Bi-amping and Audiolense/REQ

[Krunok]

@Krunok - a bit more info here including pics and timing (step) response: https://www.avsforum.com/forum/113-...audio-subwoofer-thread-1223.html#post57390652

Your system is really impressive and obviously extremely well tuned! Still, I can't find info how you measured the repsones you've shown, so can you please clarify?

And to your other q's see my response in the other thread on Room eq's dos and don'ts. PS. I don't bother with measuring both speakers at the same time as John M, author of REW) (and other practitioners) have explained why, but my poor brain can't remember at the the moment and I can't find the link...

I have seen many discussions on this topic, some in favor of measuring bth speakers at the same time to evaluate response up to 300Hz, some saying it's not neccessary. I would very much appreciate if you can find the link and post it , preferrably in the "Room EQ, do's and dont's thread".

 

[Olli]

Ok Mitch, I get it. You secretly updated your subs!

 

[Krunok]

Ok Mitch, I get it. You secretly updated your subs!

Yep, he did - probably with steroids.

 

[josh358]

@Olli Yes, I can confirm in Acourate and Audiolense that the simulations match the measured in REW perfectly - done it over a dozen times in both programs and don't even bother any more.

Agree with the downward slope or tilt of 20 Hz to -10 db @ 20 kHz provides the most neutral response in my experiments. And seems to agree with the R&D that Floyd Toole and Sean Olive have performed, which I wrote a summary, peer reviewed by Sean Olive: The Science of Preferred Frequency Response for Headphones and Loudspeakers.

Here is the measured response of my system at the LP using default REW settings with a 500ms right window:

View attachment 22675

Aside from constant directivity horn equalization, this was taken before I used partial correction to 8 kHz. For some waveguides and compression driver combos, I find leaving the top octave alone sounds less strident, as does using a very small value (e.g. 1) for HF excess phase correction. Then the HF eq is acting more like a tone control.

Hope you have fun in your new space!

The link to your summary doesn't seem to be working?

 

[mitchco]

Thanks @josh358 I fixed the link in the post, and here it is again: The Science of Preferred Frequency Response for Headphones and Loudspeakers. I was fortunate that Dr. Sean Olive peer reviewed my article.

 

[hvbias]

@March Audio for full featured DSP software, both are best in class. If using digital XO capabilities, Audiolense gets the nod as the time alignment process is fully automatic, and repeatable, whereas in Acourate it is a manual process. Given Acourate's manual process, introduces variability in time aligning drivers, especially for subs, as the wavelengths are so long. OTOH, depending on one's needs. Acourate has more raw audio DSP functions whereas Audiolense has a more automated workflow for most common use cases, including digital XO and time alignment.

There are a few idiosyncrasies between the two wrt target designers and slightly different proprietary psychoacoustic filtering, but the end results are top notch for both. Audiolense can lower low frequency group delay and cancel the first major room reflection... While Audiolense has multiseat correction capabilities, I rarely use it as both Audiolense and Acourate use special psychoacoustic analysis algorithms that does not require multiple analysis measurements. Both low frequency correction and time alignment remain solid across a wide listening area based on a single analysis measurement. I show in my book how the low end correction and time alignment remain the same across a 6ft x 2ft listening area with 14 separate validation measurements.

Both can do partial correction to any frequency. If using full range correction, the number one mistake people make is over correction at high frequencies, which leads to harsh top end. If using constant directivity waveguides, in a digital XO scenario, as is the case for me, then some level of constant directivity horn equalisation is required. However, I leave the top octave alone and let the compression driver and waveguide combo do its thing and always sounds better to my ears. If using full range correction, it is best to reduce the amount of correction in the high frequencies so the correction is more like a sloping or tilting "tone control" so one can adjust the amount of high frequency energy coming at you to taste.

Hope that helps.

Do you have any plans for a second edition of your book which includes Audiolense information? Preferably a print edition

 

[mitchco]

Hi @hvbias Yes, a 2nd edition is in the works and will include Audiolense and other software DSP program info. It is slow going at the moment as I am helping my partner with her book to be released in the next month or so. Btw, there is a print edition available. Click on my sig and then select paperback.

 

[hvbias]

Hi @hvbias Yes, a 2nd edition is in the works and will include Audiolense and other software DSP program info. It is slow going at the moment as I am helping my partner with her book to be released in the next month or so. Btw, there is a print edition available. Click on my sig and then select paperback.

Thanks, I actually do have both the ebook and print for your first edition, I just wanted to see if you'd be doing a print edition for your second edition, that is my preference when it comes to reading books

Is the Audiolense support/member forum as active as Acourate's?

 

[mitchco]

Yes to both Bernt (Audiolense) and Uli (Acourate) are quality folk - their DSP software products are well supported with active forums.

 

[josh358]

Thanks @josh358 I fixed the link in the post, and here it is again: The Science of Preferred Frequency Response for Headphones and Loudspeakers. I was fortunate that Dr. Sean Olive peer reviewed my article.

Thanks -- looking forward to reading it! That's about as august a peer review as you could have.

 

[DonH56]

I just got MItch's first edition, hope I have time to read it before the second comes out! Thumbing through it I am anxious to spend more time with it and hopefully implement it in my own system. Of course, I have to somehow slow down Life and Work issues first...

 

[josh358]

I just got MItch's first edition, hope I have time to read it before the second comes out! Thumbing through it I am anxious to spend more time with it and hopefully implement it in my own system. Of course, I have to somehow slow down Life and Work issues first...

Heh, I've had it (and Acourate) for an embarrassingly long time.