New loudspeakers & room digital correction service

[pkane2001]

2 hours ago, fresponse said:

Those convolvers are not compatible with our technology because there are of "one to one" type : this means that left channel is convolved with a filter and send to left output. Same goes for the right channel. What we need is left channel convolved with 2 different filters with respective output sent to left & right channel. This is why I mentioned the butterfly plugin which offer such flexibility (a filter set = 4 different filters)

 

Very interesting! So, is the HQPlayer convolver fully compatible with the filters you produce? Does the cross-talk reduction work with HQP?

 

You mentioned a free trial. How do I request this, once I have the necessary measurements?

 

I've been using REW to build a set of filters for quite a while, but would like to see if your filters can produce an improvement over what I've been able to do. Can you also supply these filters as REW EQ files, or only as impulse response?

 

 

[pkane2001]

3 minutes ago, wgscott said:

If that level of care and compatibility goes into the website, a cynic might conclude the same might hold for the actual software.

 

That's harsh. I would give this new venture the benefit of the doubt and judge on the merits of the product, rather than by how well the website is crafted.

 

I had the same problem from an iOS device, but no problems from MacOS Safari or Chrome.

[pkane2001]

2 minutes ago, Jud said:

I think the idea isn’t that Bill has come to a conclusion about a product he hasn’t tried, but that a user’s experience on this commercial site is something fresponse should be concerned with.

I get that. As someone who has started numerous ventures where web presence was not the primary product, I can tell you that it's hard to get it right on the first try. Often, time and money is spent on the product with website being an afterthought. I'm sure the website will be fixed in time, the problem has already been reported.

[pkane2001]

1 minute ago, mansr said:

If the web is your primary, or only, sales channel, a quality website should bloody well be your top priority. This includes working with all reasonable browsers as well as passing compliance tests.

 

Wow, give these guys a chance! They just introduced a new product a few days ago that might have some exciting applications in my system. I'd much rather discuss that than what browsers don't render their website particularly well.

[pkane2001]

A question to @fresponse: Will you be able to accommodate a house curve, and if yes, in what format?

[pkane2001]

6 hours ago, fresponse said:

@pkane2001 : our goal is to propose the optimal filters set by default. But if you have some preference in terms of tonal balance we can adapt to different kind of house curve format (text file, picture) The process is to start by our proposal and iterate if it is really mandatory 

 

Thank you. I would definitely want to start testing with an optimal, flat filter. But, my experience flattening the frequency response did not produce the best results. A very slight house curve (a few dB bump below 70Hz and a few dB gradual roll-off after 5KHz) made a big difference. I'll do some measurements and contact you to do a test with a sample track.

[pkane2001]

13 hours ago, fresponse said:

Just to be clear when I said "optimal" I didn't mean "flat" : as you said optimal refer more to what will sound natural in your listening environment. Looking forward to your measurements !

  

Understood, that's why I said 'optimal, flat', meaning optimal and flat, as opposed to optimal and (house-)curved, which I may want to try later

 

Just sent you the measurements. Looking forward to trying out the filters!

[pkane2001]

On 7/28/2017 at 1:02 AM, sixman said:

So has anyone tried this? Has it worked out?

 

I'm in the process of testing. I'll post my findings soon.

[pkane2001]

Impressions

Over the past month, I had a chance to evaluate the service provided by Thierry of HomeAudioFildelity. Thierry offers to create custom convolution filters tailored to your own system and listening space. Two sets of filters are available, depending on your price preference: one with the ability to reduce cross-talk, and the other without this capability, but still tailored to your system to improve phase and frequency response.

 

https://www.homeaudiofidelity.com/

 

(Please note: any the theory included here is based on my understanding. If anything is misstated, the fault is entirely my own)

 

I was particularly interested in the cross-talk reduction version of the filters. I’ve been a long-time user of REW and manually created and optimized convolution filters that have been in my system for a long time (way before I even had a PC-based system).

 

Cross-Talk

What is the cross-talk reduction and why is it important? Well, the theory is that recorded stereo sound when played back over stereo speakers causes mixing, or cross-talk, from left to right channel and from right to left. This is unnatural, since ideally anything recorded in the left channel should only reach the left ear, while anything recorded in the right channel should only reach the right ear.

 

This clearly does not happen when playing music over speaker systems, since some of the sound from left speaker reaches the right ear, and some of the right channel sound reaches left ear. The theory goes that this produces a less natural sound, with less clarity and a more confused soundstage image. Note that this does not happen when listening to music over headphones! There are much more complex solutions that have been proposed to solve this problem, but most require a very tiny sweet spot, or involve complex head tracking algorithms that are as expensive as they are hard to implement.

 

For this reason, when Thierry offered his service, I jumped on it. While his filters promise some cross-talk reduction,  all of cross-talk cannot be completely eliminated with convolution filters.

 

Conclusions

Thierry was very helpful, patient, and provided great support during my trial. I can highly recommend that you try his service, especially the free evaluation he offers. I do suggest that you pick music that is very well recorded, with minimum amount of processing and good spatial cues, as that seems to highlight the effect of the cross-talk reducing filters the best.

 

The filters worked in my system after a few false starts. The final version of XTALK reducing filters I settled on produced a more natural sound for voices, acoustic, and other well-recorded, minimally miked music. The result was a wider sound stage, and better focused, cleaner instruments and better sense of space. The sound extended further out and away from the speakers than with my regular filters. In fact I almost never heard the sound coming directly from my speakers with these filters.

 

The effect was obvious but not overwhelming, I’d say about 15% improvement compared to what I’m used to with my system in the above areas. By way of comparison, I find that USB cables produce no difference in my system, a better DAC might produce a 10-20% improvement, digital and analog interconnects mostly have no effect. So, a 15% improvement is actually significant in relation to other things I could try to improve

 

Large scale, well-recorded choral performances did benefit quite a bit from these filters: individual voices became easier to distinguish and locate in a large group, where previously they sounded more like a large jumble of voices.

 

Sounds of a large orchestra or synthesized or heavily produced rock recordings did not seem to benefit as much, but the filters never made things worse.

 

The non-cross-talk reducing version of the filters turned out to be very similar to the filters I constructed myself, so there wasn’t much reason for me to use these. They might still be very helpful for those who don’t know how to create your own filters by measuring the room response and optimizing phase.

 

Test System

Windows 10 PC with HQPlayer performing convolution, upsampling everything to DSD512, feeding Singxer SU-1 DDC connected to Gustard X20 Pro using I2S connection.

 

I used REW and a Behringer calibrated mic to create the initial measurements required by Thierry’s service.

 

Testing

Testing and evaluation was done by creating separate filter configurations in HQPlayer, one using my own filters, one using the XTALK-reducing filters, and one without the XTALK reduction. I carefully matched levels between all configurations to ensure a fair comparison.

 

I did a sighted evaluation for a while, recording notes on each filter set and the effect I thought I heard. I evaluated a large sample of music, from vocal to rock, jazz, and classical, orchestral and chamber, and various live recordings.

 

I then did a random blind evaluation. Between my original filters and XTALK-reducing filters, I could correctly identify which filter was playing about 90% of the time (3 sets of 10 trials each). For each of the 3 sets I focused on a specific characteristic of the filter I found significant, using a very short piece of music that I thought illustrated that difference the best (wider, more natural sound stage, more focused singer’s voice, better voice separation in a choir). I’m satisfied that the differences I found were not imagined.

 

Overall, I’m happy with Thierry’s cross-talk reducing filters, they’ll stay in my system, replacing my own. I recommend you try them yourself, but of course, YMMV!

[pkane2001]

13 hours ago, OldBigEars said:

I quit.  No can do.

 

An entire weekend of mind-numbing exploration, trying to make sense of this HAF product / service.  Hats off to those of you that managed to figure it out.  I suspect HAF is intended for geeks and engineers and works brilliantly for you guys out there.  

 

For music buffs and other hifi enthusiasts, simply trying to improve our room acoustics - HAF is not ready for prime time.  This stuff's gotta work, and Thierry's approach to sorting out customer installations by means of endless cryptic emails is touchingly personal, but inadequate and hugely frustrating for both him and his customers.  Here's an example of his email instructions:

 

 press "Start measuring" : REW will wait for a sync signal that is embedded in the attached sweep signal. As REW will play as well its own test signal when you press "Start measuring" (it doesn't do this), you must find a way to make sure this test signal will not be audible : the easiest way is to choose the internal card of your computer as output device (Preferences menu) and put your computer volume at zero

 

- play the left channel sweep signal (_L_refL) from your player and check that the level measured by REW is in the acceptable range (make sure the player stop after the file reading to not disturb the measurement) (when you play the sweep file from your player, REW doesn't record it)

 

It all sounds easy, except it doesn't actually work like he seems to be describing.  I got everything set up with the UMIK-1 and pressed "start measuring" as instructed.  REW simply plays it's own test file.  I've no clue how you're supposed to play the special Left and Right test files that Thierry sends out.  Since this email, I've received 5 emails from Thierry and the poor chap's received about 10 from me.  He seems to ignore the question every time

 

Apologies to all of you for letting off steam via this post.  My head's about to explode. UMIK-1 goes back to Amazon next weekend and we move on.  

 

Thierry - just make a how-to video. You'll thank me one day.

 

 

 

You seem to be missing the need for another software player (for example, HQPlayer) to play the custom test signal instead of REW.

 

REW built-in test signal must be sent to any output where it will not be heard (for example, your PC speakers with volume set to 0). This is selected through REW configuration screen.

 

HQPlayer or another software of your choice can play the test signal over your speakers, while REW input, connected to UMIK-1, will measure the result. You'll need to select 'Use Acoustic timing reference' in REW measurement screen, so it will wait to start measuring until it detects the signal from the microphone.

• Playback of the test file -> through any decent software player with output to your speakers
• REW output -> to any muted or disconnected speaker system, doesn't really matter which as long as you can't hear it
• REW input <- UMIK-1

Start REW measurement, first. It'll sit and wait for the timing signal. Then, start playback of the test file using your audio player. REW should detect the short chirp at the beginning of the file and start measuring the sweep that follows. It'll stop automatically.