A Different Way To Apply Digital Room & Loudspeaker Correction

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nicoff

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A number of digital preamps sold today have digital room correction capability. They have built-in software to allow users to create digital room correction filters.


However, the large majority of digital preamps (including the Bryston SP3 that I use) lack that feature. Since I am also using Roon and Roon can work with room correction filters, I decided to investigate.


Doing some reading I learned that there are very powerful software packages that can develop these filters (Acourate, Dirac, and others.). These packages are not cheap; they are meant for commercial use and do require a steep learning curve.


I then read about of a service being offered by a French company called Home Audio Fidelity (HAF). They offer to create the room correction filters for you. You still have to do some homework though. You have to use a calibrated microphone and (free software) to measure the audio response for your room and loudspeakers (HAF explains how to do that and guides you through the process). Then you send them the audio response files and HAF will create the filters for you. You then apply those filters in Roon and now you have room correction in your current system.


I just went through that process. HAF provided me with room correction filters for both Roon and HQPlayer. I have applied the room correction filters to both and I am very happy with the results.


Going the HAF route is cheaper than purchasing sophisticated audio software; it saved me from having to dedicate time to learn new software; it is (much) cheaper than buying acoustical treatments for my fairly large room; and I benefitted from having an expert guide me and develop the filters for my room. Overall, I am very pleased that I went that route. Highly recommended.
 
Nice... so the one question I have is about how much of a price tag total to add something like this to my system? I assume it works with HQPlayer.
 
A Different Way To Apply Digital Room & Loudspeaker Correction

They have different packages. The one that I bought includes two types of filters: the mod-filters and the cross-talk filters. I paid $159 euros (about US$190 based on current exchange rate plus Paypal fees). A less expensive package only include the mod-filters. They also have other packages that include filters for headphones.

HAF lets you try it out before you commit to purchase. After you have done your room measurements you send the file to them together with a couple of your own music tracks. They apply the filters to your tracks and they send you back your modified tracks. Then you can listen and decide if you like what you hear or not. You have nothing to lose except your time.

And yes it works perfectly with HQPlayer. HAF will provide you the filters for HQP as well and directions on how to install them.
 
I do it in jriver Media center. The process I went through was using REW and a calibrated mic to measure from my listening position. I took a look at the areas that needed correction and installed a increase or decrease at the center point of the problem for a specified bandwidth using the parametric equalizer function. My JL audio fathom sup also has build in DSP with its own mic.
 
Mike B. said:
I do it in jriver Media center. The process I went through was using REW and a calibrated mic to measure from my listening position. I took a look at the areas that needed correction and installed a increase or decrease at the center point of the problem for a specified bandwidth using the parametric equalizer function. My JL audio fathom sup also has build in DSP with its own mic.
Click to expand...

I do not think that what JRiver does is the same as the type of correction filters that I am talking about. I do know that other software like Acourate and Dirac can create the correction filters, but one must first learn to use the software.
 
Mike B. said:
I took a look at the areas that needed correction and installed a increase or decrease at the center point of the problem for a specified bandwidth using the parametric equalizer function.
Click to expand...
Be careful with that. Cutting peaks is fine, but boosting nulls is not. You are using a pressure microphone. It is telling you pressure, but not the particle velocities, so it is only giving partial info of that soundfield sample. There is indeed a pressure null/energy storage at that point. But move the mic slightly and it will be different. When you boost that pressure point to fill in the null and make it flatter at that point/spatial position , you have made peaks at other points/spatial positions. This is not necessarily a good thing. So cutting peaks is ok, but be very judicious with boosts.
We hear a combination of the direct and indirect sound at the listening position. Making the direct better, but the indirect worse, will change the perceived timbre. If you like it, fine, but beware.
 
nicoff said:
I do not think that what JRiver does is the same as the type of correction filters that I am talking about. I do know that other software like Acourate and Dirac can create the correction filters, but one must first learn to use the software.
Click to expand...

Lets see your before and after room scans. That will show how well they did.
 
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3b88bf9b2a6084633cfe03ceba931e83.jpg
 
That is impressive. What program did you use to record them? I have not seen that format before.
 
nicoff said:
b746f025239fa4a8b78b3dfc5dfef114.jpg


3b88bf9b2a6084633cfe03ceba931e83.jpg
Click to expand...

Hi Nicoff,

Where is the microphone position during the top unsmoothed graphs? The unsmoothed ones are bass frequencies only it seems, the smoothed full bandwidth. The smoothed versions appear to be mid/far field, i.e listening area?
The Orig smoothed scale is 10db divisions. The Mod version is 20db, "squishing" the graph vertically and making an apples to apples before/after comparison more difficult and the "Mod" version a bit flatter. Very naughty.:)
I am a bit alarmed by much of what I see, but if it sounds better to you....
 
A Different Way To Apply Digital Room & Loudspeaker Correction

AJ Soundfield said:
Hi Nicoff,

Where is the microphone position during the top unsmoothed graphs? The unsmoothed ones are bass frequencies only it seems, the smoothed full bandwidth. The smoothed versions appear to be mid/far field, i.e listening area?
The Orig smoothed scale is 10db divisions. The Mod version is 20db, "squishing" the graph vertically and making an apples to apples before/after comparison more difficult and the "Mod" version a bit flatter. Very naughty.:)
I am a bit alarmed by much of what I see, but if it sounds better to you....
Click to expand...

I have actually requested some tweaking to the lower frequencies so after that is done I will ask for a graph of the comparison using similar scales.

AJ, feel free to share what you see!

The nice thing here is that the folks at HAF work with you and let you change things until you are satisfied.

As far as microphone location, it was placed at 9 total locations. The first location is the sweet spot and then 8 random locations around the sweet spot. 9 measurements for each L-R channel (18 measurements total).
 
A Different Way To Apply Digital Room & Loudspeaker Correction

I now have my tweaked files back and have to say that the sound of the system using the new convolution filters is fantastic.

The soundstage is wider and fuller. There are no holes/voids in the wall of sound being presented. Instruments that were previously hidden behind other sounds are now present. This tweak costs less than $200. That is much less than what many folks spend on fancy cables. Yet the change in the sound is not subtle.

I highly and wholeheartedly recommended this approach to anyone using Roon or HQPlayer.
 
Re: A Different Way To Apply Digital Room & Loudspeaker Correction

nicoff said:
I now have my tweaked files back and have to say that the sound of the system using the new convolution filters is fantastic.

The soundstage is wider and fuller. There are no holes/voids in the wall of sound being presented. Instruments that were previously hidden behind other sounds are now present. This tweak costs less than $200. That is much less than what many folks spend on fancy cables. Yet the change in the sound is not subtle.

I highly and wholeheartedly recommended this approach to anyone using Roon or HQPlayer.
Click to expand...

Interesting!

My only observation is that be sure you do not use the digital correction as a band-aid for issues that could have been addressed otherwise.

You probably have already done this, but I urge my readers & clients to get the system as best they can organically - best Dynamics, Presence, & Tone (working with the room, without any sort of room correction), and only then introduce the digital room correction as necessary.
 
A Different Way To Apply Digital Room & Loudspeaker Correction

Jim Smith said:
Interesting!

My only observation is that be sure you do not use the digital correction as a band-aid for issues that could have been addressed otherwise.

You probably have already done this, but I urge my readers & clients to get the system as best they can organically - best Dynamics, Presence, & Tone (working with the room, without any sort of room correction), and only then introduce the digital room correction as necessary.
Click to expand...

Totally agree!
I spent weeks to find the best location for the speakers based on room dimensions and use restrictions (room serves as theater as well). Also added diffusers (plants).
System has never sounded better! Well worth it!
 
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