Acoustic Horn Design – The Easy Way (Ath4)

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There I did it....lol...tuned to 500hz...one peak filter and a low shelf....0.3mm xmax left on the table...for the Axi that is but I digress...

I think it was probably something I read from JMLC about the group delay...


I still am skeptical...the FR I have in HR is not like I see in the graph for the 2380a...

It works tuned at 600 too....I proved myself wrong...

THis is modelling for the Axi2050 though....The driver in the Strauss would have less displacement....
 

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This group delay on the lower end of the passband of the device itself you often hear about is totally irrelevant. It is tied to the amplitude response of the device and the final group delay is given by the final acoustical response (and the crossover as a whole). I don't know who originated this notion but it's a complete nonsense.

I dont know what to say to this other than, I'm sure I came to this notion after reading about the perceptibility of group delay? Aren't we to be under 2-3ms by 100hz for "Ideal"? Thats JMLC speak I'm sure.
 
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I'm glad to be wrong about that...When you say shape it...what do you mean...Looking at a 400hz 2order XO of the above, group delay barely moved....

Long story short I thought I was some sort of rebel or rule breaker by letting my group delay peak above 1ms at such a high frequency (330hz in my case I think I hit 3ms)...you are making it sound like it is a non issue

If we are talking about linear phase correction...thats something else...the Strauss doesn't use linear phase...I've also been trying to design around minimum phase.
 
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Long story short I thought I was some sort of rebel or rule breaker by letting my group delay peak above 1ms at such a high frequency (330hz in my case I think I hit 3ms)...you are making it sound like it is a non issue
No, it's not a non issue at all. For example in your previous picture the resonance around 300 Hz is pretty nasty and should be corrected in the crossover filters. But that's the point - do whatever you need in the crossover (as long as it's reasonable). If you shape it for a smooth high-pass response, there will be no group delay left to worry about.
 
camplo, use EQ cut instead, drop the level to around 90dB line where the 16kHz is at ;)
What frequency is the low knee now? Low knee shouldn't be so steep now so less group delay?

Hold on//let me think about this before I confuse myself lol....I know you are thinking to use a low shelf up high...thats not going to help the knee..HornResp filter Wizard wont let me see above 1000hz anyway =(
Placing a low shelf above the knee (I tried at 5000hz) and lowering it only makes the cutoff steeper but the knee does not change much in its location as far as frequency
 
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No, it's not a non issue at all. For example in your previous picture the resonance around 300 Hz is pretty nasty and should be corrected in the crossover filters. But that's the point - do whatever you need in the crossover (as long as it's reasonable). If you shape it for a smooth high-pass response, there will be no group delay left to worry about.

You and Ro808 just took me to school....Thank you for that lol

Still...this peak in group delay...focusing on its effects on SQ....its trivial you're saying? Just fix Fr and call it a day>?
 
camplo, use EQ cut instead, drop the level to around 90dB line where the 16kHz is at ;)
What frequency is the low knee now? Low knee shouldn't be so steep now so less group delay?

As you wished
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This is a highshelf @ 212hz and low Q

I will say that the EQ you use to try implement this stuff IRL is crucial...I couldn't get my low/high pass shelves within my eq to mimic some of the stuff I've done in HR or else where.
I wonder if I tried a low shelf when I meant to try a high shelf...and then there are the Q values...and types of shelfs, whether low or high...
 

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I will say that the EQ you use to try implement this stuff IRL is crucial...I couldn't get my low/high pass shelves within my eq to mimic some of the stuff I've done in HR or else where.
I wonder if I tried a low shelf when I meant to try a high shelf...and then there are the Q values...and types of shelfs, whether low or high...
As long as you use minimim phase stuff only (typically via IIR filters, which I heartily recommend) the only thing that really matters is the final total response. All the ways to get there will end up in the same amplitude and phase/group delay response. The same response as with good old passive filters, BTW (or active analog for that matter).
 
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