomat on the inside of the door away from you (the side of the door farther away from the driver and the side that you can not touch if the window is down)
If the purpose of sound dead'n it is to prevent the back and forth movement of air, you think you would dead'n this side cause it is behind the magnet.
The side you said (the side of the door that the speaker is mounted to) does not seem to make sense in preventing the movement of air...
Am I wrong?

Jeff
 

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Discussion Starter #18
I just realized that my crossover takes 4 inputs (R/L Front RCAs and R/L Rear RCAs) It has 6 outputs (R/L Front HIGH PASS RCAs, R/L Rear HIGH PASS RCAs, and R/L Low Pass RCAs)

The reason I am not getting any bass out of my componets (or at least part of the reason) is cause they are only powered by a HIGH PASS frequency?!?!?! Duh. I have to figure out how all this was set up before where I got good highs and lows from my components.

Any thoughts?
hmmmmmmmmmm
Jeff
 
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AKA SIR said:
Ear Candy,
I would think that dampening a door would mean putting dynomat on the inside of the door away from you (the side of the door farther away from the driver and the side that you can not touch if the window is down)
Actually the purpose of deadener, is to prevent vibration of parts and pieces that like to vibrate. Deadener is also make to absorbe musicical tones and notes. Where by it works in absorbing the back wave, and to prevent refection of the sound in the interior medium of a car.

If the purpose of sound dead'n it is to prevent the back and forth movement of air, you think you would dead'n this side cause it is behind the magnet.
The side you said (the side of the door that the speaker is mounted to) does not seem to make sense in preventing the movement of air...
Am I wrong?

Jeff [/B]
Actually diffirent installers will tell you different. I always apply it to the surfaces that will actually vibrate, or reflect unwanted sound. The prevention of air seeping in and out of the door, is what is a common prob b/c it alows the back waves to work their way into the cabin and cancel out, or mess up the phase and frequency. So you want to seal as effectively as possible, but it is not necessary to cover everypart of the door, b/c weight becomes an issue. Rule of thumb usually goes, deaden what vibrates, but if you compete, deaden as much as needed.

I confused you in preventing back waves, with sealing the door... Sorry.

They do have many things in common, but the main purpose of deadener is to absorbe sound waves, you can use it partial to seal a bit of the door, but not much. Sealing the door is to preventing back waves, from getting into the cabin.

I hope this makes more sence, if not I will clear it up as much as I can.
Jakub
 
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AKA SIR said:
The reason I am not getting any bass out of my componets (or at least part of the reason) is cause they are only powered by a HIGH PASS frequency?!?!?! Duh. I have to figure out how all this was set up before where I got good highs and lows from my components.

Any thoughts?
hmmmmmmmmmm
Jeff
Always got to double check you work, soundtest, soundtest, soundtest...

there should be an option to use a full line (single right left)speaker input to into the x-over.

Here is the answer to you question you e-mailed me about...
Anytime you place amps where you hinder their cooling ablilities ie under a seat, in the seats, in a closed off amp rack ect ect.. you will have to vent the air around the amps. This is usually done with a fan, that is set up with a relay, that turns on with the remote turn on. The best is to set it up in a push/pull system, 2 fans minimum, one pushing cool air, one pulling the hot air. It works very well if set up right.

Jakub
 
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