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What is the difference between the APL TDA and APL Workshop software? Thanks.

EDIT - Nevermind, found my answer.
http://www.diymobileaudio.com/forum/2606098-post85.html
Right. Workshop can not give you a picture in a time domain. But stabillity of APFR results is simply impressive. On the contrary , TDA will present the system response to the sweep signal in only one point (typically - listening position). TDA gives a possibility to see both channels and sub playing simultaniously.

Both are great measurement tools, but you need also a measure to make delays. In this case DSP's which are available on the market (for the car application) are limited to 10-21ms. This might be not enough for a complicated sub enclosure, placement of a subwoofer in the trunk, etc.

By using additional program from Acoustic Power Lab, called ConeqC1 it is possible to make a delay from 0 till 4,979ms as many time as you wish. Just browse to find necessary FIR filter on your PC, chose required time delay and save it as a backup. Next time - use this as a new FIR filter and so on.
 

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By using additional program from Acoustic Power Lab, called ConeqC1 it is possible to make a delay from 0 till 4,979ms as many time as you wish. Just browse to find necessary FIR filter on your PC, chose required time delay and save it as a backup. Next time - use this as a new FIR filter and so on.
Wow I need to try that, I still didn't play with C1 yet! (So many things to do...)
So you add delay to the APL filters?
 

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Exactly. And checked this wirh TDA. IIt works.

Sendt fra min GT-I9505 med Tapatalk
 

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Do we need to have nul as a main goal when making TA?

Head movements are around 5cm during driving. There is also a limit for threshold at different frequencies. Are these things audible below let say 5msec? Used almost 3 hours yesterday trying to press delays down to nul. Managed about 3,5msec (incl. subwoofer in the trunk), 0,3msec above 600Hz. Your opinions, please?

Frequency (Hz)* Threshold (ms)* Threshold in T*
(periods or cycles)
8k Hz* 2 ms* 16 T
4k Hz* 1.5 ms* 6 T
2k Hz* 1 ms* 2 T
1k Hz* 2 ms* 2 T
500 Hz* 3.2 ms* 1.6 T


Are there any info about threshold values below 500Hz?
 

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I think I have read it, but can not remember figures below 200Hz.

2D 100ms_PNG.jpg

Results of my last TA tuning - front should be first delayed by appr. 45 msec before I could make fine-tuning.
 

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I think I have read it, but can not remember figures below 200Hz.

View attachment 135417

Results of my last TA tuning - front should be first delayed by appr. 45 msec before I could make fine-tuning.
Seems very nice, sub and woofers are within 1ms or so no? Why did you say 3.5ms?
Did you adjust all this with C1? (If I remember you have a passive 3 way)

For the threshold around 20hz I read about 30ms is acceptable, some says much more.
I don't know what to think of this, since I can clearly hear smaller differences there.
But I now have two subs (front and rear) so it's maybe more the different summing that I hear, or something else (eq?).

About the head movement/placement, did you try TDA in different points?
I may try, just like left ear/right ear to compare to the centered point, to see the difference before I optimize it "too much".
 

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Yes. Tried left-right. But was more interested in moving the mic up-down. Lower position of the mic. makes the difference between the woofers and mids less. But again my height coud not be changed as the placement of woofers in the front doors. Not in this install at least. So I have to live with it.

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Yes. Tried left-right. But was more interested in moving the mic up-down. Lower position of the mic. makes the difference between the woofers and mids less. But again my height coud not be changed as the placement of woofers in the front doors. Not in this install at least. So I have to live with it.

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Less when you lower it? in mine it's the inverse, the dash mask mid/tweeters.
Just gave me the idea to try a bottom limit to the mic movements during APL "painting".
 

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Discussion Starter #176

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Thanks a lot

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Dear Friends,

Please take a look on Jack Regula`s paper:
https://soundforums.net/forum/pro-audio/product-reviews/205223-a-new-way-of-looking-at-speakers-and-rooms-review-of-apl-tda

And some announcement.

Acoustic Power Lab (APL) has become SynAudCon sponsor! It is well-known training company among audio engineers and sound system professionals. SynAudCon offers practical and relevant education through their in-person seminars, online training, member’s forum, and their online educational library.
Celebrating this event we want to share our joy with our clients and we have fantastic gifts:
SynAudCom membership opens the door to a wealth of audio information and provides unlimited opportunity for connecting and collaborating with thousands of industry professionals. It also includes: member’s forum; over 500 technical articles on audio and acoustics; intensive field studies; RIR exchange; member directory.
And the most valuable present is a chance to attend training course at SynAudCon. All the detailed information will be given individually.
(Simply make an order for any of APL products and get your present! )
Please contact APL to get your free SynAudCom membership or to attend training course at SynAudCon. (Prospective customers will have preference.)
Notice: the present amount is limited!
Also, to support an education and in conjunction with this event, APL is offering APL TDA software’s individual license for student’s license price for one month.
 

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Great article.

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With regards to the method of using TDA. Since it is measuring frequency arrival times, why do we need to ensure that both L and R frequency response should be close or within 3db? A higher or lower vol does not change each frequency arrival time right?

I asked, as I am still testing if APL1 would be worth investing. I have purchased the softwares including the VST for use in my home office system.

So if L/R frequency balance is important, I would have no way to see if TDA can make any further improvements in my car system or see if I can use TDA to improve on my cars delay timing?
 
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