# Mercedes-Benz E320T, 2000 - SQ Build



## Hanatsu (Nov 9, 2010)

Hi everyone! 

Time for a new install. Had an almost year long hiatus from doing anything related to audio and suddenly I had relapse and decided to install some "basic" stuff in my winter car. Well, that "basic" system kinda snowballed into a full 7ch active install - as usual I might add...

The car is a Mercedes-Benz E320T (V6 engine with 224hp), year 2000. The last Mercedes I had, the 280E from 1993 had an automatic transmission failure and I had to let it go. With over 170k miles I got it really cheap, I only payed like $600 for it. No issues except the damn rust in doors, fenders and about everywhere. I've fixed most of it now but it needs a paintjob which I hope I can pull off myself.

The system is kinda interesting because I got a lot of the stuff for free. All the amps, subs, cables and mids costed me nothing. The midranges are cheap drivers and the tweeters come from my last install.

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*The system consist of;*

**HU & DSP;* Pioneer P99RS

**Amp 1;* MDS Classic 4ch amp (mid 90's). The MOSFETs on the amplifying stage were shot and so were a few smaller resistors. Replaced them with FETs from a spare board I had and replaced all the larger electrolytes while I was at it. The amp did [email protected] and [email protected] below 0,1% THD. At 12,7V

**Amp2;* Kenwood KAC-7203. Was working when I got it. Connections are stuff was a bit oxidized so I refurbished it some. Looks as new now. A strong [email protected] and [email protected] below 0,1%THD. At 12,7V.

**Amp3; *SPL Dynamics ICE-3500D. A real monster amp, was also working when I got it. However the amp has been mistreated, scratches all over and looks kinda ugly overall. Hid it behind the sub box so that doesn't annoy me. Never tested the output, but it claims to be 0,5ohm stable with 3200W output. At 4ohms which at I load the amp, it supposedly outputs around 700W, which is plenty. Has some kinda of clip prevention circuit which is kinda neat. It also got a PEQ control and both LPF and HPF filters.

*Midwoofers;* Audio System AS-165C. I believe they are made by Gladen. An awesome mid with crazy output. Haven't measured these yet but it's coming as soon as I get my new mic and preamp. They are mounted in stock locations with a baffle modifier. 

*Midranges;* Vifa TC9. Amazing cheap 3,5" driver. Performs like a high-end driver. Fits perfectly into stock locations on the dash corners. I have tested these previously here: http://www.diymobileaudio.com/forum...-midrange-widebander-review-measurements.html

*Tweeters;* Gladen SQX. Used in my previous Mercedes. A low distortion, great performing driver. Fits behind stock sail panels. Previously tested here: Gladen SQX System

*Subs;* Taken from a Logitech Z-5500 system, well actually two of them. The drivers are produced by Tang-Band and is very similar to the WT-644F. Very clean sounding drivers, suitable for vented alignments.

*Cables;* OFC 4ga for the sub amp and OFC 8ga for the other two amps. Battery is behind the rear seat so no lengthy cable runs. Decent looking psuedo balanced RCAs and ordinary 12ga OFC speaker cables.

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All drivers are mounted in stock location. So this is basically a somewhat steathy stock looking setup, except the sub enclosure that is. 

Goal is, like my other builds; SQ oriented systems that can get loud with low perceived distortion. The system is almost completed, took me less than 3 days to pull this install off. That's probably the quickest build in any of my cars. I will have to go back and fix a few things though, I kinda rushed the dampening in the left door and will have to remove the door panel again to fix the small but annoying rattling, probably from the vacuum hose to the central lock system. I want to measure the midwoofer anyway so I'll do the dampening and pull the driver at the same time. I also got a lot of tuning to do, it's a pretty solid tune as of now but it can get better - I hope.

I will also pull the left midrange driver and experiment with some acoustic wool behind the driver. I also need to investigate where two high Q peaks in the 4-5kHz area are coming from, they are clearly audible and annoying on some songs. So far I've concluded that it's not the speakers themselves causing it. I will hopefully shoot a few videos later on too.

My memory card containing most of the pictures somehow found its way into my uncles car. So I'm currently waiting for him to return it to me lol. Here's what I got so far on my phone;


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## Hanatsu (Nov 9, 2010)

*Building the Subwoofer:*


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## Hanatsu (Nov 9, 2010)

Installed an "Aeroport" on the inside too, was getting a bit of turbulence. Made a good difference!





Some lining around the port and a stripe to keep it in place.


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## Hanatsu (Nov 9, 2010)

Vent tuning:

You can easily find out the enclosure tuning (Fb) by checking the impedance phase, at Fb the phase is 0deg.



This shows the effects of stuffing a vented enclosure. The impedance peaks goes down in both frequency and "amplitude". It also kills some higher frequency resonances, sometimes visible in the impedance response.



This shows initial vent length (green) and (purple) after I shortened the vent.



I actually wanted to build a 4th order isobaric bandpass box initially, but my laziness got the best of me and I went with an ordinary BR box. The enclosure is a 50lit net volume with a Fb of ~34-35Hz. I only made a really quick model in Hornresp of the vented design and forgot to save the graphs.

This was the original plan, the 4th order Iso-BP box (perhaps I'll try this out with some other drivers I have laying about later):


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## Kazuhiro (Apr 28, 2015)

Very nice work on the box. I would never have considered the logitech woofers, great thrifting!


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## Alextaastrup (Apr 12, 2014)

Good you came over all your technical problems and in an installing mood now 

What about moisture/temperature withstand of these Logitech drivers? Paper cones?


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## Hanatsu (Nov 9, 2010)

Alextaastrup said:


> Good you came over all your technical problems and in an installing mood now
> 
> What about moisture/temperature withstand of these Logitech drivers? Paper cones?


Untreated paper, yeah.

Not that bad as many thinks though, used these types of cones in doors even without damage for years. Depends on how humid the climate is I guess =/


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## Hanatsu (Nov 9, 2010)

Here's where I put my amps...

Not really done here yet. I need to clean some of the wiring up. It's how it looks right now anyway.





More is coming tomorrow...


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## Hanatsu (Nov 9, 2010)

Alextaastrup said:


> Good you came over all your technical problems


Yeah... check out what my old preamp did:



Got a new one today.


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## Babs (Jul 6, 2007)

Nice! Looking forward to seeing this one shape up.


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## Alextaastrup (Apr 12, 2014)

Hanatsu said:


> Yeah... check out what my old preamp did:
> 
> 
> Got a new one today.


Which one (old and new)?

It was a catastrofy when I tried to use a microfone with built-in sound card of the DELL notebook. The range of dips and peaks were up to 12dB and the APL measurements and correction done were simply owfull. One should be very carefull with such stuff.


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## Hanatsu (Nov 9, 2010)

Alextaastrup said:


> Which one (old and new)?
> 
> It was a catastrofy when I tried to use a microfone with built-in sound card of the DELL notebook. The range of dips and peaks were up to 12dB and the APL measurements and correction done were simply owfull. One should be very carefull with such stuff.


Scarlett 2i2 | Focusrite










The old one broke for some reason but I got good warranty on the new one so I bought another one (same model). When it worked it was really clean, -130dB noise floor well above 20kHz.


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## Alextaastrup (Apr 12, 2014)

Great preamp.Strange it broke.


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## Hanatsu (Nov 9, 2010)

I got my USB stick back with my pictures now... so here goes;



Old drivers, looks half-rotten to me;









Pretty well damped stock door panel...



Interior:


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## Hanatsu (Nov 9, 2010)

Midrange drivers;







Tweeters;















Lots of space pulling wires through to the door, very easy to do.


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## Hanatsu (Nov 9, 2010)

Mid stock placement... I damped this and forgot to take pictures of it for some reason. I'll take some pics over the other door when I remove the driver later.


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## Alextaastrup (Apr 12, 2014)

Deadening of the front doors - if any stock? Are you going to strengthen them with some alu-profiles or something else?

Are there any special (technical or economical) reason for choosing Gladen?

Looking forward to see the end of this great install work.


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## Hanatsu (Nov 9, 2010)

Alextaastrup said:


> Deadening of the front doors - if any stock? Are you going to strengthen them with some alu-profiles or something else?
> 
> Are there any special (technical or economical) reason for choosing Gladen?
> 
> Looking forward to see the end of this great install work.


*I used alubutyl 4mm "Silent Coat" on the outer door metal as well as 12mm closed cell foam on top of that behind the driver. I also used liquid sealant around the speaker baffle to keep it airtight against the back. The door panel actually seals around the driver so the entire door doesn't need it be sealed. The right side door is dead-silent in terms of rattling and vibrations and the driver got full output down to ~50Hz. Amazing mids, I can push them past Xmax without much audible distortion - I will make a real test of them later... 

*I had the Gladen in my previous install and they performed great, had them laying around so why not use them? 

I will take proper pictures of the left side door when I remove the speaker.

Test here if you wanna read: TEST


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## Hanatsu (Nov 9, 2010)

Awesome... turns out that the preamp wasn't the cause of those distortion peaks. It was the microphone, the tip of the mic has come loose and causing the signal to be overloaded. Well, the mic is 6 years old and it's time to replace it.

Ordered one of these;

Sonarworks XREF 20 

Heard that the newer ECM8000 mics have worse quality than mine, this one is individually calibrated and got pretty good specs.


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## Alextaastrup (Apr 12, 2014)

True about ECM8000, but you might be Lucky anyway. 

BHW I have calibrated mine by myself using B&K specroanalyser model L2250. Works fine after 3 years. 

But there are sometimes issues with input port of the preamp (t-bone) - should be repaired soon I think (if I manage to dissemble it without distroying the whole ****).


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## Hanatsu (Nov 9, 2010)

My builds always seem to snowballing into advanced, time consuming, expensive projects... Well, I got myself another APL1 unit to put in this car. I've gotten too used to my other car to be pleased with any form of "standard" setup... and that does of course mean I need a stand-alone DSP as well. Sooo, I bought a MiniDSP C-DSP 6x8 as well. 

Another thing I might do is to mod the tweeter sail panels. The plastic grill causing the upper midrange peaking after further investigation. I'm thinking of fiberglassing them so I can aim the drivers a little better and at the same time get rid of the stock grill messing up the response.

I also caught some form of flu or something, so I won't be messing around in the garage in a few days. That doesn't stop me from coming up with awesome plans though 

Well on the "to-do list";

*Make new RCA cables between DSP, APL1 and amps.
*Properly dampen the left door
*Fiberglass the sail panels to improve the tweeter response. Maybe even trying out if some other tweeter will fit. I got a few alternatives to choose from.
*Need to build some form a rack to hold amps and the new processors.
*Clean up wiring in the trunk.
*Tuning...


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## Alextaastrup (Apr 12, 2014)

Hope you will be soon healthy again. God bedring!


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## Hanatsu (Nov 9, 2010)

Got my new microphone now. Looks great, weighs more than the ECM8000 and got a bit more quality feel to it. I really like how they supply an individual calibration file to it, saves me the trouble.



It's definitely more linear than the ecm8000 (green), especially in the high frequencies.


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## Hanatsu (Nov 9, 2010)

Pics:


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## Hanatsu (Nov 9, 2010)

Little update:

I modified the midrange speaker grills. They messed up the response, after the fix the response cleared up, much less combing now.

I also added a little more dampening wool, noticed that sound leaked out left of the instrument cluster. 













The hole was too small as seen here.



Drilled it up a little more...







Made a seal around the cone to prevent leakage from the sides.





Leakage between instrument cluster and the piece of wood there...



My favorite tool. That extender is perfect for screws near the window.













Turned out quite nice. Sounds better too.


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## almatias (Nov 16, 2012)

Hanatsu said:


> Little update:
> 
> 
> 
> ...



Great update!


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## Alextaastrup (Apr 12, 2014)

Awaiting some good news regarding this great install. Hope you've completely recovered after illness


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## Hanatsu (Nov 9, 2010)

Alextaastrup said:


> Awaiting some good news regarding this great install. Hope you've completely recovered after illness


Yeah... I'm fine now thanks 

I have been doing some work on the car. Today I made a complete brake fluid flush. Replaced rear brakes, flushed steering fluid and replaced filter. I have also flushed the automatic transmission fluid aswell as the engine oil + filters. Need to check spark plugs, differential oil and fuel filter then I've gone over as much there is... I think. I have no service history on the car so I'd like to be on the safe side and replace all fluids and filters.

I also disassembled an old build that was almost complete, my Golf mk3. The car had multiple issues it wasn't any use trying to fix it. Anyway, I pulled all the gear from that build and it's going into this car instead.

First off I'll replace the amps. The new ones are Soundstream Stealth amps. Two 4.320 and one 1.600D. They are one of a kind amps, sort of. The guy I bought them off had them custom anodized orange. 

http://www.soundstream.com/manuals/2009/SS_2009%20Stealth%20Series%20Amplifiers.pdf







I'll be using two MiniDSP 2x4, one for left and one for right. I downloaded the 4way Advanced plugin. The C-DSP is going into my main build to replace the broken Helix P-DSP.

I ordered a metal case APL1 unit and 16 preset switch I'll install somewhere.


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## Hanatsu (Nov 9, 2010)

Done a little wiring today. Waiting for my second MiniDSP to arrive so I can't connect it all together yet. Made some RCA's in the meantime...

I'll place the processors below the amps, there are almost 2" of space there. I used a little oversized ground wires, I like to be on the safe side when it comes to grounding...

See my awesome picture below


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## Kazuhiro (Apr 28, 2015)

Slick job mate! Fantastic sleeving and management.

Could you please clarify the the tuning setup with the APL1 and two minis, thanks.


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## Hanatsu (Nov 9, 2010)

Kazuhiro said:


> Slick job mate! Fantastic sleeving and management.
> 
> Could you please clarify the the tuning setup with the APL1 and two minis, thanks.


Thanks 

Well, I use the 4way-Adv plugin for the MiniDSP. That means I will be running each box mono, i.e one box for left side and one for the right. 

Signal chain will be;

HU --> APL1 ---> Left Ch Out --> MiniDSP 1
HU --> APL1 ---> Right Ch Out --> MiniDSP 2


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## Kazuhiro (Apr 28, 2015)

Hanatsu said:


> Thanks
> 
> Well, I use the 4way-Adv plugin for the MiniDSP. That means I will be running each box mono, i.e one box for left side and one for the right.
> 
> ...


Are the subs running mono off one or both the minis?

Will all of this be able to run on the laptop simultaneously?


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## Hanatsu (Nov 9, 2010)

Will be off one of the minis. Mono.

That I don't know yet lol.


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## Hanatsu (Nov 9, 2010)

Alright, a little update again.

I wanted a 0awg incoming power cable so I had to remove EVERTHING to get it in behind the panels. Took me three hours to finish all in all. Cleaned up the wiring at the same time. Also new grounds.

I got one of those hydraulic crimper tools, it can press those terminals with a force of 24 tons apparently. 









Had to drill new holes here... easier said than done. The 0awg wire required an 18mm hole.





,









Everything back together...



Old amp behind the sub. Terminal connections...


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## oabeieo (Feb 22, 2015)

Awesome build buddy ! 

I wish I could hear it


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## Hanatsu (Nov 9, 2010)

Trunk is done for now. I will install the APL unit and the two DSPs when I get all things. Connected the amps to my P99 in the meantime. Of course I made a noob fail, I connected the wrong RCAs to the amps, I had swapped the midrange and tweeter cables. 

I wondered; strange... the system sounds so different now... there's no lower midrange and it sounds so harsh. I played at high volume with the tweeters without any highpass till I noticed the sound didn't come from midrange but from tweeters. I was 100% that I had blown the tweets but they seem to be fine.



Everything installed. Using the old RCA's in the meantime though.



My favorite "gain" screwdrive 



Installed two black metal corner strips, looks a little better imo.


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## Hanatsu (Nov 9, 2010)

oabeieo said:


> Awesome build buddy !
> 
> I wish I could hear it


Thanks. I might do a video. I got dual microphones and a DLSR so I can try my best in doing a virtual listening experience.

Still, even if it's done perfectly. You are still listening to it through your speakers, headphones etc


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## Kazuhiro (Apr 28, 2015)

You can achieve a nice YouTube experience with a Nokia 808 my friend. What mics did you buy?


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## Hanatsu (Nov 9, 2010)

Here's how everything is (will be) connected.


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## Hanatsu (Nov 9, 2010)

Kazuhiro said:


> You can achieve a nice YouTube experience with a Nokia 808 my friend. What mics did you buy?


Thought of using my measurement microphones, with the calibration file they should be 100% flat.


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## Hanatsu (Nov 9, 2010)

Mids tested, see full test data here;

http://www.diymobileaudio.com/forum/member-reviews-product-comparisons/258378-audio-system-165c.html

Distortion is quite low as I expected...


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## 1fishman (Dec 22, 2012)

Looks great, subed.

I see you put dampening material on your port tube. I was wondering about the port tube on my sub box when i built it, being so thin and all. Do you think the dampening the Areo-Tube makes a difference?


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## Hanatsu (Nov 9, 2010)

1fishman said:


> Looks great, subed.
> 
> I see you put dampening material on your port tube. I was wondering about the port tube on my sub box when i built it, being so thin and all. Do you think the dampening the Areo-Tube makes a difference?


Inside a vented box there's actually higher pressure levels than in a sealed box, at Fb the pressure will be at its highest point. Several times I've noticed small vibrations in the vent itself at higher SPL using these plastic ports. Also, on several occasions I've seen high-end speakers use massive bracing around the ports. I decided a while back to test the theory that it can make a difference and I'm positive that it did. I made measurements before and after. It reduced resonances in the midbass area/low midrange by some amount and even affected harmonic distortion. I won't say it made a huge impact but it's likely audible with certain material. I'll take a look if I can find the REW file tomorrow


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## Hanatsu (Nov 9, 2010)

Got word from Raimonds that my headphones and measurement microphone is calibrated and will be sent back together with a APL1 unit. Will probably arrive next week, in the meantime I will prepare a little "rack" that holds the Mini's in place, I'll also make the wiring for the APL1 and Mini's with an added ground that will go to the HU ground - to reduce ground loop risks to an absolute minimum. Then we shall see how the system performs.

I have dampened the trunk, finished with dampening of the left door. Replaced incoming fuse holder to a 200A AGM type, I still need to fasten it somewhere, haven't figured that out yet. Pictures coming soon.


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## Alextaastrup (Apr 12, 2014)

Looks good. Awaiting further upgrade.


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## Hanatsu (Nov 9, 2010)

This arrived today:







Really fast shipping and good packaging. Thanks Raimonds!


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## Hanatsu (Nov 9, 2010)

Some dampening done:

Trunk...





... and left door:



The vacuum tube was vibrating at 78Hz, really annoying.


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## Hanatsu (Nov 9, 2010)

Crossover settings can be deceiving;




*
Measured slope: 80Hz - 24dB/oct both sides. Almost textbook LR24.*

T/A settings at the moment.



Will install the Mini's and the APL soon and get to the real tuning.

I also might replace tweeters with either the Peerless HDS or SB-Acoustics SBC29.

I found this old screenshot. I could spot 4,4% non-linear distortion in a music track, I will re-do that test with my new headphones and the APL VST active. Let's see if the audibility threshold goes down with accurate FR reproduction.


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## Elgrosso (Jun 15, 2013)

Interesting this anti-noise paste, did you "glue" the metal sheets with it? (seems a nice non-destructive approach)
Also, you just made me realize that I forgot to order the rotary switch :/


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## Hanatsu (Nov 9, 2010)

Elgrosso said:


> Interesting this anti-noise paste, did you "glue" the metal sheets with it? (seems a nice non-destructive approach)
> Also, you just made me realize that I forgot to order the rotary switch :/



The anti-noise paste is a liquid dampener. It's water based so you can work it with your hands, when it's dry it will become quite hard, almost like glass fibre putty. It's great to seal stuff with and get in areas where it's hard to put CLD etc.

...I forgot last time too, so I got two this time 


Sent from my iPhone 6 using Tapatalk.


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## Elgrosso (Jun 15, 2013)

Hanatsu said:


> The anti-noise paste is a liquid dampener. It's water based so you can work it with your hands, when it's dry it will become quite hard, almost like glass fibre putty. It's great to seal stuff with and get in areas where it's hard to put CLD etc.
> 
> ...I forgot last time too, so I got two this time
> 
> ...


Cool, is it the same kind of stuff that they use here to smooth out everything?

http://postfiles8.naver.net/20160202_183/bewithaudio_14543812480456HfbW_JPEG/22.jpg?type=w1

That would have saved me a lot fo time!


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## Hanatsu (Nov 9, 2010)

I measured my system using the APL VST. I just need to upload it to the APL1 when I've installed everything. Still waiting for the MiniDSP, there was some issue and the shipment was delayed. Should have it this week though. System sounding pretty good right now.

I did a "normal measurement" in RoomEQ to see how it looks.


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## Elgrosso (Jun 15, 2013)

No smoothing!? Wow


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## Hanatsu (Nov 9, 2010)

Elgrosso said:


> No smoothing!? Wow


I averaged it by taking multiple samples, no smoothing required


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## Elgrosso (Jun 15, 2013)

This trace look already great without the APL!
How did you measuring go? 
I should receive mine tomorrow, next week end I will try.


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## Hanatsu (Nov 9, 2010)

Elgrosso said:


> This trace look already great without the APL!
> How did you measuring go?
> I should receive mine tomorrow, next week end I will try.


That's WITH the APL though, I ran it in virtual loopback using the VST while doing the measurements.

RoomEQ and APL measures differently, I just found it interesting to see what it did to the response acquired with the "normal" method.


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## Elgrosso (Jun 15, 2013)

Hummm, so this is the result of APL vst plugin apllied to classic REW measurements? (Like 5/3-6/2 around the head).


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## Hanatsu (Nov 9, 2010)

Elgrosso said:


> Hummm, so this is the result of APL vst plugin apllied to classic REW measurements? (Like 5/3-6/2 around the head).


Almost... This is just averaged periodic noise measured in "head-space". I only cared for the overall FR without any other data so this was less troublesome...


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## Elgrosso (Jun 15, 2013)

Ok thx!
I have somehting in mind but I'm quite sure you've explained it already I'll find it.

About the APL measurements themselves, when I've seen the "fiat" map with all the points I was quite confused on the way to do it. I'm talking with Raymond about this already, but do you have a trick?


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## Hanatsu (Nov 9, 2010)

Little update..





Removed floor panels again.





Removed oem telephone.







Installed a usb socket.
















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## Hanatsu (Nov 9, 2010)

Re tuned with APL and programmed a few different curves to the rotary switch. Really nice being able to switch so quickly. Image is stable and the center focus is really good, height/width/depth all good. 

Got issues integrating the sub, can't apply enough delay to the rest of the system to attain optimal time coherency. Still waiting for the 2nd MiniDSP, will probably be able to fix it later by cascading delay from the p99 into the minis.


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## Babs (Jul 6, 2007)

Nice work!


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## Elgrosso (Jun 15, 2013)

Nice!
You can switch presets with music playing?


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## Hanatsu (Nov 9, 2010)

Yes, the unit will swap in less than a second.


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## Elgrosso (Jun 15, 2013)

Good, I really need to get one.
And what is the impact of the big wagon cabin on the sound? (I noticed that you have the sub near the middle and not in a far corner).
You don't use surround, but even I was wondering, since maybe I'll go for a v70.
Must a pleasure to work on too.


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## Hanatsu (Nov 9, 2010)

Making the board for the DSPs. Need to wait for my 2nd Mini before finishing it. Had to mod the apl1 to fasten it properly.














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## Hanatsu (Nov 9, 2010)

Elgrosso said:


> Good, I really need to get one.
> And what is the impact of the big wagon cabin on the sound? (I noticed that you have the sub near the middle and not in a far corner).
> You don't use surround, but even I was wondering, since maybe I'll go for a v70.
> Must a pleasure to work on too.



Larger cabins got a transfer function that has a gain lower in frequency than a small cabin. I got about 20dB gain at 20Hz.

V70 is the most common car in Sweden, quite easy to work with, at least the older ones.


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## sqnut (Dec 24, 2009)

Hope you're enjoying the current'build. I feel jealous when I see clean builds like yours, because I'm all thumbs . I'm a bit lost though why TA from P99+APL+Mini Dsp isn't enough?


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## Elgrosso (Jun 15, 2013)

Hanatsu said:


> Larger cabins got a transfer function that has a gain lower in frequency than a small cabin. I got about 20dB gain at 20Hz.
> 
> V70 is the most common car in Sweden, quite easy to work with, at least the older ones.
> 
> ...


I see, the longer the cabin, the longer the wavelength to be reinforced (?)
I can see that for the v70b , here in CA there're not so common (much more xc60/70).
About that did you see or better, hear, the new s/v90?


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## Hanatsu (Nov 9, 2010)

sqnut said:


> Hope you're enjoying the current'build. I feel jealous when I see clean builds like yours, because I'm all thumbs . I'm a bit lost though why TA from P99+APL+Mini Dsp isn't enough?


Hah, no APL or MiniDSP in the car yet though 

Waiting for my 2nd unit so I can finish it. At that point it will be a non issue


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## Hanatsu (Nov 9, 2010)

Done some measurements. Thought I share them for those who's interested.

Unprocessed Subwoofer Response with and without Allpass filter applied. An allpass filter is a filter that affects phase only and leaves the magnitude response pass (all signal is passed)...



Same measurement, Phase Plot.



Group Delay (which is derived from frequency response)



You can actually make a flat group delay with normal IIR processing with the use of allpass filters. Any MiniDSP can do it. Add enough filters to reach the red line then delay the rest of the system, then you got a zero delay vented subwoofer. Pretty neat.



Here you can see that an allpass filter fixes the null created by mid/sub being out of phase. It fixes the issue better than a simple polarity swap.



Less swings in the group delay with the allpass filter compared with polarity swap around crossover.



Good summing around crossover.



Variation in SPL with different measurement points... (Subwoofer)





APL IR imported into RoomEQ compared to RoomEQ RTA/PN. They measure differently, found that normal RTA is more accurate in the lowest frequencies but APL's sound power type of measurement is much more accurate above ~200Hz.



Left Midbass driver response.



Again APL vs SineSweep Avg. APL shows the true directionality of the driver, this shows that the 6,5" mid got omnidirectional output to about 2kHz. The normal sweep method would suggest the driver is usable much higher (which it isn't).



Left Mid tuning. Crossover and 5band PEQ. The crossover slopes are L-R24 as good as they can get.


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## Hanatsu (Nov 9, 2010)

Modal Response of the left mid.



Modal ringing (peaking) around 39Hz. This goes down as cabin size increases.

Modal cancellation (null) at 63Hz. This is a non-minimum phase region which can't be EQed.


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## Hanatsu (Nov 9, 2010)

From APL Workshop:

This shows the true power response of a 6,5" woofer. Proof that as midrange drivers they shouldn't be used above 2-2,5kHz.


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## Hanatsu (Nov 9, 2010)

Elgrosso said:


> I see, the longer the cabin, the longer the wavelength to be reinforced (?)
> I can see that for the v70b , here in CA there're not so common (much more xc60/70).
> About that did you see or better, hear, the new s/v90?


Nope, we have a large Volvo factory just a few miles outside the city, a few friends are working there. I don't like Volvo myself so I have like zero interest 

I only buy German cars.


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## Elgrosso (Jun 15, 2013)

Hanatsu said:


> Done some measurements. Thought I share them for those who's interested.


Very interesting!
how did you import APL workshop curves in REW?
I have some sweeps, pink & white noise too, I'd like to compare everything on the same plot.




Hanatsu said:


> Modal Response of the left mid.
> 
> 
> 
> ...


So here, and I guess on a waterfall too, can we say for sure:
- if blue&red are very closed, it's a resonance
- if blue&red are very far, it's a null






Hanatsu said:


> Nope, we have a large Volvo factory just a few miles outside the city, a few friends are working there. I don't like Volvo myself so I have like zero interest
> 
> I only buy German cars.


Check out the sound system on the new 90, seems pretty good.
I really like their speaker placement.


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## Elgrosso (Jun 15, 2013)

Hanatsu said:


> From APL Workshop:
> 
> This shows the true power response of a 6,5" woofer. Proof that as midrange drivers they shouldn't be used above 2-2,5kHz.


I wonder how the APL algorithm works (kind of hard to explain my thoughts here)

- we know that APL focuses on the Power Response.
- when REW w/ sweeps focuses on '"one axis" response (the sum of speaker to ear axis + reflections at this precise ear position).

I can understand the different goals, so the use of different algorythms.
But the available "tools" for these DSPs are the same = amplitude and phase only (am I wrong here?)

So if a boost is applied to deal with poor off axis, the on axis gets automatically boosted too.
So why don't we get more nasty peaks?

Does it mean that off axis speaker placement is a better starting point to optimize results with APL?


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## Alextaastrup (Apr 12, 2014)

APL1 gives also a possibility to control the ratio between on- and off-axis response (taking into account, of cause, actual reflections). This works more effective for bad placement of the mid and tweeters.

For this you have to make another measurement, covering the square area close to the direct sound path. 

By boosting one also influences higher frequences due to overtones, thus changing the reflections at other frequences, so everything is not so easy... Using a power domain seems to be a better solution, that is why I stay with APl.


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## Hanatsu (Nov 9, 2010)

Elgrosso said:


> 1, how did you import APL workshop curves in REW?
> 
> 2, So here, and I guess on a waterfall too, can we say for sure:
> - if blue&red are very closed, it's a resonance
> - if blue&red are very far, it's a null


1. Import the impulse response *.wave into RoomEQ.

2. The "red" is the first response that hits the microphone, the first part of the impulse response, the colors are spaced with 50ms decay each. The blue are the decayed response, the frequencies that "linger". A peak that "lingers" is a modal peak, also called the resonance point of the cabin. It's a minimum phase region and can be pulled down with EQ. The lingering waves are most prominent in the modal region, some of these might be resonances and stuff too.


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## Hanatsu (Nov 9, 2010)

Elgrosso said:


> I wonder how the APL algorithm works (kind of hard to explain my thoughts here)
> 
> - we know that APL focuses on the Power Response.
> - when REW w/ sweeps focuses on '"one axis" response (the sum of speaker to ear axis + reflections at this precise ear position).
> ...


1, There are actually nothing but amplitude and phase to describe the frequency response.

2, Yes naturally. That's why we want to use our drivers in their omnidirectional range. The tweeter will be the exception. It will always be played outside this region in the upper octave(s).

The nasty nulls created by reflections are dependent on the microphone position, multiple points will average the response so the dips are filled up by other samples. The sound power response will naturally look more flat in this application.

3, Most of the sound we hear in a car is offaxis response already. There are so many reflections we can't separate them from the direct response without a very small FFT window, this will destroy low frequency resolution. Tweeters need to be on-axis somewhat otherwise you lose too much HF content. APL is measurement system, I wouldn't say it's better or worse having midrange driver on/off axis.


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## Hanatsu (Nov 9, 2010)

Optimized my crossover points and stuff in the MiniDSP (APL bypassed in all measurements). I'm plagued by low output now, dunno how to fix this the best way just yet. It's basically the tweeter response that mess up the entire channel output, had to lower everything below 10kHz because of the crappy OEM tweeter location.

Summing at all crossover points. Means driver are in phase with each other. LR24 acoustic slopes everywhere, close to anyway...





Just check out the issues on the tweeters, first that 15dB peak at 4,7kHz and then the HF rolloff that I had to fix with a shelf filter...

EQ Settings (1 Sub-2 Mid-3 MidR-4 Tw);









Input PEQ

Sub/Mid-Ch



MidR - TW Ch



Crossovers, check out the mid crossover (80Hz HPF LR12 - 90Hz LPF BW18...) ;


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## Hanatsu (Nov 9, 2010)

I added allpass filters at multiple point to smooth out the GD plot. 



The subwoofer is completely up front even with just the left side playing. I really think smoothing out the delay response fixes a few staging issues. I ran out of processing power, not enough biquads to fix all stuff but it sounded good to me.


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## teldzc1 (Oct 9, 2009)

What's that little board with the APL1 and DSP?


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## Hanatsu (Nov 9, 2010)

teldzc1 said:


> What's that little board with the APL1 and DSP?



MiniDC. A DC/DC isolator to prevent noise get to the MiniDSP boards, they also allow to remote start. They sell them for car audio purposes.


Sent from my iPhone 6 using Tapatalk.


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## Hanatsu (Nov 9, 2010)

Fixed the wiring of the DSP board a little better... Pity it won't be visible lol. Just waiting for the 2nd unit to place there now.


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## teldzc1 (Oct 9, 2009)

Thanks for letting me know this exists!


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## Elgrosso (Jun 15, 2013)

Hanatsu said:


> Group Delay (which is derived from frequency response)


Would you consider this curves as a good start or not?
I can see on mine that the ms8 does a pretty good job of fixing GD, everything is much flatter after than before it.


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## Elgrosso (Jun 15, 2013)

Alextaastrup said:


> APL1 gives also a possibility to control the ratio between on- and off-axis response (taking into account, of cause, actual reflections). This works more effective for bad placement of the mid and tweeters.
> 
> For this you have to make another measurement, covering the square area close to the direct sound path.
> 
> By boosting one also influences higher frequences due to overtones, thus changing the reflections at other frequences, so everything is not so easy... Using a power domain seems to be a better solution, that is why I stay with APl.


I'll have to try this, the correction for on axis.
Probably much later though




Hanatsu said:


> 1. Import the impulse response *.wave into RoomEQ.
> 
> 2. The "red" is the first response that hits the microphone, the first part of the impulse response, the colors are spaced with 50ms decay each. The blue are the decayed response, the frequencies that "linger". A peak that "lingers" is a modal peak, also called the resonance point of the cabin. It's a minimum phase region and can be pulled down with EQ. The lingering waves are most prominent in the modal region, some of these might be resonances and stuff too.


So this graph is useful to detect resonances in the modal region, so based on the cabin dimensions, but no for the nulls?


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## Hanatsu (Nov 9, 2010)

20-30ms GD in the lower octaves is normal. 

If frequency response is flat GD is usually flat. In the subwoofer range, especially with ported boxes got an "additional" phase shift causing increasing group delay. It can be fixed with FIR processing or with APF as I described before. Dunno what the ms8 does to the signal exactly...


Sent from my iPhone 6 using Tapatalk.


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## Hanatsu (Nov 9, 2010)

Elgrosso said:


> I'll have to try this, the correction for on axis.
> 
> Probably much later though
> 
> ...



You see the nulls just fine 

You can view it easily if you reduce the "time spacing window" in the decay or waterfall plot. Can also be seen in the Excess group delay plot.


Sent from my iPhone 6 using Tapatalk.


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## Elgrosso (Jun 15, 2013)

Hanatsu said:


> 20-30ms GD in the lower octaves is normal.
> 
> If frequency response is flat GD is usually flat. In the subwoofer range, especially with ported boxes got an "additional" phase shift causing increasing group delay. It can be fixed with FIR processing or with APF as I described before. Dunno what the ms8 does to the signal exactly...
> 
> ...


Here's what it does for me, and then apl on top:










My understandings:
Ms8 flattens everything over 80hz, and put a negative delay on the sub (ported).
Apl ****s back the sub to almost original delay.
(it's maybe not related, but I know I played a lot with the 180 switch on the sub when I got it. I hard time to get good "low" and "high" sub bass in the same time.)

About the nulls yes it was a dumb question, well I meant is there different type of dips that can be detected here?


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## Hanatsu (Nov 9, 2010)

This can be misleading. The excess group delay displays the "excess" between the real GD and what the GD would be if the response was of the same amplitude and is minimum phase. A peak in excess group delay means the area is not minimum phase. A flat excess means that the real GD is equal to the minimum phase GD. 

The APL don't really increase delay, it reduces it but since the real/minimum phase is no longer equal the excess are peaking.


Sent from my iPhone 6 using Tapatalk.


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## Alextaastrup (Apr 12, 2014)

Anyone tried to investigate the influence of infrasonic filter on GD? I have no ported box in my present install, so eliminating this filter for a close box was just logical.


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## Alextaastrup (Apr 12, 2014)

Elgrosso said:


> Here's what it does for me, and then apl on top:
> 
> 
> 
> ...


Do you have 3 way active front? If so, delay at 5k and appr. 0,7k seem to be too big (up til 10ms). Do you have also dips in FR at these frequencies? Maybe it is worth trying to play with selection of filter orders? They might be not 100% in phase. Filters actually should not be of the same order (symmetrical). I have managed to low down GD till max 2ms at the XO points with the help of APL1, which have to be considered as quite satisfactory due to the limitation of human ears.


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## Hanatsu (Nov 9, 2010)

Alextaastrup said:


> Anyone tried to investigate the influence of infrasonic filter on GD? I have no ported box in my present install, so eliminating this filter for a close box was just logical.



It adds a few ms delay depending on slope, I don't use it anyway. If tuning freq lies around 30-35Hz there's little need imo.


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## Elgrosso (Jun 15, 2013)

Hanatsu said:


> This can be misleading. The excess group delay displays the "excess" between the real GD and what the GD would be if the response was of the same amplitude and is minimum phase. A peak in excess group delay means the area is not minimum phase. A flat excess means that the real GD is equal to the minimum phase GD.
> 
> The APL don't really increase delay, it reduces it but since the real/minimum phase is no longer equal the excess are peaking.
> 
> ...


Ok, sounds simple like that.
So i guess here I don't have so many troubles, except on sub area:




Alextaastrup said:


> Do you have 3 way active front? If so, delay at 5k and appr. 0,7k seem to be too big (up til 10ms). Do you have also dips in FR at these frequencies? Maybe it is worth trying to play with selection of filter orders? They might be not 100% in phase. Filters actually should not be of the same order (symmetrical). I have managed to low down GD till max 2ms at the XO points with the help of APL1, which have to be considered as quite satisfactory due to the limitation of human ears.


No it's a simple 2 way, 80-1800/24db.
Isn't it strange that these delays appear at typical 3 way crossover points?

(Hope you don't mind the hijack here Hanatsu)


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## Alextaastrup (Apr 12, 2014)

No, it is not strange due to reflections and mutual cancelling.


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## Alextaastrup (Apr 12, 2014)

Hanatsu said:


> It adds a few ms delay depending on slope, I don't use it anyway. If tuning freq lies around 30-35Hz there's little need imo.
> 
> 
> Sent from my iPhone 6 using Tapatalk.



Right. In my case there was more than just few ms. I wanted therefore just to suggest avoiding this infrasonic filter (if possible)


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## Hanatsu (Nov 9, 2010)

Alextaastrup said:


> Anyone tried to investigate the influence of infrasonic filter on GD? I have no ported box in my present install, so eliminating this filter for a close box was just logical.




Analyzed 2nd order and 4th order subsonic filters at 25Hz. Adds quite a lot of delay actually...


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## Hanatsu (Nov 9, 2010)

Here's how minimum phase corrections work:



In the first picture, the gap between the actual GD and minimum phase is large, the excess delay corresponds to the gap seen between the peaks at 25Hz.



The actual group delay was lowered to the minimum phase peak and the excess is almost flat. This is minimum phase corrections, in a supposed minimum phase region. If excess GD is flat then actual group delay will be flat once the magnitude response errors are fixed with a normal EQ.


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## Hanatsu (Nov 9, 2010)

Elgrosso said:


> Ok, sounds simple like that.
> So i guess here I don't have so many troubles, except on sub area


Seems like no correction at all is done in LF region by the APL for some reason. How does the frequency response look before/after?


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## Elgrosso (Jun 15, 2013)

Hanatsu said:


> Here's how minimum phase corrections work:
> 
> The actual group delay was lowered to the minimum phase peak and the excess is almost flat. This is minimum phase corrections, in a supposed minimum phase region. If excess GD is flat then actual group delay will be flat once the magnitude response errors are fixed with a normal EQ.


Great thanks, and non minimum phase areas are can only be corrected with acoustic treatment/speaker placement etc?


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## Elgrosso (Jun 15, 2013)

Hanatsu said:


> Seems like no correction at all is done in LF region by the APL for some reason. How does the frequency response look before/after?


Right, nothing at all. 
but I just created some new target with 100ms window. And they appear to have much more impact in the sub area, I'll load them in the apl later.
(Raymond explained me again I didn't need to remeasure with different windows, could just recalculate )


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## Hanatsu (Nov 9, 2010)

Yep. Non MinPh areas are nulls only fixable by moving speakers in relation to seated position and/or room treatment. Could also be bad crossover design.

The IR is the same but the window the software calculates the fft from is different 



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## Hanatsu (Nov 9, 2010)

Ok. My 2nd MiniDSP has been sent. Will get it early next week. I've put this car in my garage over the summer. I need to fix rust and re paint half the car. I have more work as rebuilding sail panels and also make a new subwoofer enclosure. I'll complete the DSP installs and tune it ASAP then I will sporadically update this thread when I get something done.

My former main build has been on a hiatus for two years. The car has just been sitting since November 2014 and I never completed the system. I basically had to take a large break from this hobby and temporarily lost all interest. Since that interest obviously has returned, I'll be using that car again now I will focus on that after I've installed the DSPs and tuned the system.

The things I will be doing is;

*New sail panels, maybe new tweeters like the Peerless HDS or Scan-Speak 6600. Got both "on the shelf".

*New subwoofer, I really want to make a 4th order BP. I got two JBL GTO12D2 for this. Nothing wrong with the current, I just feel that sealed/vented is a bit... boring. Everyone uses those.

Anyway I'll be returning to this thread this month. It's a bit cluttered in the last pages but I think I can clean it up with some new material 

http://www.diymobileaudio.com/forum/build-logs-project-install-gallery/144986-vw-passat-b5-2000-sql-build.html


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## Hanatsu (Nov 9, 2010)

Finally my 2nd MiniDSP arrived. I'm a bit confused though, the paint is matte and not glossy. Also the power connector is different, no connector was supplied either, wtf? Well, I hope it works.





I'll install it soon and tune the system.


Sent from my iPhone 6 using Tapatalk.


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## Elgrosso (Jun 15, 2013)

Strange, these are the regular 2x4? I thought you had the HD


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## Hanatsu (Nov 9, 2010)

Nah I thought about the HD for the other build. Got the c-dsp instead. Heard the HD had issues...


Sent from my iPhone 6 using Tapatalk.


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## bmwpowere36m3 (Mar 20, 2008)

Always a pleasure to look at quality builds…


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## Alextaastrup (Apr 12, 2014)

And quality writting!


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## Hanatsu (Nov 9, 2010)

Thanks guys!

I'll be installing the DSP board this weekend then this build gonna have a hiatus for a while. Late summer/autumn I'll be building a new sub (4th order BP with one or two JBL GTO 12"). New fiberglassed sail panels, new tweeters (SB Acoustics SBC29). I'll be focusing on finishing my other build in the meantime


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## Hanatsu (Nov 9, 2010)

Ok, I've installed everything and I'm basically done. I only need to mount that USB extension I made somewhere. My plan with cascading the output delay from the HU failed. I dunno how I thought, it's simply not possible given the amounts of I/O I've got in the MiniDSPs. 

I use outputs from both MiniDSPs to sub amp (same settings). The APL measurement system refuse to work properly otherwise. It only measured with sub active on left channel and messed up the correction curve completely.



Color coding the RCA's, stole that idea from someone here...



One for the APL1, one for each MiniDSP. I flipped the third USB socket around so I know which is which 



Tuned it somewhat. Staging is good but the curve need some work. I'll come back to this later.


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## Babs (Jul 6, 2007)

Nice and tidy! Looks great! Like the color-coded RCA wire-ties. 

To reiterate, so you're running the APL1 for LR single pair, out to two MiniDSP's then? 

I'd like to read up what troubles I think you mentioned on the FIR-based Mini's.. I've been told FIR = typically big budget hardware.

Would like to see APL get into a multi-channel full DSP with TA, XO's etc to go with that cool EQ.


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## Hanatsu (Nov 9, 2010)

APL1 is before the minis. Left output from APL to one Mini, the right output to another.

This allow equalization of the entire signal with 2ch


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## Elgrosso (Jun 15, 2013)

Nice, so your USB cable does not stay in?


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## Hanatsu (Nov 9, 2010)

Lol, the USB cable was only connected during tuning 


Sent from my iPhone 6 using Tapatalk.


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## Elgrosso (Jun 15, 2013)

Hanatsu said:


> Lol, the USB cable was only connected during tuning
> 
> 
> Sent from my iPhone 6 using Tapatalk.


Of course, I meant why didn't you install 3 cables to the front seat?
So always ready for tuning, no back and forth to the trunk.


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## Hanatsu (Nov 9, 2010)

You can't extend these USB cables too far, need an amplifier if more than 3m or so. It's a good idea - might do it later, I simply don't have time right now ;(

Wonder if it's possible to connect all to an USB hub?

Sent from my iPhone 6 using Tapatalk.


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## Elgrosso (Jun 15, 2013)

Hanatsu said:


> You can't extend these USB cables too far, need an amplifier if more than 3m or so. It's a good idea - might do it later, I simply don't have time right now ;(
> 
> Wonder if it's possible to connect all to an USB hub?
> 
> Sent from my iPhone 6 using Tapatalk.


Ha ok, I wondered that when I installed mine, but it works fine.
One disadvantage of the wagon then


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## Hanatsu (Nov 9, 2010)

Here's some of the measurements I did... Haven't run APL yet.

This displays the processing of a simple MiniDSP though. I focused on getting the stopband of the crossovers right, since the APL system is 2ch it's one thing you need to fix beforehand for optimal summing between drivers. These are almost perfect 24dB L-R slopes, at least on the lowpass side.



I just flattened the response out some. Don't like that peak at 4-5kHz, again that's due to the tweeter OEM grill, pretty crazy huh? It's possible to EQ it but I'd like to fix it properly later.



Ran a quick run with APL and detected a null between mid and midrange. Fixed T/A and added allpass filters for flat delay. Fixed that peak at 1,5kHz that didn't show up at all during "normal" measurements! APL does detect things that otherwise goes unnoticed in some ranges. Doing 1-3kHz by ear is almost impossible.





I got the absolute best summing by adding two allpass filters, one at 60Hz and one at 78Hz on mid. Small dip at 70Hz but the drivers sum very well in the passband otherwise.


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## Hanatsu (Nov 9, 2010)

I used allpass filtering because, if you T/A left-right mids to attain a center, both sides will no longer sum perfectly with sub. With APF it's possible to add just enough delay at a specific frequency - attain the center and great summing between all three drivers.


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## Alextaastrup (Apr 12, 2014)

APF is a rather interesting approach. Need to go deep with this item. How you did it? With minidsp software? Is it possible to delay just left front, not a single speaker? How much? Are there any limits?


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## Hanatsu (Nov 9, 2010)

Alextaastrup said:


> APF is a rather interesting approach. Need to go deep with this item. How you did it? With minidsp software? Is it possible to delay just left front, not a single speaker? How much? Are there any limits?


http://www.diymobileaudio.com/forum/technical-advanced-car-audio-discussion/259201-advanced-filters-allpass-lt-etc-minidsp.html


You program a biquad in MiniDSP software. Not aware of any limits. You can put the APF on the input or on a single speaker or both. In the lower frequencies there is no problems reaching 20-40ms with a mid Q filter.


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## Elgrosso (Jun 15, 2013)

Hanatsu said:


> Ran a quick run with APL and detected a null between mid and midrange. Fixed T/A and added allpass filters for flat delay. Fixed that peak at 1,5kHz that didn't show up at all during "normal" measurements! APL does detect things that otherwise goes unnoticed in some ranges. Doing 1-3kHz by ear is almost impossible.


Do you mean you adjusted manually on Cdsp based on measurements from APL? (200hz & 1,5khz)
if you have more curves, and time to post, don't hesitate!


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## Alextaastrup (Apr 12, 2014)

Hanatsu said:


> http://www.diymobileaudio.com/forum/technical-advanced-car-audio-discussion/259201-advanced-filters-allpass-lt-etc-minidsp.html
> 
> 
> You program a biquad in MiniDSP software. Not aware of any limits. You can put the APF on the input or on a single speaker or both. In the lower frequencies there is no problems reaching 20-40ms with a mid Q filter.


Thanks,

Does it mean that with the help of APF it is possible to exceed the TA max limit stated in the manual for miniDSP?


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## Hanatsu (Nov 9, 2010)

Technically, yes. You can add immense delay if you were to cascade some filters.


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## High Resolution Audio (Sep 12, 2014)

Although the technical side of everything that you post is beyond and above my comprehension, I still find myself reading and analyzing every graph and post. I'm hoping that I get subliminal knowledge through association.


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## Elgrosso (Jun 15, 2013)

Elgrosso said:


> Do you mean you adjusted manually on Cdsp based on measurements from APL? (200hz & 1,5khz)
> if you have more curves, and time to post, don't hesitate!


Quoting myself 
Hanatsu, what's your process with the C-dsp now?
I tried to optimize C-dsp first, levels, xo, ta, rew eq, rew again etc, to get the hang of the "manual" thing.
It's a lot and I canget confused or mess up things.
And even if it's fun, that's looong.
So quickly I tried the APL, and everything got better in 5 min


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## Hanatsu (Nov 9, 2010)

Elgrosso said:


> Quoting myself
> Hanatsu, what's your process with the C-dsp now?
> I tried to optimize C-dsp first, levels, xo, ta, rew eq, rew again etc, to get the hang of the "manual" thing.
> It's a lot and I canget confused or mess up things.
> ...


Process? Like how I set it up?

1. Bypass APL

2. Measure one driver at a time, all other muted, no processing applied. All levels set to -10 (for headroom).

3. With all drivers measured, set crossovers. I usually got for 24dB/oct LR acoustic slopes. I re-measure to check that the corrections were predicted correctly by RoomEQ. 

4. Apply EQ to individual drivers.

5. Set levels.

6. Turn on two drivers on the same side to check that they sum at crossover, set T/A. Repeat for sub/mid, mid/midr, midr/tweet. Then do the same for the other side.

7. Set up your center with correlated pink noise.

8. Run TDA, optimize any issues you may find.

9. Run APL Workshop. Check overall curve, check L/R balance. Use the input EQ of MiniDSP to adjust the curve and L/R balance so it tracks better with the intended curve in APL.

10. Run APL Workshop again, remove bypass. Done!


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## Hanatsu (Nov 9, 2010)

High Resolution Audio said:


> Although the technical side of everything that you post is beyond and above my comprehension, I still find myself reading and analyzing every graph and post. I'm hoping that I get subliminal knowledge through association.


Just ask if there's anything you don't understand


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## Elgrosso (Jun 15, 2013)

Hanatsu said:


> Process? Like how I set it up?
> 
> 1. Bypass APL
> 
> ...


Great!
So I'm good for 1 to 5.
But #6 I didn't know how to proceed, so I started 6,7&8 all together in TDA directly. Probably not the easiest.
Nice point about #9, so far I didn't use the DSP input EQ.
Is it to "double" the house target, or just for small balance adjustments?


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## KrautNotRice (Nov 2, 2015)

Very neat wiring, just like in your other builds! I love the mini gain screw driver LOL


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## Elgrosso (Jun 15, 2013)

Hanatsu said:


> 6. Turn on two drivers on the same side to check that they sum at crossover, set T/A. Repeat for sub/mid, mid/midr, midr/tweet. Then do the same for the other side.


I'm kind of stuck on #6.
Left woofer & mid and right mid & tweeter don't sum.
So I tried with TDA, adjusting slowly TA on the cdsp, but no luck, it's easy to get stuff slightly better for two drivers, but really worst for all.
what kind of adjustement should I expect to do, few 0.01, 0.1, 1 ms?
What is your process exactly here? Adjsutment/sweeps to check, adjustment/sweeps to check etc?

At the end I just the APL, and it fixed a lot!


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## Hanatsu (Nov 9, 2010)

Dependent on wavelength, if there a null at 50Hz for example. 1/50=20ms. 360deg is 20ms at 50Hz so 180deg is 10ms. Fixing a null at 50Hz requires 10ms T/A.

At 200Hz, 180deg shift equals 2,5ms.


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## scuxxio (May 18, 2016)

nice info


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## Elgrosso (Jun 15, 2013)

Thanks! 
ok so for:
- 80Hz / 12.5ms > 6.25ms to invert, 0.08ms per degree
- 300Hz / 3.33ms > 1.66 ms to invert, 0.009 per degree


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