Simple convolution advice please

Hi there

I am a total newbie with no audio engineering knowledge.
In fact I have a small room (15m2) but had to install some big speakers in it (B&W CM8 powered with a BS powernode 2i). The overall audio is good but I kinda feel that the sound is harsh in that listening room with bass, mids and treble mixing together. I am wondering if a convolution filter can help to improve this.

I tried to use REW but I feel that there are many settings, many measurements to do and I certainly will not do this right.

Is there a very simple convolution software (like Sonos trueplay) that I can use to see if the sound improves in my room?
Or do you have any advice for me knowing my audio setup above?

Thanks for your help and advice

I’m not sure there is anything that much simpler than REW. At the end of the day you need a calibrated mIc to produce a room impulse file that roon (or any other playback software) can interpret. There are several commercial products out there with slightly improved usability but they all seem to follow a similar process.

Maybe Dirac bundled with a hardware device from someone like miniDSP will simplify things enough but then you will start making an investment you are probably not ready for yet if you are just testing. Maybe others have other suggestions.

I don’t know if you saw this link? It does a very good job of explaining the REW process:

One thing that can further simplify the process is just taking one or two measurements at the listening position using the moving microphone method. Many convolution softwares require you to take multiple fixed measures (e.g. Dirac requires 9 or more) and that can be difficult without additional equipment like a microphone beam. This video starting at about 8.12 explains how to take measurements with a moving mic (literally waving the mic around).

Using this method REW will average dozens of measurements in a single pass so that multiple measurements converge. I did 120 averages as in the video for each speaker. Takes less than a minute for each speaker and I would say I had working convolution filters uploaded to roon in about 15 minutes or so. The end-to-end process does look very intimidating and complex but once you have done it once following the guide above you realise it is very straightforward. You will be glad you took the time. It has done wonders for my system taming an annoying bass boom on certain tracks and bringing mids and highs more forward in the mix.


I will look into this
Many thanks

Well I will buy a USB mic and I will start tinkering with these convolution filters. Although it appears hard to understand for someone without audio engineering knowledge like, I will try to learn step by step.

In the meantime, I tried this and sound was already more coherent in my room. My problem was the mids I think as they are very present in the CM8s but too disorientating in my small room.

Does this look like something coherent? Or what I did is nonsense?

Unless you are very lucky all rooms will have standing waves, reinforcing or sucking out certain frequencies. The difference once you get a mic is that you will be able to measure that. It will be interesting once you make your first measurements if the results support what you are hearing and what you have done by hand with PEQ.

Absolutely I will keep you posted. Your links and how-to are very useful. Many thanks
And also with the convolution filter set, maybe many other things should be handled such as reflections for example and roof height
I think my room is a complicated one, marble floor, 2m80 of height under roof, not too many furniture… But I cannot change my room
Maybe I should buy a carpet and put some curtains…

Note that if you haven’t already come across them there are professionals who can help with this from measurements that you supply - many of us have been very happy with Home Audio Fidelity.


Nice! I did not know this company and it appears that it is located in my city :slight_smile:

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Ask for a gent named Theirry …he’s a great guy to help you with Room Correction…the convolution filters are easy to install in Roon once Theirry builds them for you after getting your REW measurements.

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Yeah that’s the spirit

But I am just wondering if I am not making too much of it. I don’t have 100k gear like I can see in some forums. I very often listen to my music in headphones. My speakers are just BW CM8 powered by a Bluesound Powernode 2i in a room complicated to drive. But I am just looking to a way to improve my speaker listening when I sometimes enjoy it. And this will cost at least 200e (100e for the mic and 100e for the convolution filter)…

I would also kindly ask you for another advice. Since I have no USB dac connected to my laptop but only the Powernode 2i, can I use the test album provided by Qobuz « 12 tracks to adjust you hifi system » which is already on my NAS library to make the measurements?

I can’t speak for the Qobuz album but Thierry will send you test tracks that you can just play from your Roon server - no need for a USB dac - you do need a laptop with USB to do the mic recording though (I use a very old netbook running Windows XP).

As to whether it’s worth it to you, probably best way to answer that is with a trial, if you’re buying the mic anyway. If you give Thierry a couple of test tracks he’ll run the filters over them manually so you can hear the difference before parting with your cash.

Nice. Thanks
I will look into all this tomorrow

I don’t think the benefits have much to do with the pricepoint of the equipment. It is more the geometry of the listening room. I have the B&W 802 D2’s powered by Mark Levinson and Krell amps. If I swapped the speakers out for your CM8’s I am going to get much the same standing waves in my listening room that I would still want to correct. In fact I can see that I get the same standing waves with a small pair of powered KRK Rokit 5’s and they are at a completely different price point to the 802’s.

I read reports that the convolution effects are subtle. I do not find them subtle at all. The 802’s were shipped across Europe from a large open plan modern apartment with concrete floors and vaulted sloping ceilings and in hindsight an almost perfect acoustic. I am now in a period apartment with suspended floors and much smaller conventional room and ceiling layouts. Home brewed convolution is giving me close to 90% of the previous acoustic and realistically is the only way I can achieve that at the moment. I was unaware of the HAL service so I am going to go for it and fingers crossed I can get 100% of the acoustic I remember, maybe better.

You’ve found some PEQ adjustment helps (and that dip looks fine to tame pronounced mids) so I suspect convolution of a room WAV may assist. It mainly helps untangle lower frequencies because once you get above 5k or so wave artifacts are more closely spaced and head movement can change things.

Have you looked at room treatments ? Even something as simple as wall hangings or soft furnishings on first reflection points can make a substantial difference.

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Gotta be easier than using trinnov sp2 I bet…I would vote for HAF too from feedback I have seen here. At least with doing correction in roon it’s all in the digital domain.

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Many thanks

If you insist to trade speakers, I can accept :smiley:

Ha Ha :smile:. Those are keepers. I don’t change my equipment very often.