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+--- Thread: Room correction (/Thread-Room-correction)
RE: Room correction - markush - 01-Aug-2015
Any news / progress on this one?
RE: Room correction - ekovalsky - 06-Aug-2015
I do hope it is something that Devialet is seriously considering. My current rig is aging and not serviceable if something major fails and I've eyed Devialet as a potential replacement path. It would seem they have the processing power needed for implementation, any hesitation on the corporate end is probably related to the inherent difficulties/limitations in room measurement, coding a proper software interface and debugging it, and the tendency to endlessly tweak rather than listen. The latter in particular might be a disincentive for them since these units seem to be optimized for simplicity in operation, at least once initially configured.
I currently use a TacT Audio setup, it is digital throughout the signal chain. Input is PCM (optical, S/PDIF, or AES-EBU) up to 24/192. I use a modified Logitech Transporter as the source but just ordered an Aurender N10 to replace it. A TacT RCS2.2X is relegated to being a digital signal hub, measurement interface, and master volume control, all its processing is bypassed. The DSP is all performed in the four TacT S2150 amplifiers, each handles one driver group's crossovers, room/driver correction, target curve adjustment, and parametric EQ as well as time delay, phase, and gain matching in a horizontal quad-amp configuration; the specific filters for each amp are designed and programmed using (free) 3rd party TACS software. The outboard passive crossovers and electronic low pass sub crossover that came with my loudspeaker system are unused, rather the amps are directly connected to their corresponding driver groups. PCM>PWM conversion is performed at the final output with 150/300 watts into 8/4 ohm loads. Volume is controlled independently from the audio signal by reducing voltage on the output rails, so no loss of bits occurs. So basically, they are PowerDACs with variable output. The amps sounded excellent when new, and were further improved (substantially) by modifications including upgraded internal cabling, power supplies, and passive parts e.g. caps, inductors, and resistors... not surprising as they were built to a lower price point than the Devialet units. I have no doubt the Devialet amps would be significantly better.
Once one is accustomed to room/driver correction, there simply is no going back - physical room treatment can certainly help things in the reverberant range but does practically nothing in the modal range where all the bass problems occur. It is typical to see 20-30+ db swings over a few Hz in the low frequencies because of cancellation and augmentation effects determined by room dimensions, moving the speakers will change the frequencies of these nodes but not eliminate or significantly reduce them. Only with an infinite room - i.e. outdoor listening - do these issues vanish.
RE: Room correction - f1eng - 06-Aug-2015
(06-Aug-2015, 16:49)ekovalsky Wrote: It is typical to see 20-30+ db swings over a few Hz in the low frequencies because of cancellation and augmentation effects determined by room dimensions, moving the speakers will change the frequencies of these nodes but not eliminate or significantly reduce them. Only with an infinite room - i.e. outdoor listening - do these issues vanish.
This is not quite right. The frequencies are determined by the room dimensions, so moving the speakers does not effect the room modal frequencies, but it does effect the extent to which they are excited. Correct positioning of the speakers to minimise excitation of room modes is very effective (but may end up with the speakers in a location which is not domestically acceptable).
The node is the location of the null point of a resonant mode, and the anti-node that of the maximum fluctuation.
Correctly placed Helmholz resonator absorbers can pretty well remove the effect of room modes, too, but they are very big, need skilful setup and may well not be very domestically acceptable either.
Personally I much prefer the passive correction to active, but it requires a lot more work and may not be very visually acceptable.
RE: Room correction - ekovalsky - 08-Aug-2015
That's true, f1eng. Thanks for the correction.
In my previous house I spent many, many hours in a vicious cycle of moving the speakers and measuring. Changing the position of the speakers and/or microphone most definitely changed the measurements but there was no position where they looked particularly good. The measurements and perceived sound did not necessarily correlate either. I tried the 'golden ratio' and other favored placement strategies and ultimately wound up putting them where they struck a reasonable balance of aesthetics and acoustics. I bought several Mondo bass traps and they did surprisingly little, at least in the bottom few octaves where the most aberrations were present.
Here is a photo I found of a very nicely done room incorporating Helmholtz resonator absorbers and diffusers - so it can be domestically acceptable. If I ever build another house I will definitely consult with an acoustics specialist and try to do it right in the construction phase. Retrofitting a typical home theater or other room is never easy.
![[Image: imgext.php?u=http%3A%2F%2Fwww.engelholma...1e8542790e]](https://static.gearslutz.com/board/imgext.php?u=http%3A%2F%2Fwww.engelholmaudio.com%2Flevel3_4.jpg&h=6a2b9d3cab4a641dc0b81c1e8542790e)
One major drawback to active correction is that its effectiveness is inversely proportional to the size of the 'sweet spot' - optimal correction is only possible at one specific position. Also the ability to fix nulls is extremely limited, although they are not as audibly destructive as peaks that are easily handled.
I will say that measuring one's system for the first time is quite eye opening... First time I did it I was stunned, after being accustomed to typical +/- the 3dB manufacturer plots which are taken near field in an anechoic chamber.
RE: Room correction - JohnnySix - 12-Aug-2015
(27-Apr-2015, 23:22)markush Wrote: Didn't get this Informationen. Would ne Great if Otters could Write to devialet Support too!
I'd like to see Otters write to Devialet too.
RE: Room correction - markush - 12-Aug-2015
I just wrote to support about the current status of room correction, app update and providing upnp / dialog support for expert line. Let's see
RE: Room correction - NickB - 12-Aug-2015
(12-Aug-2015, 13:24)JohnnySix Wrote:(27-Apr-2015, 23:22)markush Wrote: Didn't get this Informationen. Would ne Great if Otters could Write to devialet Support too!
I'd like to see Otters write to Devialet too.
They would just ask for Electric Eels instead of mains leads
RE: Room correction - thumb5 - 12-Aug-2015
They'd just get the usual weasel words in reply...
RE: Room correction - markush - 24-Aug-2015
So obviously also Devialet is aware that room correction is an important feature - part of the reply was:
==
Please feel free to stay in touche with us on these points, especially room correction as it is a well demanded feature now.
==
Was surprised though to read at:
http://www.hifisenses.com/showroom/devialet-phantom-speaker-launch-interview.html
where it says:
==
As far as I know there is no room correction feature planned as we speak.
==
The article is a quite interesting read overall.
Anyway - will stay in touch with the support team and hope to see some exciting improvements coming up soon.
RE: Room correction - GuillaumeB - 24-Aug-2015
I'm hoping to test a Trinnov Amethyst in my setup soon so will report back on its room correction capabilities (which are supposed to be best in class). As it is a UPnP streamer/renderer (among a million other things!) I will be able to feed it directly into the Devialet.
For those that aren't familiar with the Amethyst see this:
http://www.hifiplus.com/articles/trinnov-amethyst-preamp/
I've heard some very positive reports across the Channel of others using the Amethyst with a Devialet. It's certainly got me very curious indeed!
Guillaume