[darcness]

As the title says I'm getting absolutely horrible break up near the top end of my 6.5" RSD woofers. It's coming on right around the 1k and up range, peaking right around 2k and absolutely killing my sound.

I've had these exact speakers in my old car (Regal) in doors that were not treated and they didn't exhibit any of this breakup. The doors in my GTI are much more solid, and I'm using the exact same baffles I was in the Regal, made of 3/4MDF. My crossover points are the same as they were, 80Hz-2KHz for the 6.5's and 2.5KHz and up for the tweeters. Also, I've tried EQing the higher end of the 6.5's down a bit and it's not really helping. It's almost like the break up isn't volume or EQ dependent, but rather a constant.

I'm beginning to suspect my gains. I just did some very small adjustments to them last night and I think I may have brought the drivers into clipping. Any other suggestions to fix this problem would be GREATLY appreciate. Quite honestly, I'm at a loss for why it's happening.

 

[60ndown]

u sure they're in phase?

 

[darcness]

99% sure but I'll check again. I ran all new speaker wires myself and made sure to mark everything to make install easy and correct. I'll have to go back and make sure I didn't mark something wrong or hook something up incorrectly, but like I said, I'm 99% sure they are wired in phase.

Edit: Just for reference, the midbass is amazing, just the higher end that REALLY starts to crap out.

 

[60ndown]

maybe turn the tweeters off and listen to just the mids, and then just the tweets?

are the mids 'broken in' ?

over powering?

what x over you using and is it working normally ?

both mids breaking up or just 1 side?

have you tried raising the x over point?

drivers sealed perfect against baffle?

im sure its just something minor you have missed, no reason the drivers should be so different to all the rsds people rave about.

unless their fakes? or blown?

 

[Oliver]

All vehicles are not the same !

What have you tried as far as open celled foams , deflex pads ,etc..,

Do you think it is reflections ? early , late

Towels on dash , windows ... any change in sound , same ?

CMusic's tuning tutorial is a progression for bringing a system to its' fullest potential, do it ... do it again ... rinse and repeat

 

[Jopop]

I have exactly the same problem. But i also have it with a different driver..

See this very long thread..

http://www.diymobileaudio.com/forum/showthread.php?t=43286

 

[darcness]

maybe turn the tweeters off and listen to just the mids, and then just the tweets?

are the mids 'broken in' ?

over powering?

what x over you using and is it working normally ?

both mids breaking up or just 1 side?

have you tried raising the x over point?

drivers sealed perfect against baffle?

im sure its just something minor you have missed, no reason the drivers should be so different to all the rsds people rave about.

unless their fakes? or blown?

Speakers are broken in.

I'm running a PPI 630IX that has channels 3+4 and 5+6 bridged to the mids (30x6 @ 12v rated).

Xover is on my DSP and it's a 4th order @ 2KHz, tried changing it lower and higher, still breaks up.

Both sides break up.

Drivers are sealed via foam ring to the baffle, baffle is sealed via silicon to door.

All vehicles are not the same !

What have you tried as far as open celled foams , deflex pads ,etc..,

Do you think it is reflections ? early , late

Towels on dash , windows ... any change in sound , same ?

CMusic's tuning tutorial is a progression for bringing a system to its' fullest potential, do it ... do it again ... rinse and repeat

I used cmusic's guide faithfully and it's what got me the excellent sound in my Regal. I used it again with the GTI and everything sounds great, except the break up.

I think it may be reflections. I need to do some more testing, but if the break up goes away with the windows up (as opposed to down behind the driver) then you may be on to something. I thought of this as well, just didn't have time to test it as I had to get into work and I was running late already.

I also turned off all other speakers (sub and tweeters) and the break up is definitely only on the mids.

Just as a note, the speakers are installed very far back in the door on this car. The tweeters are in the sails, 180 phase from the mids to bring the sound together. The mids are installed in the bottom of the door almost all the way back (towards the back seats). I know this location isn't ideal, but could it really cause the break up?

Hopefully this helps. Thanks so far guys.

 

[Mr Marv]

I had a similar problem recently and it turned out to be a problem with the gain pot on the amp. In my case the midbass seemed OK but upper frequencies sounded "garbled" when the gain was in one certain position. After going through all the checks described here I found that if I moved the gain one way or another it sounded fine!

 

[Oliver]

Deflex pads behind the speakers [might allow you to play them louder whilst deflecting the energy to the sides ], not allowing the pressure wave to bounce back to the cone and cause concentric and radial break up modes.

 

[darcness]

I had a similar problem recently and it turned out to be a problem with the gain pot on the amp. In my case the midbass seemed OK but upper frequencies sounded "garbled" when the gain was in one certain position. After going through all the checks described here I found that if I moved the gain one way or another it sounded fine!

I too am thinking it's the gain setting. I don't remember hearing this break up for the first couple days I had the install done. I only adjusted the gains last night to get a better balance between my tweeters and woofers. I'm thinking I will turn the gains on all the speakers down a bit and try that.

The thing is, I run my gains very high. Not because of the volume, but because I'm using a non-amped SB Live 5.1 sound card as my source unit. I bet I'm running around .2v on my RCA's. I know I'm setting gains correctly, based on my input signal voltage, but could this be causing some sort of issue?

 

[Jopop]

Does it sound kinda like a chainsaw?

Try either hooking them up to a different amp or try running them unbridged.. i.e. low power.




Anyways, can you post some pics of your setup? You might have some funky horn loading effect going on if its mounted the way i think it is.

 

[satsloader]

I'm gonna throw this out there, discard as needed..

What if the DSP was at fault, that is what if for some reason it wasn't attenuating the freq's above the cutoff? The only thing that would lessen the problem then would be lowering gain. I know the DSP failing is improbable, but it's the only reason I can think of.
If you have a way to measure frequency, like in the $100 RTA thread, etc., you could measure and verify whether your crossover was indeed filtering the high end at or around the point your setting, and watch it increase or decrease as you adjust the crossover point.

I just looked at 60nDown's list again.. I'd run through it, again if necessary, as it covers my hunch as well as a bunch more possibilities..

Muting/unplugging the tweets and listening while adjusting is a good first step if you can't RTA it..

One other thing you can try, unbridge your channels, re-wire if needed, and test using the possible alternative hook up schemes.. This for diagnostic purposes, obviously when you eventually figure out the cause you'll want to re-bridge..

Good luck, and remember, it's always the last thing you do that fixes it.

Bill in P.G.

 

[60ndown]

"I'm running a PPI 630IX that has channels 3+4 and 5+6 bridged to the mids (30x6 @ 12v rated)."

30x6?

30 watts is not a lot of power,

im guessing your clipping the signal,

do the drivers break up in upper frequencies at lower volumes?

i bet not...= clipping.

 

[Oliver]

I too am thinking it's the gain setting. I don't remember hearing this break up for the first couple days I had the install done. I only adjusted the gains last night to get a better balance between my tweeters and woofers. I'm thinking I will turn the gains on all the speakers down a bit and try that.

The thing is, I run my gains very high. Not because of the volume, but because I'm using a non-amped SB Live 5.1 sound card as my source unit. I bet I'm running around .2v on my RCA's. I know I'm setting gains correctly, based on my input signal voltage, but could this be causing some sort of issue?

It's all tradeoffs and yes ! some aren't worth it !

 

[darcness]

Well, I don't have any actual pics of the drivers installed, here's a shot of my door with speaker locations.

In the pictures you can see where the stock 7" is located near the back of the door. The tweeters are in the sails, and the stock midrange are actually mounted on the door skin. I bypassed the mid, which I'm sort of regretting now. If I can't fix this break up, I may end up trying the stock mid for a 3 way setup, then if I like it, getting a better mid and going fully 3 way for first time.

Anywho, I removed the stock 7" and then removed that plastic mount. That left me with a 7" (approx) hole in the door. I then used a 3/4" MDF baffle and affixed that to the door, then affixed the 6.5" to that. Sealed the speaker to the baffle with foam tape, and then the baffle to the door with silicon.

 

[darcness]

"I'm running a PPI 630IX that has channels 3+4 and 5+6 bridged to the mids (30x6 @ 12v rated)."

30x6?

30 watts is not a lot of power,

im guessing your clipping the signal,

do the drivers break up in upper frequencies at lower volumes?

i bet not...= clipping.

Remember this is 30x6 at 12v. Also I'm bridging it as well. I'm guessing I'd be some where in the nature of 100watts to each mid. I would think that's enough...

 

[bbfoto]

darcness,

It's most likely your sound card and/or your amp clipping since they are probably both MAX'd and/or what Marv suggested regarding the gain pots. Check this first as suggested.

Obviously, .2 Volts on your Line-Level RCA's is quite low, especially if this is at or near Maximum on your volume control.

Also, what software are you using to play your music files? Are you using the EQ in the software? IME with many software music players (WinAmp, etc.) I have found that activating the EQ in the player will TOTALLY distort the music/output!

Your best bet if you are sticking with the Computer as the Source is to go with a USB DAC, and I would suggest the "Bloat USB DAC" from www.hippohifi.com . You can read reviews of this DAC over on www.mp3car.com ...just do a search. I can't remember the output voltage spec off-hand, but I believe it is in the ~2-Volt range.

The main advantage to this unit as opposed to other USB DACs or Sound Cards is that it has a Higher Output Voltage. It was initially designed as a High Quality USB DAC/Headphone Amp for headphones that are difficult to drive from standard outputs (such as computer/soundcard headphone minijacks.)

The owner will add female RCA outputs for an additional $10 or so (the standard unit is built with a 3.5mm stereo mini-plug used for most headphones.) This option is not listed on the Web Site, but he will add almost any type of connection that you request when you order or email him. There are also a bunch of "upgrade" electrical component options that you can order for the Bloat DAC. It's not cheap at $200 for the basic unit, but from reviews of CarPC users it seems to be VERY good in the SQ department! I am still waiting for mine to arrive so I cannot comment personally on the SQ, but I trust most of the reviewers that have commented on it.

Hope you can figure out your problem since it seems it wasn't an issue when you first completed the install. Again, as Mr Marv suggested, reset your gains lower or to where you had them before.

 

[Oliver]

BBfoto , excellent post !!!

 

[darcness]

I'm using FreeIce to play my music. It's based off windows media player, and I wouldn't dream of using a built in EQ so no worries about that.

I use Kx drivers for my sound card and have been since I installed the PC in my original ride. I use the Kx DSP for all my processing, including the EQ's, crossovers, and T/A.

I'm also a regular over at mp3car.com. I've been on that site since I think 2004, and I agree, TONS of useful info for us CarPC users over there. It's the place that first got me in to CarPC's in fact. I've heard great things about the hippo hifi dacs and most likely will upgrade to one soon.

I just think it's really clipping as you and others have said. It didn't exhibit these issues when I first installed it and this is the only thing I can really think of that I changed. I'll adjust the gains tonight and report back with my findings. I really appreciate all the help.


EDIT: Bingo guys. Certainly it was the gain, most likely causing clipping. I just went out and adjusted it a bit and sure enough, good clean sound again. Woohoo! Thanks all for the help. Now I can get to installing my newly received CAI.

 

[60ndown]

woot!

now go get a better camera.