Convolver in the DSP

[ogs]

Hi, first post on this forum. I salute the people behind this initiative!

I've corresponded via email with Devialet on the subject of digital room correction. I also sent sample filters to them in November 2011 (Manuel de la Fuente) for developers to test. I purchased my D-Premier in January 2012 partly based on the feedback I received from Quentin Sannié and Manuel de la Fuente

The first response from Devialet on the subject is from May 24 2011

"It is possible to load a room or a speaker correction in the DSP. We will provide the first DSP tool in a few weeks in the Configurator.
I hope this can help you.
Best regards,
Quentin

Quentin SANNIÉ"

The next response from Devialet on the topic was this from August 6 2011:

"Regarding speaker or room correction options in the DSP, we finally decided not to include it in this version of the configurator, both because we needed more time and because it is risky option to put in everybody's hands.
Nevertheless, we can provide some "on demand" configuration offering active cross-over, or some DSP corrections. If you are interested to try this, please give us precise information about your filtering requirements. If they are compatible with the current structure of the DSP, we can make them for you.
I hope this helps.
Sincerely yours,

Manuel de la Fuente"


Here is a snip from September 5 2012

"I do NOT know yet when the room correction will be available. All I know is that it will come.


Best regards,

Thierry"

And the latest response regarding DRC from Thierry dated March 7 2014:

"We have at this point no fixed plan to introduce room correction in our products. We are working at the moment on other topics that you will discover in the months to come.


Best regards,

Thierry"

So in spite of what Devialet had planned back in 2011/12 they now seem to have abandoned the idea of an internal convolver in the DSP for use with third-party filters from for example Audiolense or Acourate. This is really bad news for those of us that use DRC to improve playback quality. I was looking forward to using all sources with DRC filters running in the amp. I have postponed my return to vinyl waiting for this.

I think it is easy for Devialet to enable a convolver function in the new DSP. Actually it is probably there already as I believe SAM is done this way. SAM is no doubt an exellent feature and I look forward to use it with the LS50 speakers I have on order, but it only corrects the speaker and speaker/amp interface and not the equally important speaker/room interaction.
I do understand Devialets worry that people will use inadequately designed filters and thus create bad results and reputation for Devialet. For a user like myself with many years of experience using DRC I would suggest to Devialet they find a way to support select users with a convolver function in the internal DSP. If the filter format needs to be specific I am certain the clever guys behind the above mentioned Audiolense and Acourate will include a "Save for use with Devialet..." in their programs based on filter specification from Devialet.

[Nightmare]

Extremely poor development :-(

[Borgen]

I agree this is sad and disappointing. On one side I really like what Devialet is trying to do and wish them all the best in their attempts, on the other side I feel kind of let down based on "promises" they've made in emails and external communication. I bought into Devialet because of their DSP/ upgrade story and roadmap with the promise of "if you buy a D-Premier you get a stream of improvements over the years". Kind of disappointing that 18 months later I figure out that I need to pay significant money to do a hardware upgrade not to be left behind and secondly, that the key feature I really wanted is not on the roadmap any longer.

That said, I think there are basically 3 alternatives around convolver:

a) Devialet accepts that there is a small set of customers that REALLY want this and makes it possible to install convolver files that these customers generate on their own, not taking any responsibility for sound quality or issues. Any microphone or quality issues are entirely left for the customers to handle. They probably need to make it sufficiently "cumbersome" to avoid everyone doing this and creating negative feedback around this feature and potential quality issues.

b) Devialet makes a turnkey solution for this with recommended tools/ microphones to use OR make a solution that works with one of e.g. AudioLense or Acourate and their recommended tools/ processes/ guides.

c) Presuming SAM require some form of convolver files to be downloaded/ installed, someone will at some point reverse engineer this format and make it possible to generate custom "SAM files" unless Devialet blocks this by e.g. cut-off frequencies in firmware.

The flaw in Devialet's arguments around DRC and sound quality is that presumably all of us asking for this already run convolver filters in JRMC or similar. Moving this out of the PC and into a DSP with higher sampling rate can hardly reduce sound quality.

[f1eng]

Have any of you guys keen to add this function asked for a custom filter to be done specifically for you?
Maybe it is not so easy now there are a lot more owners, but back in May 2011 I would be surprised if they hadn't looked into doing a specific configuration if you asked, they were certainly doing this for other owners (and some of the "specials" got included in later firmware updates). OTOH I am sure these requests were much more simple to implement than yours, and one of the reasons for extra DSP in the new models was to deal with more complex configurations so perhaps this was not possible with a D-Premier.

[ogs]

Have any of you guys keen to add this function asked for a custom filter to be done specifically for you?

It turned out the filters Devialet could provide at the time was amplitude correction only. As DRC is more than just an equalizer I did not try this.

[ogs]

Devialet still has a post in their knowledge base on Room Correction.
https://help.devialet.com/entries/236806...correction
I guess we will see this option enabled at some point. Maybe after all the work they have related to SAM.

[Divasson]

I have installed this afternoon the trial version of Dirac Room correction, and done the set up (which is "for dummies", as they say). I set it up for "sofa", and I had to take 9 readings in different parts of the sofa. This is to make sure that the bass is even everywhere in the listening area. The set up system is very clear in which is the "reading" for the sweet spot. It later shows why: the imaging and soundstaging is magnificent for that point.

I applied the objective curve suggested by the system.

Prior to that, I had reviewed with REW the frequency response in that spot - pretty weird. No wonder there was a "hole in the bass", and the highs were too piercing.

I have been listening to it for a couple of hours, and I see nothing negative, and several improvements.

- More even, controlled, full, clear bass.
- Gone the piercing highs.
- Spectacular soundstage in the sweet spot.
- Music sounds sweeter, less fatiguing.

I continue. 389 € is a stretch, and I can only use it with the Mac (not with vinyl or other inputs), but...

[ogs]

I have installed this afternoon the trial version of Dirac Room correction, and done the set up (which is "for dummies", as they say). I set it up for "sofa", and I had to take 9 readings in different parts of the sofa. This is to make sure that the bass is even everywhere in the listening area. The set up system is very clear in which is the "reading" for the sweet spot. It later shows why: the imaging and soundstaging is magnificent for that point.

I applied the objective curve suggested by the system.

Prior to that, I had reviewed with REW the frequency response in that spot - pretty weird. No wonder there was a "hole in the bass", and the highs were too piercing.

I have been listening to it for a couple of hours, and I see nothing negative, and several improvements.

- More even, controlled, full, clear bass.
- Gone the piercing highs.
- Spectacular soundstage in the sweet spot.
- Music sounds sweeter, less fatiguing.

I continue. 389 € is a stretch, and I can only use it with the Mac (not with vinyl or other inputs), but...

Yes, how nice it would be to run the correction in the amplifier! You'd be free to use all inputs and select the best streaming service without having to consider if it is compatible with your room correction setup.
I've used Audiolense filters for a long time with both Jriver and Brutefir. I can not imagine living without room correction!

[markush]

To me room correction is a necessity as this influences overal sound quality to a vast extend. When reaching out to Devialet support I got the feedback the room correction should finally be available by Q3 2015! Unfortunately couldn't get any further details about features etc.

[ogs]

To me room correction is a necessity as this influences overal sound quality to a vast extend. When reaching out to Devialet support I got the feedback the room correction should finally be available by Q3 2015! Unfortunately couldn't get any further details about features etc.

So Q3 2015? That is very encouraging. Should be in an autumn firmware update then. I'm really hoping Devialet will keep this promise..