2016 Audi S6 SQ build

good job. Checks all the boxes. I'm a big fan of stacked ring MDF boxes, this is a great example of one. I like the use of materials and finish. Particularly the two subwoofer enclosures.

Your curve is 12 dB up with a super abrupt bass reduction. I'll bet you can solve your muddyness by making the bass transition smoothly from, like, 70-400. Then adjust that overall 12 dB gain up or down to suit the right sound. Then fine tune the frequency cutoffs and gain until it's right. That's just a 'guess' on my part, but I'm willing to bet it'll help.

Couple questions. What's hanging below the rear sub box in the pic? And what does it look like from the bottom? Looks like maybe a plexi bottom to the box? can see inside? Second question, do you worry about passengers kicking the front sub? Did you not consider a design feature that was strong enough and sturdy enough to be kicked and used as a foot rest without impact to the performance?
 
Whiterabbit said:
good job. Checks all the boxes. I'm a big fan of stacked ring MDF boxes, this is a great example of one. I like the use of materials and finish. Particularly the two subwoofer enclosures.

Your curve is 12 dB up with a super abrupt bass reduction. I'll bet you can solve your muddyness by making the bass transition smoothly from, like, 70-400. Then adjust that overall 12 dB gain up or down to suit the right sound. Then fine tune the frequency cutoffs and gain until it's right. That's just a 'guess' on my part, but I'm willing to bet it'll help.

Couple questions. What's hanging below the rear sub box in the pic? And what does it look like from the bottom? Looks like maybe a plexi bottom to the box? can see inside? Second question, do you worry about passengers kicking the front sub? Did you not consider a design feature that was strong enough and sturdy enough to be kicked and used as a foot rest without impact to the performance?
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Thanks for the advice! I was hoping that the 12db elevation from 200hz down to 70hz was smooth enough, but I'll play around with making a more gradual transition. As for the rear sub box, you might be referring to the carpeted bottom of the box, including carpeting around the fiberglass enclosure around the subwoofer itself, as it's dimensions are actually taller than the box. This was a design decision to keep more overall trunk space. Luckily, the box volume still easily meets the sub requirements. As for the front box, the face is made of birch ply, and is plenty sturdy as a footrest. I've since added a grille to protect the speaker itself.
 
olys6 said:
I have been having issues with some muddiness in the midbass, especially around 80-90hz. I'm currently playing with crossovers to try to keep the 4 different speakers that can provide bass signal from stepping all over each other. Right now I have my JL10W3 in the rear crossed 25hz-50hz, the front 8" Audiofrog sub crossed 60hz to 110hz, and my front door woofers crossed from 125hz to 300hz. I'd appreciate any constructive input on approaching this problem, whether it be advice or pointing me to any links. I've been really happy with the front sub bringing the bass up front, although my sub-bass seems to pull to the rear a bit regardless of me playing with phase angle or time alignment (different issue, but all part of the bass reproduction).
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Do you have your rear sub time-aligned? I believe, since that source is typically the furthest from your ears it should not have time alignment applied to it. That way, it becomes the reference and delaying everything else makes them arrive at the same time as the rear sub if that makes sense.
 
Forgot to add... regarding your crossover slopes, I've read a lot of folks are moving towards 24db/octave slopes in automotive environments where electronic crossovers are employed which helps with phase and positioning issues when using 12db/octave slopes. This is discussed ad-nauseum on the web, but here is a snippet that explains it in layman's terms from the Kicker website;

24dB/octave
Fourth-order filters have a 24 dB/octave slope. A 24dB/octave crossover with −6 dB crossover point andflat summing is also known as a Linkwitz-Riley crossover (named after its inventors). Butterworth isanother choice in this crossover implementation.
A 24dB/octave slope has the potential for a lower crossover point and increased power handling fortweeters, together with less overlap between drivers, reducing unwelcome off-axis effects. With lessoverlap between adjacent drivers, their location relative to each other becomes less critical and allowsmore practical installation possibilities.
 
Thanks guys- I've been able to make a few adjustments. First, yes, I've been using 24dB/octave crossovers for all channels. I experimented, with36dB/octave out of curiosity, but I had significant drops in multiple areas. I've been able to get a more gradual drop from 70hz to 400hz, with roughly the same 12dB drop. Also, my rear sub is now crossed at 50, with my front 8" sub crossed from 60 to 110, and my front door woofers crossed from 120-300. Bass tracks (specifically anything with a double bass) now sound much more realistic and without the resonance/muddiness that I'd been hearing.

Separate question- I've been reading up on differential rear fill, and working on applying it- currently, I have Focal woofers in the rear doors that are crossed from 70hz - 300hz (sadly, response falls off badly above 300hz). I have the left side playing 50% L and -50% R, and the right side playing 50% R and -50% L. The volume of both speakers playing is about 10dB lower than the the full system curve. I have both speakers delayed 25ms more than the front mids. A few tracks seem to have a bit of an echo effect. I'll play with shortening the delay a bit, but would I be better off using full range speakers to be able to obtain the 'bigger room' effect? Or have folks been able to replicate a larger soundstage using 6" woofers?
 
mumbles said:
Do you have your rear sub time-aligned? I believe, since that source is typically the furthest from your ears it should not have time alignment applied to it. That way, it becomes the reference and delaying everything else makes them arrive at the same time as the rear sub if that makes sense.
Click to expand...

Thanks- I've been reading up on time alignment and how to apply it using the automatic time alignment feature in the helix software- I've tried playing with it, but need to figure out how to get the software to 'see' my microphone and take readings. All I've managed to do with this feature is accidentally erase all of my distance measurements! Thankfully the software has a rewind feature to back up to earlier versions of the tune. I'd love to learn how to do time alignment correctly using REW or similar, but the videos/tutorials I've found haven't been as easy for me to follow. Apparently you first need to take impulse measurements of each speaker, so I need to figure out how to do that. Hopefully I'll find a resource on it. Any advice on finding a good thread/tutorial/video would be greatly appreciated.
 
olys6 said:
A few tracks seem to have a bit of an echo effect. I'll play with shortening the delay a bit, but would I be better off using full range speakers to be able to obtain the 'bigger room' effect? Or have folks been able to replicate a larger soundstage using 6" woofers?
Click to expand...

I believe full range speakers bandpassed are the excepted practice as long as we are not talking about some kind of co/triaxial... you dont want high frequency queues coming from behind you as it will pull the soundstage back. Your 6" woofers should be fine.
Below is a good thread that discusses rear-fill. For what its worth, some people suggest differential while some recommend not limiting the channels at all. Everyone seems to agree that the end effect depends on your ears and lots of experimentation. Also, the GotFrogs user in that thread is Andy Wehmeyer from AudioFrog... he knows his stuff;
https://www.diymobileaudio.com/threads/optimizing-differential-rear-fill.366761/
 
olys6 said:
Thanks- I've been reading up on time alignment and how to apply it using the automatic time alignment feature in the helix software- I've tried playing with it, but need to figure out how to get the software to 'see' my microphone and take readings. All I've managed to do with this feature is accidentally erase all of my distance measurements! Thankfully the software has a rewind feature to back up to earlier versions of the tune. I'd love to learn how to do time alignment correctly using REW or similar, but the videos/tutorials I've found haven't been as easy for me to follow. Apparently you first need to take impulse measurements of each speaker, so I need to figure out how to do that. Hopefully I'll find a resource on it. Any advice on finding a good thread/tutorial/video would be greatly appreciated.
Click to expand...

Most DSP software allows you to input time delay numbers in either actual distance measurements or in milliseconds, but regardless, you still have to eventually break out a measuring tape to come up with the numbers. @ErinH has a site that does the conversion for you;
http://tracerite.com/calc.html

Like I mentioned earlier, figure out which driver(s) are the furthest from you ears and make them the reference (don't apply T/A to them)... then align all other sources by applying T/A.

Remember that T/A should be done after gains, crossovers and RTA's have been done as a fine tuning of the sound stage. The pinned threads from this link are some good sources for the initial setup steps;
https://www.diymobileaudio.com/forums/how-to-articles-provided-by-our-members.5/
 
mumbles said:
Most DSP software allows you to input time delay numbers in either actual distance measurements or in milliseconds, but regardless, you still have to eventually break out a measuring tape to come up with the numbers. @ErinH has a site that does the conversion for you;
http://tracerite.com/calc.html

Like I mentioned earlier, figure out which driver(s) are the furthest from you ears and make them the reference (don't apply T/A to them)... then align all other sources by applying T/A.

Remember that T/A should be done after gains, crossovers and RTA's have been done as a fine tuning of the sound stage. The pinned threads from this link are some good sources for the initial setup steps;
https://www.diymobileaudio.com/forums/how-to-articles-provided-by-our-members.5/
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Great! Thanks for all the advice.
 
Thanks, no, I'm not nearly that talented. My upholstery guy out here in Olympia does meticulous work. He did my dash and door cards as well over the past year and half.
 
I actually stumbled across your build thread on Audizine where you mentioned Hydes, so thank you for supplying the info here as well!
 
mumbles said:
I actually stumbled across your build thread on Audizine where you mentioned Hydes, so thank you for supplying the info here as well!
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You’re welcome- both vendors are very responsive- make sure you ask for various samples of different shades for eaxh type of material- I found that what I see on my screen and what arrives at the doorstep tend to be off by a shade or 2 (screen usually a shade darker than the actual material).
 
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