Introduction to Expert Pro Sweet Room
Please note Devialet will not be able to advise on the room measurements and data analysis
Please kindly use this feature if you are already familiar with room correction.
1. Introducing Sweet Room
On September 30th 2020, a new software release for Expert Pro will be made public, including a new feature called "Sweet Room."
This feature is only available starting with the firmware 13.2.0 | DOS 2.2.6. You can look at the release note here
Sweet Room is a room correction module for Expert using a nine-band parametric equalizer - you will be able to modify the Expert Pro output signal and tailor it.
Before moving forward, you must measure the frequencies that need to be adjusted in your listening room. Sweet Room will apply concrete frequency settings based on the values that you need to modify (e.g., "I know my listening room is absorbing a lot the frequencies at 100Hz and 70Hz. Therefore, I'd like to add some gain to it").
Please note that our customer service won't be able to make measurements in your room for you to determine the corrections that need to be made. However, there's a big selection of software from different companies that can help you with this task.
To update your Expert Pro firmware and DOS version, please follow the instructions available on this article.
A template version of the eq.txt file ready to use is available to download in this article.
2. Deep dive into Sweet Room
Three criteria are to consider for adjusting your Expert Delivery:
- Frequencies (Frequency)
- Minimum: 0 | Maximum 20000
- Value in Hz
- Gain (dB_gain)
- no minimum nor maximum; however, a realistic value will be contained into -12/+12
- Value in dB
- Quality (Q_factor) > Please refer to this Wiki article.
- the minimum is 0 (can't be a negative value), no maximum. However high Q values have strong impact on phase variations and should be avoided for best sonic performance
Here you can see the file format. The editable fields of the file are marked in red and blue:
I've got my desired setting. How can I apply it to the Expert Pro?
Simply edit the eq.txt file and save it. Then copy and paste it to the root directory of your SD Card with your Expert configuration file.
Can I use this feature with my Expert (non-Pro)?
Sweet Room is only possible for Expert units with our Core Infinity card. Therefore, only Expert Pro can use this feature.
Does this setting apply to all my sources?
Yes, the Sweet Room settings will be applied to all your inputs. If you need to disable this setting for one specific input, please look at the next FAQ to toggle On/Off this setting.
How can I hear the difference when the Sweet Room is applied or not?
Thanks to our engineering team, you can add the word "REMOTE" into the eq.txt file to associate the button on the right of your Remote to toggle the EQ function On/Off.
Is there any risk when putting the file in my Expert or when the amplifier is reading the file?
Don't worry. You will be using a simple text file that can be edited with the notepad app in your PC or MAC to edit the information.
When the Expert is using the file, the amplifier will apply the selected criteria only when the entered values are correct. If there is a single line with a mistake, the amplifier will not use that profile.
Note: the file has to be named eq.txt - if the file name is different, the amplifier won't recognize it.
How can I make Sweet Room work on a Dual-Mono setup? (two amps chained together)
Each Expert Pro in the system should have an eq.txt file.
Two possible options:
- The Master file contains the EQ info for L and R channels. The same file has to be copied and pasted on the root directory of the Companion SD Card.
- Each amp has its own file with the EQ info for its specific channel (L or R).
Does the value to name each specific profile allow special characters?
The naming of the EQ configuration, as shown below, should not contain any space or special characters.
The editable field of the file allows for "Main" and "Alternate" values - What is this?
Once you have activated the Sweet Room in your amplifier, the Main value will be loaded and applied. You can also try an alternative profile with different values. Please use the fields under the tag "alternate" for that purpose.
Adding the word "Remote" into the file will allow you to switch between "Main" and "Alternate" profiles.
Is there any way to see on my Expert Pro if Sweet Room is activated?
If you navigate through the Expert main Menu (Long press on the Tone Button, then short press twice on the same button), you will find the DSPM spec with the "EQ" mention next to it.
Does Sweet Room apply EQ to my Preout ?
(Thanks Robert for this question) No Sweet room will only apply EQ on main output.
Will an external EQ interact with Sweet Room? in other word Does Sweet Room understand an adjusted signal via an external EQ (such as Roon or Jriver)
(Thanks Bernhard for this question) Expert Pro will consider any digital source as full scale, whatever the signal processing that is behind, and won't automatically adjust it. Sweet Room will apply the EQ whatever the signal recieved by your Expert Pro is
A part of corrections are not considered on my Expert Pro?
We identified that some SAM profil push a limit on the number of band adjustement with Sweet room. We are working to see how it can be fixed and deploy it later on.
In my Dual-mono setup, when I switched to Alternate correction, my Expert pro Companion remains on "Main" adjustement?
This is a bug, Companion is applying correctily the Alternates adjustement, but does not show it on its screen.
nice new feature!
One question: if you use any external EQ (e.g. in Roon or jRiver) you have to lower the general volume to avoid clipping if you use an EQ with a positive gain.
Is this handeled automatically here (enough headroom) or do we have to do that as well ?
Would the EQ setting also apply to my Analog Pre-OUT (Which I use for my headphone amplifier) ?
Many tnx for your help.
The EQ is only applied on the main speaker outputs. The analog preout remains flat in frequency which is needed to feed your headphones amp.
Any incoming digital source is considered full-scale, whatever processing occuring in the source (ex. Roon EQ). In case an EQ is applied prior feeding the amp with the modified signal, the amp cannot be aware of this and will always deal with the incoming stream as a full scale one.
Sweet Room allow for local headroom management via the gain setting. Although Sweet Room is a stereo processing, we strongly recommend to set the same static gain on both Left and Right channels (otherwise balance issues). Best is to set the overall gain to the same value than the highest EQ gain. For example, if a band is used to apply positive gain, say 3dB, on a given frequency, best is to set the global gain to -3dB. This will ensure no triggering of our compressor/limitor.
When will it be possible to edit the EQ Settings directly via the web interface - instead of the time-consuming way via SD card and restart of Devialet?
This is not applying all 9 bands of filters, filters after 5 are ignored it seems. Multiple people reporting this on the forum.
Good Job! Thanks Devialet bringing this new Sweet Room function. That's what Core Infinity is built for. I am new to the room correction but I have already ordered a UMIK-1 for measuring. Haha.
Sweet Room stops working as soon as you activate the pre out in combination with a highpass for the speakers.
I know it is not active for the pre out itself, but why does it also stop working for the main speakers ?
When the preout is engaged then the whole amp toggles to the alternate series of filters. That is why you need to duplicate your EQ settings in alternate mode to make it active also when the preout is on. Please refer to example 4 of our tutorial.
All bands should work. Send me both eq and configuration file by email for inspection. There may be some conflicting directives. My email is mp at devialet.com
@Mathieu: Any word on the web interface? (in general for editing settings of the Devialet and in special for the EQ) ?
"The EQ is only applied on the main speaker outputs. The analog preout remains flat in frequency which is needed to feed your headphones amp."
Can this please be made optional, so that it can correct subs as well. I don't use these options for headphones, but if I did I would be using EQ with them as well, as I do currently via Roon.
@Kevin: EQ on the analog preout: can this be optional.
I can see that you would be using EQ for a sub, but what is the use case for headphones ? There is no "room correction" necessary for headphones I guess. I do apply treble and bass adjustments, but that is indeed optional for the analog pre-out. Works for me.
@Robert Re:Headphone EQ
A lot of headphones need response corrections, some quite complex, and sweet room could do this well. If you look at the measurements and corrections produced by someone like oratory1990 you can see that many of these are beyond simple bass and treble controls.
Applying custom EQ on the preamplified output would require to free some DSP power. It is currently not feasible with the current software release. If ever we manage to make new DSP resources avaible thanks to code optimization then we'd surely make that available to the main speakers output. If custom EQ is required for a given headphones, this is a headphones amplifier's task. Well, it will all depend on how much CPU power we might optimize
@Mathieu: Many owners are being advised by other owners to use a miniDSP UMIK-1 together with the Room EQ wizard (REW) software as a way of measuring their respective rooms.
REW provides a number of available Equaliser types from which to generate appropriate EQ filters. These Equaliser types mainly fall into two groups dependent on the calculation of the bandwidth in Hz between the half gain points
1) Bandwidth = sqrt(gain)*centre frequency/Q
2) Bandwidth = centre frequency/Q
Using the supplied filter examples and the included APL frequency screen images, I believe that Sweet Room uses option 1.
However, it would be comforting to have this assumption confirmed or corrected.
Your assumption is correct : the resulting bandwidth can be computed according to formulae n1 : bandwidth = sqrt(gain)*F/Q.
I really like the SweetRoom feature, but I found using text file and frequently insert/pull SD card then power off/on the Expert PRO is very time consuming. Any chance in the future this can be saved using the built-in web interface? So we can edit and save using the browser and then click on a apply button to make the change takes effect. Today I spent 3 hours on it, a lot of time are copy/paste and power off/off amp, it is really inconvenient.
Could you give us an update about bug fixing, improving / features ?
Does applying 'Sweetroom' compromise in any way, the excellent low distortion specification of the expert pro amps.
Sweet Room does not alter the distortion and other audio figures of the amplifier, appart from its frequency and phase response of course
Are the gain settings for the left or right channel in addition to the gain that I have already set for my speakers? Or does the value in the EQ file overwrite the speaker setting?
The source gain settings and the gain settings from the speaker menu are independant of Sweet Room directives.
I'd recommend to merge the speaker gain settings into the Sweet Room parameters for clarity reasons (identical mathematical results for both methods)
A wise decision to start this thread with a word of caution regarding room correction. It is a complex undertaking and one that has had me banging my head for awhile. I applaud Devialet's willingness to release Sweet Room as is. It's a wonderful glimpse of what is possible with the Expert Pro, but it is cumbersome at best. I'm hoping you can at least hint as to whether Devialet intends to expand and improve on Sweet Room - in particular, the need for a more robust front end rather than the current slow and error-prone process to manually edit and reload settings via SD card.
Mathieu or Sebastian, I doubt I'll get you to talk futures, but is there any insight you can offer for those of us that would love to see Sweet Room evolve into a far more useful tool? I fully understand the need for external tools like REW and a depth of knowledge to properly measure and assess room response. But Sweet Room needs an intuitive and dynamic front end to simplify response comparisons in real time.
Any insight is appreciated! Thank you.
A PART OF CORRECTIONS ARE NOT CONSIDERED ON MY EXPERT PRO?
When do you ha e an update available?
Please sign in to leave a comment.