Roon & Home Audio Fidelity (Room Correction / convolution filter creation)

(Larry Post) #246

My x-talk filter is about 3db lower than my non x-talk, anyone else notice this?


Yes, makes comparison a little harder. Incidentally, the other way to easily switch between filters is to create a DSP preset for each - don’t think it’s any quicker but maybe slightly less confusing.

(Rémi) #248

It’s quicker in my case to create presets, as the “headroom management” parameter is different from one filter to the other, as mentionned by Larry_Post. In order to precisely know the relative headroom adjstment between two filters, I use REW : import impulse response Left / channel 1 for each filter, and measure the gap. This can also be done by ear but I find it difficult to hear differences below +/- 1dB.


Ah, that’s a handy tip, thanks - I was just doing it by reference to the clipping indicator before.


You can also change the gain of each FIR filter such that all filters have the same gain e.g. for a specific frequency. I chose 440 Hz concert pitch tone played it with all the filters received from Thierry and measured with a dB meter at a set volume that represents my normal volume. Then I adjusted all the filter gains that they have the same amplitude (in dB) when playing the concert pitch tone (440 Hz sine tone).

(Larry Megugorac) #251

Holy smokes Streamy…Is it only me or now i’m way confused (easily done BTW) with all you’ve said…:confounded:

I’m still only listening to one of his filter sets so I can ascertain the difference with my previous Mini DSP Hardware…I guess I need to look into Pre sets so I can change between different sets…What Streamy describes is way over my head it seems…

That DSP Pre-sets option works great for changing filter sets! Thanks for that Tip dhusky! Also able to figure out how to compare using the other suggestions above…still digesting streamy68 though…

(Larry Post) #252

Are you using the Headroom Adjustment or Speaker Setup or something else like resample each wav file to apply the level adjustment?

(Rémi) #253

This works but be careful : two sets of filters can have the same gain at 440Hz but different average gain over 20-20000Hz. I recommend calibrating filters with a white noise instead. REW can do it with the SPLmeter and Generator modules. White noise is preferable to pink noise in this case to be more robust to the high variations of the filters in the lower part of the spectrum (but in general calibrating with white noise or pink noise should give the same results, just try…).


I agree with your advise but decided against it because I did not want to have differences in gains that are due to the room modes in the bass range and are the main reason why using room correction filters would influence the set filter gain. Else I would have normalized the filters by summing up the filter coefficients, which would be the right way to determine the filter gain. Maybe my rational is wrong, but listening to the different filters by swiching them on and off in Roon gives me the impression that the gains are the same after the correction I did.


I’m a bit confused.
@Magnus if I understand him correctly says, use pink noise file and measure by using Make Measurement
I downloaded some pink noise and tried. His guide did not mention what settings to use

But these sweep files sound not like pink noise, so now I’m confused what actually to do.

Shall I use pink noise or sweep files in Roon ?

I think Magus’ guide only focus on that you actually have the PC connected to your pre, which I havn’t.
Have I got it right then ? And I should use Alec way of doing this ?

I was using balance on my pre, but I guess using those files will do.


More confusing:
I start with playing left, and Roon right away jumps to play right. I think I will figure out how to only play that file.

My setting is like this:

So I use default output and Both and Left.

My first result looks like this:

Does it seems right ?
If so, when I then play the Right sweep file, should then Output be set to Both and Right ?

I’m only getting 5,5 seconds, and not 5,9 seconds as shown in Alec guide. Should I change and how to do ?

The sound sound very laud compared to the pink noise file. Is that a problem ?

Also it seems REV says 16 bit down left corner, but the Sweep file is 24 bit. ??

And finally. I’m running this through HQPlayer. Does it matter ?

(Magnus) #257

Don’t confuse my guide with Home Audio Fidelity discussed in this thread, I use a simplified room correction without any phase modifications, using REW which is free, and in my guide I suggest using “Pink PN” and moving mic to get a good average of frequency response.

The HAF filters Thierry does is more advanced, and he need Sweep measurements since those measurements contains phase information .

For optimal sound quality, use HAF, it gives higher sound quality than what you can get straight out of REW or from my guide. But if you want to test and play around with room correction, feel free to try my guide. That way, you also get something to compare with the HAF filters.


Well my goal is to use

But I’m struggle to understand how to do the measurements correctly from Roon.

So that’s why I’m asking all these silly questions as I’m not able to understand how to do the most basic things.

I only intend to use REV for measurements.

(Magnus) #259

I did a quick guide for that in this thread, September 17 2017.

(Chris) #260

You do the measurements with REW or something similar with a laptop or computer’s audio outputs connected to your stereo. Once you get the final filters, then you plug them into Roon. You don’t use Roon for the measurements


I need answer to my specific questions.
Of cause I use Roon to play pink noise and sweep files. To me there is no other way.

And actually I think Roon should have a generator built in for these files.

Not sure why I need pink noise though.

(Chris) #262

Well you’re gonna have some problems doing this if you expect Roon to do this.

Help us help you – why can’t you connect a computer to your preamp to run the sweeps from REW or similar software?

(BTW, I don’t ride motorcycles anymore, but when I did, I always rode BMWs!)


I’m doing as this guy says here:

And here:

As said, @alec_eiffel settings in REV seems to be a bit different than mine, so hence these questions I’m asking specific about the settings here:

So I did step 1 to 4 in Magnus guide. Not knowing what purpose they have. I did this by downloading a pink noise file from here:


Let’s take a step back.

@R1200CL - do you have a DAC with a USB input? The way this worked for me, is REW runs on my laptop, which has a USB input for the Mic capturing the sound and the laptop is also plugged into my DAC from the laptop’s USB to my DAC’s USB. From the laptop, REW produces and measures the sounds, be they frequency sweeps or pink noise (though I only used the latter to check levels). Roon is not involved in this process.


Hi R1200CL,

So, I also followed that guide. Step 1 of Roon & Home Audio Fidelity (Room Correction / convolution filter creation) points you to the sweep files you need which, as you say, you can play through Roon just fine. Like you, my total time was also different to the screenshot, I think the same value as yours, but this worked fine. As for the output, I can’t quite remember how this was set, but I think I may have turned it off to avoid my own confusion as the sound was coming from Roon. I should say I’m no expert here and don’t properly understand all the settings but I managed to generate what Thierry needed for the filters. Don’t forget you can always email him as well if you get stuck.

To my mind it makes sense to play via Roon rather than direct, as that’s the same path your audio will take afterwards - I realise not everyone agrees with this though.