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 was made public, including a new feature called "Sweet Room."
This feature is only available starting on FIRMWARE 13.2.0 | DOS 2.2.6 and above. You may view the release notes HERE.
Sweet Room is a room correction module for Expert using a nine-band parametric equalizer. With it, you are able to modify the Expert Pro output signal and tailor it to your liking.
Before proceeding, 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 most of the frequencies at 100Hz and 70Hz. Therefore, I'd like to add gain to those bands specifically").
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 large 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 considered when 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:
FAQ
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I'VE GOT MY DESIRED SETTING. HOW CAN I APPLY IT TO THE EXPERT PRO?
Simply edit the “eq.txt” file and save it. Copy and paste that file in the root directory of your SD Card with your Expert configuration file.
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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.
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DOES THIS SETTING APPLY TO ALL OF MY SOURCES?
Yes, the Sweet Room settings will be applied to all of your sources. If you need to disable this setting for one specific input, please reference the next FAQ to toggle this setting on/off.
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HOW CAN I HEAR THE DIFFERENCE BETWEEN SWEET ROOM BEING ENABLED AND NOT?
Thanks to our engineering team, you can add the word "REMOTE" into the “eq.txt” file to map the button on the right of your Remote and toggle the EQ function On/Off.
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IS THERE ANY RISK WHEN PUTTING THE FILE IN MY EXPERT OR WHEN THE AMPLIFIER IS READING THE FILE?
There is no need to worry. You will be using a simple text file that can be edited with the notepad app in your PC or MAC, so there is no risk to your system as the file is being read.
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 must be named “eq.txt” - if the file name is different, the amplifier will not recognize it.
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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 both the L and R channels. Thus, the same file has to be copied and pasted on the root directory of the companion SD Card.
- OR each amp has its own file with the EQ info for its specific channel (L or R).
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DOES THE NAME FOR EACH SPECIFIC PROFILE ALLOW SPECIAL CHARACTERS?
The naming of the EQ configuration, as shown below, should NOT contain any spaces or special characters.
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THE EDITABLE FIELD OF THE FILE ALLOWS FOR "MAIN" AND "ALTERNATE" VALUES - WHAT IS THIS?
Once you have activated Sweet Room on your amplifier, the Main value will be loaded and applied. You may 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 using the remote.
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HOW DO I SEE IF SWEET ROOM IS ENABLED?
If you navigate through the Expert main Menu (Press and hold the Tone Button, then press the same button twice), you will find the DSPM specification with "EQ" noted beside it.
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DOES SWEET ROOM APPLY EQ TO MY PRE-OUT ?
No. Sweet Room will only apply EQ to the main output.
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WILL AN EXTERNAL EQ INTERACT WITH SWEET ROOM? IN OTHER WORDS, DOES SWEET ROOM ACCOUNT FOR AN ADJUSTED SIGNAL VIA AN EXTERNAL EQ (SUCH AS ROON OR JRIVER)?
The Expert Pro will treat any digital source as full scale, regardless of the signal processing applied behind it, and it won't automatically adjust it. Sweet Room will apply the EQ to the signal received by your Expert Pro, regardless of its source or characteristics.
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SOME CORRECTIONS ARE NOT AVAILABLE ON MY EXPERT PRO
We identified that some SAM profiles place a limit on the number of band adjustments with Sweet Room.We are actively working to determine how it can be resolved and plan to implement the solution at a later time.
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IN MY DUAL-MONO SETUP, WHEN I SWITCHED TO ALTERNATE CORRECTION, WHY DOES MY EXPERT PRO COMPANION STILL REMAIN ON "MAIN" ADJUSTMENT?
This is a bug. The companion is correctly applying the Alternate adjustments but does not display them on its screen.
Comments
25 comments
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.
Hi Robert,
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.
Hi Bernhard,
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 ?
Hello Bernhard,
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.
Hi Kevin,
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
Many thanks
@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.
Hi Alan,
Your assumption is correct : the resulting bandwidth can be computed according to formulae n1 : bandwidth = sqrt(gain)*F/Q.
@Mathieu,
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.
Thanks again!
@Mathieu,
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.
Thanks
Robert
Dear Robert,
Sweet Room does not alter the distortion and other audio figures of the amplifier, appart from its frequency and phase response of course
Best regards
Mathieu
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?
Dear Carsten,
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)
Best regards,
Mathieu
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?
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