Recording Impulse Responses for Speaker Virtualization

[gregorio]

guys i've experienced a weird thing: i normally use my best hrir with the new topping a90d that's supposed to be a very good amp, yesterday i tried the same hrir with my "old" jds atom+ and i experienced a whole new level of spaciality that's missing with my a90d, why this is happening?

There are a number of reasons it could be happening. It’s common that we change something like an amp or DAC, experience some difference in the musical details, colouration and/or spatiality and then falsely put this down to that one variable of changing say the amp by ignoring all the other variables that have changed. For example, differences in the volume level between the amps, small differences in positioning/repositioning the HPs/IEMs or just differences in our perception, how we’re listening, what we’re focusing on and how our cognitive biases are affecting our perception.

could a "colorful" amp influence in a negative way to the overall quality of the listening experience with the recorded hrir?

Yes but it would need to be a truly “colourful” amp and there are very few of those, one or two of the tube amps which add exceptionally high levels of distortion. I’m not sure there are any HP amps with such high levels of distortion and the two you mention certainly don’t, unless you have some esoteric HPs which require you to overdrive one of the amps?

G

 

[minghuisong]

Is room correction necessary for an anechoic chamber?

 

[jaakkopasanen]

Is room correction necessary for an anechoic chamber?

I'd say yes since anechoic chamber will sound drastically different than a regular listening room for which the content is produced for.

 

[reter]

i would pay to record my hrir on an anechoic chamber

 

[minghuisong]

Headphone compensation compensates both mic and earphone frequency response, so is the main purpose of room correction to correct the speaker? I wonder what room correction does

 

[castleofargh]

i would pay to record my hrir on an anechoic chamber

Get yourself several power extension cords and a field with a house nearby. Bribe the owner anyway you can, so he'll give you power and time on his field to act like a total lunatic.
Set up your speakers off the ground.
Profit.

It's not anechoic, but it sure gives way lower reverb than walls and roof.

 

[Steve999]

Also with room correction you are trying to knock down major peaks in the low and mid bass region due to room modes, which are attributable largely to the geometry of the room and how that can exaggerate response at certain frequencies. I use two subwoofers to smooth out the modes some and then EQ things in the low and mid bass to smooth things out some more. If you already have nice speakers then cleaning up these room modes can be low hanging fruit in terms of experiencing the pleasure of smooth and extended mid and low bass. For example I learned to use a software called REW with calibration microphone called a umik-1 to identify and smooth out my room modes. It’s a really enjoyable improvement.

FWIW, IMHO & etc.

 

[gregorio]

Is room correction necessary for an anechoic chamber?

An anechoic chamber does not need room correction because by definition there is no room acoustics to correct for.

Maybe you mean something else though, for example; would we need to compensate for the fact that an anechoic chamber has no acoustics (when listening to music recordings created for playback in a room with acoustics)?

G

 

[musicreo]

Is room correction necessary for an anechoic chamber?

There are no reflections from the walls in an anechoic chamber. I think you would correct only the speaker response instead of the speaker with the room.
Probably you would like to add some reverb to make the sound more enjoyable.

There have been no experience reports for a while now? Is the measurement and post processing process to obtain good results to difficult and nobody has done any measurements in the last months?

 

[morgin]

Is the measurement and post processing process to obtain good results to difficult and nobody has done any measurements in the last months?

Im very happy with mine. But there’s no way of me knowing if it can be improved and by how much unless I do many many measurements and go back and forth. When does it stop? Maybe I’ll try again in the future but so far the latest is the best for me.

 

[mterm1]

There have been no experience reports for a while now? Is the measurement and post processing process to obtain good results to difficult and nobody has done any measurements in the last months?

I would say my results are 'ok' - I have had times where it is possible to get confused whether the audio is coming out of the headphones or speakers, but in general I much prefer speakers. I have tried multiple types of capsules, have tried silicon as well as foam plugs, have captured multiple speakers at home as well as two high-end audio systems in acoustically treated environments, but unfortunately none are comparable in quality to listening to speakers.

 

[musicreo]

Im very happy with mine. But there’s no way of me knowing if it can be improved and by how much unless I do many many measurements and go back and forth. When does it stop? Maybe I’ll try again in the future but so far the latest is the best for me.

I also still use my more than two years old measurement and only did some minor changes in equalizing in the last year. I tried to optimize the measurement but I reached with that old measurement a limit in quality that is hard to top. If there is a major improvement in the microphones I will do measurements again but until then I'm very happy

I would say my results are 'ok' - I have had times where it is possible to get confused whether the audio is coming out of the headphones or speakers, but in general I much prefer speakers. I have tried multiple types of capsules, have tried silicon as well as foam plugs, have captured multiple speakers at home as well as two high-end audio systems in acoustically treated environments, but unfortunately none are comparable in quality to listening to speakers.

Did the high-end audio systems in acoustically treated environments improve your results? In the moment I think that the quality of the microphones, their mounting and their proper in ear placement are much more important than having the perfect room to measure. Also I think that post processing is important to get the best results.
For example I do a lot of equalizing. The screenshot shows the many filters (calculated) I use with my measurement and on top of that I use a low pass , peaking and high shelf filter in EQ-APO set up by carefully listening and comparing the headphone with the speaker sound.

 

[minghuisong]

How do you calculate the speaker channel delay?

 

[jaakkopasanen]

How do you calculate the speaker channel delay?

Location of the first positive or negative peak of at least -12 dB in the impulse response.

 

[Spyartinc]

Did anybody get any success with Iem according to the manual? My issue is I can't get that soundstage as I get in over ear headphones. Also balances of instruments are pretty off as well. Experimented with different targets but cant get any closer to over ear (even closed ones)