Article: Audiolense Digital Loudspeaker and Room Correction Software Walkthrough

[cjf]

20 minutes ago, dallasjustice said:

I just returned my LT-Dante card. Dante/Audinate is truly a joke. I’d stick with USB. 

 

I have four channel setup; stereo setup with a pair of cascaded mono subs. I document the setup in the link below. It’s the best step response I’ve ever been able to achieve; never heard before bass!

https://www.audiosciencereview.com/forum/index.php?threads/cascaded-multi-driver-subwoofers.1341/

OK good to know about Dante..Ill do as you suggest and stick with USB

 

I think I may have answered my own question about Amp/Sub connections.. I guess there is nothing stopping me from still using my Analog PRE amp after the Lynx by running it in "direct/vol bypass" mode, assuming it has that.

 

Thanks the link, Ill give it a read

[dallasjustice]

12 minutes ago, cjf said:

OK good to know about Dante..Ill do as you suggest and stick with USB

 

I think I may have answered my own question about Amp/Sub connections.. I guess there is nothing stopping me from still using my Analog PRE amp after the Lynx by running it in "direct/vol bypass" mode, assuming it has that.

 

Thanks the link, Ill give it a read

I prefer digital volume control. I could never find a decent multi channel pre amp and I’m happy with digital volume control. Do you have a multi channel analog preamp?

[cjf]

1 hour ago, dallasjustice said:

I prefer digital volume control. I could never find a decent multi channel pre amp and I’m happy with digital volume control. Do you have a multi channel analog preamp?

My current Analog Pre has 2 pair of XLR Outs and a separate Sub out, all active if need be (Classe CP800). I was considering acquiring my unicorn Pre soon which is the Pass XP30 that also has two pair of XLR Outs but no sub out. That is, until I got sidetracked with the thoughts of Subs and DSP

Of course I would like to be able to have the Pass, DSP & Subs if I can. I'm liking the thoughts of the Lynx though for sure. Sounds like a very big bang for the buck that may be the ticket to having all these options. I'll kick my Meitner to curb for that capability.

 

Software volume has been a concern for me but maybe only in theory. I wondered what happens when the PC crashes or the Volume control service craps out mid playback. Will the outcome be unity gain to amps and speakers while the volume control App/Service recovers?

[mitchco]

@cjf it looks like @dallasjustice answered most if not all of your questions (thanks Michael!). I have been running with software/digital volume since 2011 using JRiver and have not had any incidents. Make sure Windows Sounds in Playback devices, Sound tab, are turned off, as well as Play Windows Startup sound is disabled. With the PC running, I can reboot the computer without any sound issues. If using JRiver, always good to have volume protection enabled...

 

Michael's time aligned results from using the cascaded subs method and Audiolense are excellent. My results are similar using stereo subs, to be seen in a follow up article in the New Year.  Cheers, Mitch

[cjf]

Hello @mitchco Thanks for the added details.

 

I'm curious what the typical REW hardware setup would look like in order to log accurate enough room measurements that you feel your not cutting your expensive equipment short of its capabilities by basing the final Audiolense FIR filters configuration on numbers gathered via a less then ideal MIC/MIC Pre. Basically a "garbage in / garbage out" scenario. Not saying thats the case here but I can see it being a possible issue if caution is not used.

 

I've been monkey'ing around with an XTZ Room Analyzer setup for measurements with Dayton MIC but cant say I'm all that impressed with it. The RCA Line Level outputs lack any real "gain" to sufficiently feed my Analog Preamp's Inputs. I basically need bury the volume of the Preamp to get anywhere near what my normal listening levels are and even then its not really ideal.

 

Thanks

[mitchco]

@cjf I use an older microphone kit from http://www.isemcon.net/ashop/index.php?cPath=2_23_28 that is no longer available. It was a combo calibrated mic and preamp kit and still works well and relatively inexpensive.

 

There is a shootout of measurement mics here: http://www.blouder.com/affordable-measuring-microphones-shootout-part-3/  Also one from Ethan: http://realtraps.com/art_microphones.htm  As you can see, most of the measurements mics are similar in performance. Some folks will only use http://earthworksaudio.com/measurement/ using a high quality mic preamp http://earthworksaudio.com/products/preamps/zdt-1021/  

 

Not sure what the gain issue is, but my kit uses a mic preamp and RCA line level outputs with plenty of gain back to the Hilo ADC... 

 

In my experience, the most important aspect is that the mic is calibrated and comes with a calibration file. We are talking about fine tuning the perceived frequency response (i.e. tonal balance) arriving at ones ears. We can discern a 1 dB difference in frequency response, so accuracy and precision counts.

 

Happy New Year!

[vitalii427]

Mitch, thanks for a great article! Waiting for the next one.

Which subs do you have?

[number8]

On 30/12/2017 at 1:19 AM, dallasjustice said:

I just returned my LT-Dante card. Dante/Audinate is truly a joke. I’d stick with USB

 

 

I would be interested if you could elaborate on that. Is it a matter of price or SQ?

thanks

[dallasjustice]

6 minutes ago, number8 said:

 

 

I would be interested if you could elaborate on that. Is it a matter of price or SQ?

thanks

The LT-Dante does not auto switch sample rate. IOW, the user must manually change the sample rate before switching to a new sample rate. I also couldn’t connect Dante ASIO  to Jriver ASIO line in while also connected to Jriver ASIO output. So maybe it’s not really multi-client or maybe the ASIO isn’t really Steinberg compliant. 

 

IME, the best USB implementations are far superior to the best AES67 in terms of flexibility. 

 

They sound the same. 

[number8]

44 minutes ago, dallasjustice said:

The LT-Dante does not auto switch sample rate. IOW, the user must manually change the sample rate before switching to a new sample rate. I also couldn’t connect Dante ASIO  to Jriver ASIO line in while also connected to Jriver ASIO output. So maybe it’s not really multi-client or maybe the ASIO isn’t really Steinberg compliant. 

 

IME, the best USB implementations are far superior to the best AES67 in terms of flexibility. 

 

They sound the same. 

Thanks I really appreciate your input. The benefit I see in the ETH interface, is to be able put all computer stuff outside the listening room.

[mitchco]

On 03/01/2018 at 9:30 AM, vitalii427 said:

Mitch, thanks for a great article! Waiting for the next one.

Which subs do you have?

Hi @vitalii427 Thanks. Subs will be disclosed in the next article...

[cjf]

On 12/31/2017 at 2:27 PM, mitchco said:

@cjf I use an older microphone kit from http://www.isemcon.net/ashop/index.php?cPath=2_23_28 that is no longer available. It was a combo calibrated mic and preamp kit and still works well and relatively inexpensive.

 

There is a shootout of measurement mics here: http://www.blouder.com/affordable-measuring-microphones-shootout-part-3/  Also one from Ethan: http://realtraps.com/art_microphones.htm  As you can see, most of the measurements mics are similar in performance. Some folks will only use http://earthworksaudio.com/measurement/ using a high quality mic preamp http://earthworksaudio.com/products/preamps/zdt-1021/  

 

Not sure what the gain issue is, but my kit uses a mic preamp and RCA line level outputs with plenty of gain back to the Hilo ADC... 

 

In my experience, the most important aspect is that the mic is calibrated and comes with a calibration file. We are talking about fine tuning the perceived frequency response (i.e. tonal balance) arriving at ones ears. We can discern a 1 dB difference in frequency response, so accuracy and precision counts.

 

Happy New Year!

Thanks for the additional details and recommendations @mitchco @dallasjustice

 

I've got a Lynx Hilo, Earthworks ZDT MIC Pre and Earthworks M30 Inbound. Time to get serious with this Audiolense DSP stuff

[R1200CL]

On 30.12.2017 at 12:46 AM, dallasjustice said:

WRT Roon’s convolver and Audiolense filters, my experience is that Roon’s convolver does not work properly. I started a thread on Roon forum about the problems. Roon hasn’t fixed the issue I’ve experienced but acknowledged they’ve reproduced it using my Audiolense filters. Of course, I’m super disappointed Roon’s convolver does work right. But I am hopeful they will fix it. 

 

I’m trying to find that thread. Link please ?

[R1200CL]

@mitchco

I’m in a process of understanding what the different room correction SW does or doesn’t. Which I think is almost a science of it’s own ?

 

Except from UI, good guides, support etc. 

Are there any main difference between Audiolense and Acourate ?

Can they in principle do (exactly) the same ?

 

 

 

 

 

 

[dallasjustice]

8 hours ago, R1200CL said:

 

I’m trying to find that thread. Link please ?

 

https://community.roonlabs.com/t/audiolense-convolution-filters-in-roon/35603

 

Roon acknowledged the issue but I haven’t heard anything from them in weeks. I don’t think it’s fixed. I’d try Roon convolver is you already have it. Maybe it will work. But for the routing setup I use, Roon’s convolver is broken. 

 

You coukd also use HQplayer’s convolver with Roon. I know HQP convolver works. I prefer to use Jriver tho. 

[mitchco]

13 hours ago, R1200CL said:

@mitchco

I’m in a process of understanding what the different room correction SW does or doesn’t. Which I think is almost a science of it’s own ?

 

Except from UI, good guides, support etc. 

Are there any main difference between Audiolense and Acourate ?

Can they in principle do (exactly) the same ?

 

 

 

 

 

 

@R1200CL I think @dallasjustice comments earlier cover some of this.

 

For sure, designing custom FIR filters for one's speakers in a room is a huge subject area. My eBook is one of many on designing DSP FIR filters, along with a number of articles here on CA. In principle, they can produce similar results, but there are nuances, like different psychoacoustic filtering, for example.

 

Both are excellent products  with state of the art DSP functionality, that can work with virtually any loudspeaker and room configuration. Loudspeakers in rooms can be fully optimised both in the frequency and time domain to your ears.

[R1200CL]

11 minutes ago, mitchco said:

My eBook is one of many on designing DSP FIR filters

 

I probably buy that book. But I understand it’s quit linked with Acurate. I don’t know if Audiolense need a step by step guide. But If so, any plans of incorporating Audiolense in that book ? Or a new book. 

 

If needed at all. It seems to me that maybe Audiolense is perhaps a bit more user friendly. 

 

[mitchco]

3 hours ago, R1200CL said:

 

I probably buy that book. But I understand it’s quit linked with Acurate. I don’t know if Audiolense need a step by step guide. But If so, any plans of incorporating Audiolense in that book ? Or a new book. 

 

If needed at all. It seems to me that maybe Audiolense is perhaps a bit more user friendly. 

 

I appreciate your support. While the eBook walks through using Acourate, the DSP principles applied are the same. There are several sections in the eBook that are not tool specific and apply to understanding why we hear what we hear in small room acoustics, acoustic measurement techniques, understanding some parameters of good loudspeaker design (e.g. controlled directivity) and understanding industry guidelines and standards for achieving accurate sound reproduction in critical listening environments.

 

If you click on the Amazon link to my eBook and click on Look Inside, you can peruse the table of contents and read the first few chapters for free. I have plans to update the book on several aspects (e.g. sub integration plus some topics here) and cover more DSP tools, including Audiolense. I don't have an ETA for that yet and is a ways out.

[nefilim]

thank you for the incredible write up ! i’m curious how your components are physically connected to your Hilo and how you plan to add the subwoofers in, doesn’t look like the Hilo has that many lines out or am I missing something ?

[mitchco]

Glad you enjoyed the article. The Hilo has 6 analog outputs or 3 sets of stereo outputs. The line out L/R go to the midwoofers, the monitor out L/R are going to the tweeters and headphone out L/R are going to subs. Both the monitor and headphone out have analog volume control to match the different sensitivity levels of the drivers if required. Scroll down to the analog performance section to see  the tech specs. I have had no issues and sounds great.

 

I have a pair of subs hooked up for the past 3 months and about 3/4 the way through the next article on integrating and time aligning subs to mains. Should be out soon.

[nefilim]

interesting thanks @mitchco do you know if you could use a digital out concurrently with the analogue outputs? I'm interested in the hilo, to use its internal DAC for line out to my subs and use digital output to my existing DAC to drive my mains.

time alignment could be interesting ?

ps. working my way through your eBook,

really great and looking forward to the second version!

[mitchco]

Yes I think so, but I have not tried it myself. I believe @dallasjustice is using the Hilo this way and could confirm.

Thanks for purchasing my eBook. Feel free to PM me with any questions.

[dallasjustice]

6 hours ago, nefilim said:

interesting thanks @mitchco do you know if you could use a digital out concurrently with the analogue outputs? I'm interested in the hilo, to use its internal DAC for line out to my subs and use digital output to my existing DAC to drive my mains.

time alignment could be interesting ?

ps. working my way through your eBook,

really great and looking forward to the second version!

I need 8 channels in my setup. So I use 6 Hilo analog out plus Hilo AES to Benchmark DAC3. It’s works perfectly. There’s no problem with synchronization.

 

I tried other DACs like the MOLA MOLA and it didn’t work.  The MOLA has a goofy jitter attenuation scheme that results in variable propagation delay. As long as you pick a well engineered AES/spdif DAC which exhibits consistent propagation delay, you are good to use an external DAC with the Hilo for digital crossovers. 

[nefilim]

Not finding a lot of documentation on Audiolense' site, I'm wondering if anyone know what this means: 

 

"Clock drift correction in measurement is now practically perfect."

 

Does this imply I can measure on a different device than the playback chain? eg one USB device for ADC and another USB device for a DAC?

[nefilim]

23 hours ago, dallasjustice said:

I need 8 channels in my setup. So I use 6 Hilo analog out plus Hilo AES to Benchmark DAC3. It’s works perfectly. There’s no problem with synchronization.

 

I tried other DACs like the MOLA MOLA and it didn’t work.  The MOLA has a goofy jitter attenuation scheme that results in variable propagation delay. As long as you pick a well engineered AES/spdif DAC which exhibits consistent propagation delay, you are good to use an external DAC with the Hilo for digital crossovers. 

 

Thanks Dallas, curious, which channels are you connecting to the Benchmark ?