DiyMobileAudio.com Car Stereo Forum banner

1 - 10 of 10 Posts

·
Registered
Joined
·
4 Posts
Discussion Starter #1
I'm a bit of a noob in audio, I'm hoping someone can help me understand...

I had stock head unit, aftermarket amp and 4 door speakers (components in front, coaxial in rear doors) installed by a shop several years ago. No subwoofer.
When that was done I had fun reading sounddeadeningshowdown and following everything there, so I pulled out my interior and did 25% coverage CLD, MLV/CCF everywhere, etc.

Recently stock head unit died, have put in a sony instead. In general audio seems better, but now I'm noticing so muddiness/inaccuracy in the bass.

Reading on hear about muddy bass, and I see a couple common remedies to try first in the sound deadening category (which suits me as I've done that type of thing before so confident I can try it again)
1. foam rings to keep the sound going through the door panel instead of sideways, plus the foam diffuser behind the speaker
2. (more) sealing of the inner door skin.

Both seem to have the intent to prevent reflected sound waves canceling the forward ones.

I'm confused though, if I already have an MLV curtain in that door, wouldn't that effectively block mid-bass waves trying to come forward? Would would an additional barrier do that MLV doesn't?
 

·
Registered
Joined
·
104 Posts
Well I for one did more than 25% cld coverage. Probably closer to 65% outer door skin and 90% inner door skin with CCF covering 95% inner door skin. No MLV and my mid bass hits. Wouldn’t add anymore MLV but would add more CLD. I just added a set of those Speaker gaskets made out of CCF and didn’t notice any improvement. How did you set gains after new headunit? Seems like it’s not a door issue with sound deadening if you only changed out the headunit.
 

·
Registered
Joined
·
7,863 Posts
You need to narrow down the cause of the muddiness first. Is if from the speaker itself? From the signal coming from the head unit? Do you have a HPF set for the mids? Are you playing them too low? Is the distortion from resonance in the door panel?

Can you turn off all other speakers (use EQ to attenuate the tweets as much as possible, if they are connected to passive crossovers)? You want to identify the exact problem before pulling the car apart and running the risk of breaking panel clips and making the problem worse. Muddy/inaccurate bass isn't a particularly helpful description to get much help. Narrow down the problem first, and report back.
 

·
Registered
Joined
·
1,042 Posts
may also want to describe what you did or didnt do with settings and gains from the swap from OEM head to aftermarket head unit. What model Sony did you install? What settings on the head unit have you adjusted as well?
 

·
Registered
Joined
·
4 Posts
Discussion Starter #5
Thanks everyone,
System is a Chevy HHR (4 door wagon)
Audison SR series 65wx4 amp (I don't know the settings on it as I wasn't the installer - will have to figure out where the knobs are, standing on my head I could only see the plugs)
Hertz speakers (component front, coaxial rear) (I can lookup the model... I have it hear somewhere I'm sure)
no sub.
Was: stock head unit into Audiocontrol LCQ-1. Installed by car audio shop, looks like rears were turned down a bit from fronts, both fronts and rears > 1k were turned down, but more attenuation on the rears (all likely trying to smooth out the stock unit speaker levels I assume)
Now: Sony XAV-AX1000. Only fiddling with the headunit EQ, nothing on the amp. Removal of the LCQ-1 of course.

I sound deadened the car soon after the original install, doors, floor, walls, roof
Alphadamp CLD 25-35% coverage
CCF-MLV-CCF sandwich everywhere. Basically whatever I learned on sounddeadeningshowdown is what I did

Tonight's sound investigation:
I put on some acoustic upright bass which I like for not only some bass with body & punch, but also some character/timbre to listen for detail.
I used the EQ on the sony to reduce the tweeters (I found the EQ only goes down to "-6" (dB? mystery units?) so couldn't really completely remove it.)
I started with everything 1k and above as far down as it would go.
Using the fader, I found the fronts sound great, like there really was a guy standing outside my car playing the bass.
The rears sounded like he was standing inside a 50 gallon drum, kinda boomy bass, couldn't hear the character of the wood body & strings
Back on the EQ, notching 125 & 250Hz all the way down greatly improved things, the character started to come through again, though didn't mitigate all the boom from it,
with the notch still in place, the fronts still sounded much better.

Thanks for your ideas, hopefully describing audio is like describing wine, I probably didn't use the right words but you get my meaning.

Oh, and I have a frequency sensitive rattle in one rear panel anyway, so I'll opening at least one door regardless!

Thanks for your thoughts
 

·
Premium Member
Joined
·
8,999 Posts
There are a couple simple "tuning" features of your head unit I would take a look at first.
  1. Make sure "EXTRA BASS" is set to "OFF"
  2. Raise the Rear speaker High Pass Filter to 120Hz (the highest setting).
  3. Set your 125Hz and 250Hz EQ bands back to flat. (Probably best to do all bands to give you a fresh start.)
  4. Check your Front High Pass Filter and make sure it isn't too high or too low. (80Hz is a safe bet for most components, but depending on what you have you may go as low as 60Hz or 50Hz.)
  5. Set your Fader all the way to the front (15).
  6. Move the Fader back toward center until you get the best blend F/R. (You don't want the rear speakers to distract or make your staging/imaging out in front of you fall apart.)
  7. Set your Balance at center and make small adjustments L/R to get the acoustic center where you want it.
  8. Listen and measure (if you can) and make your EQ adjustments.
That isn't likely to fix everything, but I would be surprised if you didn't hear a significant improvement. If you are still having issues you may have to dig deeper into the install, or consider implementing the crossovers on the amplifier. In fact, you might want to check what those settings are before you jump into the steps listed above. Setting the amp crossovers to FULL will turn them off. You may find for the rears, using the amp High Pass Filter around 300Hz (in lieu of or in combination with the head unit HPF) will give you even better results.
 

·
Registered
Joined
·
7,863 Posts
I'm not clear on whether or not the OP has a HPF set for the mids at all, they may be playing fullrange, which could certainly cause this issue. OP if no HPF is set, turn it on, and start around 80hz, raise it until the problem goes away, if you reach around 120hz and the problem is still there, then it likely isn't related to the HPF, and you will probably want to consider putting it back down to 80hz.
 

·
Registered
Joined
·
4 Posts
Discussion Starter #8
Thanks rton20 and gijoe,
I'm not sure the sony has crossover controls independent front vs rear. The manual just says this:
Crossover Adjusts the cut-off frequency and subwoofer phase. High Pass Filter Selects the cut-off frequency of the front/rear speakers: [OFF], [50Hz], [60Hz], [80Hz], [100Hz], [120Hz]. Low Pass Filter Selects the cut-off frequency of the subwoofer: [OFF], [50Hz], [60Hz], [80Hz], [100Hz], [120Hz]. Subwoofer Phase Selects the subwoofer phase: [Normal], [Reverse].

There is a passive crossover in the front doors for the tweeter vs mid, I don't know what its specs are yet.

Like you say rton20, I now need to dig the amp out from under the seat and open the cover to look at the current settings, as this was originally installed and tuned by a shop and that amp seems to have several setup options.
Will also double check HU settings. I took a picture of the EQ screen, but not the crossover one.
I can't get to it tonight but hopefully tomorrow. Stay tuned!

From your recommendations, am I correct in understanding the opinions:
  • HPF of 50/60/80Hz for front door speakers, because the size of those mids won't do well with lower bass notes?
  • HPF of higher level (as high as 300Hz) for rears, to mitigate whatever poor performance I'm getting, but otherwise no reason to reduce bass so much in a rear door?
Regardless, I need to see if the amp has any filters turned on and report back.

Oh, and reviewing my photos from when I was in there, I note that the rear doors have no gasket of any kind on the front of the speaker toward the door panel. But the fronts do. Would it be a good idea to mitigate that?
What's the best way, some thin stick on speaker gasket on the front surface/outer edge of the speaker,
or perhaps using sticky CCF around the sides of the speaker to create a cylinder (like those pre-cut cylinders of open cell foam I see on amazon, except it would be CCF)
 

·
Registered
Joined
·
4 Posts
Discussion Starter #9
Update:
I should have looked at the amp first...
Original setup was done by an audio shop, they put in the amp and nice mid+tweeters in front. Leaving stock speakers in rear. Later I found someone selling matching model coaxial speakers that I put in the rear doors. I didn't change the amp settings at that time.

Original amp settings:
Front: amp gain = "4"; HPF 60Hz
Rear: amp gain = "5"; LPF 5000Hz

amp gain in quotes because there are no units. I don't know if the gain was needed to be higher in the rears due to the stock speakers?
And since the intent seemed to be to have highs & mids in the front, bass in the back, but I don't know the value of a 5k LPF.

For now I've made the silly assumption that the same line/same brand of speaker might be similar, so have set both amp gains to "4"
I've also reduced the LPF to 1kHz.
HU filters are FULL, since they don't have front/rear differences.
I then adjusted the fade to listen to fronts only, then to where I could tell the rears were there, then within that range backed off until it felt like the front lows were supported by bass. I couldn't get it perfect, some tracks still stand out with bass behind me.
EQ is mostly flat, trying the demo ones I like a little boost of 2-5k, but kept bass flat for now.

I'm not getting the "boomy" bass as much now.

In all this experimentation I'm still finding that I have a fair amount of vibration in the rear door panels or thereabouts, so I think I'll work on that too.
 

·
Premium Member
Joined
·
8,999 Posts
Update:
I should have looked at the amp first...
Original setup was done by an audio shop, they put in the amp and nice mid+tweeters in front. Leaving stock speakers in rear. Later I found someone selling matching model coaxial speakers that I put in the rear doors. I didn't change the amp settings at that time.

Original amp settings:
Front: amp gain = "4"; HPF 60Hz
Rear: amp gain = "5"; LPF 5000Hz

I've also reduced the LPF to 1kHz.

I'm not getting the "boomy" bass as much now.

In all this experimentation I'm still finding that I have a fair amount of vibration in the rear door panels or thereabouts, so I think I'll work on that too.
I would change the rear crossover settings of your amplifier. Switch it from LPF to HPF and bring it down to the 300Hz range. I'm betting that will eliminate a lot of your vibration. You can also try dropping it lower and find the balance between what sounds best to you and where driver movement starts exciting the surrounding panels.
 
1 - 10 of 10 Posts
Top