What can do more than anything to improve your room & speakers? FIR filters maybe?

[Feanor]

What the heck is a FIR filter? For relatively simple explanation (of the kind I need), see THIS link.

Or you could ask Google AI as I did and got this answer ...

FIR (Finite Impulse Response) filters are digital tools used to achieve highly precise audio correction for both speakers and the rooms they are in. Unlike traditional IIR (Infinite Impulse Response) filters, FIR filters can manipulate frequency response and phase response independently.

Speaker Improvement

• Phase Correction: Speakers naturally introduce phase shifts, especially at crossover points where different drivers (like a woofer and tweeter) meet. FIR filters can "flatten" this phase, ensuring all frequencies arrive at your ear at the same time to prevent transient smearing.
• Linear-Phase Crossovers: They allow for steep crossover slopes that do not introduce the phase distortion common in analog or IIR designs, resulting in more natural sound reproduction.
• Driver Alignment: Manufacturers use FIR filters to match the magnitude and phase of different speaker models, making it easier to tune them together in complex setups.

Room Improvement

• Room Mode Mitigation: They are used in advanced Digital Room Correction (DRC) systems to address "room modes" (boomy bass or dead spots caused by room shape) with high precision.
• Boundary Correction: FIR filters can compensate for acoustic anomalies caused by a speaker’s proximity to walls or other boundaries.
• Complex EQ: Because they can create very detailed frequency curves, a single FIR filter can replace a complex chain of multiple parametric EQ filters to correct a room's specific acoustic profile.

So how do you construct a FIR filter? The freeware program, REW, is one one which is consider highly accurate and precise but has a steep learning curve. Recently I discovered a much simpler tool, also free, that will produce excellent FIR filters, at least in my limited experience: that is Gsonic. The is an excellent thread on Gsonic, started by the developer, at ASR.

The other question is how FIR filters to be applied. The the answer is that numerous computer players and stand-alone streamers are able to apply FIR filters.

I have used Gsonic to build FIRs and am currently using Equalizer APO to apply them on my Win 11 PC.

 

[Feanor]

Hello!!! Anybody? Anyone?

Is nobody using DSP room correction, (so called) in their main stereo systems? Surely a few are useing DIRAC or similar DSP in their home theatre systems, but what about the former?

Above I said that using an FIR convolution filter in my system was a very big improvement, probably the biggest overall improvement in my system in many years. Unless my ears are failing me terribly, I'm hearing imaging and soundstage improvements, and also big bass improvements (likely due to better subwoofer integration). BUT I'd like others to share their own experiences ... if any.

I suspect results will vary. Those with finely tuned listening room should probably find the least improvement. Also, those using full-range planars, (electrostatics), might fine less improvement because such speakers ought to have fewer phase, impulse, and time domain shortcomings than dynamic driver systems

 

[Bones13]

Back in my small room, I did make a convolution filter for Roon, using REW. This was after I figured out that I could not eliminate a 40hz boom with room treatment. It made some difference, not relevatory. It also did not affect vinyl playback.

There certainly a squad over at Audiophile Style who use room correction systems, big and small. As well as a gentleman who makes custom filters. So it is done.

I get the feeling that many here, including myself, (sub)consciously object to inserting both a ADC and the following DAC into the analog output stream. Many also use high end vinyl, and don’t want their pure analog subjected to this treatment.

I would find it hard to stomach having a high end DAC, and or Vinyl, being dependent on the unknown DAC chip at the end of the room correction device. I’m not saying that it would sound bad, and I will consider a Roon convolution filter again when my system changes are complete this fall. (LOL on “complete”) But in general, in my 2.0 main system, I have no plans to insert a room correction device between pre-amp and amp(s). In the TV room, I did use the microphone to set the 5.1 Sony AV receiver, with its built in correction software.

 

[Feanor]

Back in my small room, I did make a convolution filter for Roon, using REW. This was after I figured out that I could not eliminate a 40hz boom with room treatment. It made some difference, not relevatory. It also did not affect vinyl playback.

There certainly a squad over at Audiophile Style who use room correction systems, big and small. As well as a gentleman who makes custom filters. So it is done.

I get the feeling that many here, including myself, (sub)consciously object to inserting both a ADC and the following DAC into the analog output stream. Many also use high end vinyl, and don’t want their pure analog subjected to this treatment.

I would find it hard to stomach having a high end DAC, and or Vinyl, being dependent on the unknown DAC chip at the end of the room correction device. I’m not saying that it would sound bad, and I will consider a Roon convolution filter again when my system changes are complete this fall. (LOL on “complete”) But in general, in my 2.0 main system, I have no plans to insert a room correction device between pre-amp and amp(s). In the TV room, I did use the microphone to set the 5.1 Sony AV receiver, with its built in correction software.

I guess FiR convolution does have its limitation when it comes to extreme peaks & troughs; to be expected.

I can understand instinctive reservations about inserting ADC-DAC into an analog stream. I don't listen to LPs anymore but given quality converters, I doubt I'd worry about. Similarly a FIR-filtered stream to one's DAC isn't going to be "bit perfect" by definition. Nevertheless, the better the DAC the less to worry about.

 

[nicoff]

To the OP: If you follow the science, DSP and FIR filters can do far more to improve speaker/room interaction than cables, power conditioners, fiber, switches, streamers, DACs, or the latest gimmick. If you trust only your ears, then only you can decide what matters.

 

[Feanor]

Thank

To the OP: If you follow the science, DSP and FIR filters can do far more to improve speaker/room interaction than cables, power conditioners, fiber, switches, streamers, DACs, or the latest gimmick. If you trust only your ears, then only you can decide what matters.

Thank you, nicoff. Based ultimately on my ears, I agree with you, (your first sentence).

In case of FIR filters I listened to the science as best I understood it and my "ears" confirmed science's assertions. I reported my recent experience that using a FIR convolution filter was the biggest improvement to my system in years -- I'm sticking with that assertion.

I have 55 years experience as an audiophile. I spent decades listening to other audiophiles insist that "cables, power conditioners, fiber, switches" made a significant differences -- but my "ears" never definitively confirmed that they did. Differences that I thought I heard from time to time on account of these were extremely small. About 20 years ago I concluded that such differences were insignificant or entirely imaginary. Biases and wishful thinking are big factors in the "golden ear" experience.

My experience with an FIR convolution filter are another matter. In this case my "ears" confirm that by (at least partially) compensating for room and speaker issues, meaningful improvements are achieved.

 

[Michaels HiFi]

To the OP: If you follow the science, DSP and FIR filters can do far more to improve speaker/room interaction than cables, power conditioners, fiber, switches, streamers, DACs, or the latest gimmick. If you trust only your ears, then only you can decide what matters.

It wouldn't be the first time we've been told to "follow the science" only to then find out it was 100% wrong.

History has taught us to be very skeptical of when that phrase is used.

 

[Feanor]

It wouldn't be the first time we've been told to "follow the science" only to then find out it was 100% wrong.

History has taught us to be very skeptical of when that phrase is used.

See above about what my 55 year history has taught me. Seems your history has taught you something different, (maybe blame Texas). But I'll stick with my own insights.

 

[Michaels HiFi]

See above about what my 55 year history has taught me. Seems your history has taught you something different, (maybe blame Texas). But I'll stick with my own insights.

LOL. Yeah....Texas. That's it. OK Faucci.....I mean Feanor.

If you'll excuse me I've got new gear here to review that I'm going us use my own ears to listen to and make up my own mind how they sound. I don't need ASR to tell me what to think.

 

[2FarGone]

LOL. Yeah....Texas. That's it. OK Faucci.....I mean Feanor.

If you'll excuse me I've got new gear here to review that I'm going us use my own ears to listen to and make up my own mind how they sound. I don't need ASR nitwits to tell me what to think.

Amazing how defensive the ASR crowd is when people challenge being told what to think.

This entire measurement vs trust your ears debate strikes me as silly from its inception. Instrumentation and measurements are of great value in the design and development process, and they can also be useful in tracking down issues in a given acoustic environment. Some think they can use them to keep manufacturers honest, although I see less value here, since it seems improbable that a manufacturer will make claims that can definitively be proven wrong.

An high-quality audio system exists for only one purpose, however, that being to create a subjective illusion. To suggest that a listener’s subjective impression of the effectiveness of that illusion should take a back seat to instrument readings seems absurd.

Ultimately, there’s room and need for both, as has been recognized by some highly competent engineers such as Lynn Olson, and before him Daniel Von Recklinghausen. Both understood that while measurements have their place, in the final analysis it’s the way that creation sounds that determines whether or not they’ve been successful.

 

[Feanor]

Ultimately, there’s room and need for both, as has been recognized by some highly competent engineers such as Lynn Olson, and before him Daniel Von Recklinghausen. Both understood that while measurements have their place, in the final analysis it’s the way that creation sounds that determines whether or not they’ve been successful.

Yes, it's ultimately about enjoyment and satisfaction with one's system as well -- of course -- of the music.

As OP, I was originally talking about the improvements my ears tell me I'm getting from the use of FIR convolution filters. Further listening has confirmed for me to my own satisfaction that the results are well worth it, and I encourage others to try the approach and come to their own conclusions.