Minidsp Flex Review (Audio DSP)

[Robocop]

Run minidsp at 0 db volume. Thats what I do and control volume from preamp. Its worked for me the same as your drawn circuit.

 

[antcollinet]

Hello everyone, I am new to the forum and have been ready through all the posts (1/3 way through), reading the device specs, and also the extremely helpful documents on the miniDSP website. I have summarized in the drawing my understanding today on how to integrate the miniDSP into a 2.1 system but I am still unclear in some areas, such as, volume management.

If you have a moment, please review my drawing and let me know what I missed or misunderstood. Thanks.

Hi

It will work fine as drawn.

The only thing you could consider - if you are not using the preamp for phone pre (ie if your phono pre is separate sending line level to your preamp), then you could dispense with the preamp, and put all three sources into the Mini DSP flex (as long as you have different interface options for CD and Streamer), then using the MiniDSP for volume.

Personally I run the MiniDSP at -3dB just to eliminate any risk of interasmple overs. But this is probably un-necessary.


EDIT - I see the preamp has a phono input that I guess you are using, so you can ignore this suggestion.

 

[Calypso1]

Hi

It will work fine as drawn.

The only thing you could consider - if you are not using the preamp for phone pre (ie if your phono pre is separate sending line level to your preamp), then you could dispense with the preamp, and put all three sources into the Mini DSP flex (as long as you have different interface options for CD and Streamer), then using the MiniDSP for volume.

Personally I run the MiniDSP at -3dB just to eliminate any risk of interasmple overs. But this is probably un-necessary.


EDIT - I see the preamp has a phono input that I guess you are using, so you can ignore this suggestion.

Thanks for the tips. Yes, correct the only reason today for keeping the preamp is for phono input support; mc and mm. I may remove it later. Will definitely take your suggestion and run the MiniDSP at -3dB or at least listen for a difference.

 

[Robocop]

Personally I run the MiniDSP at -3dB just to eliminate any risk of interasmple overs. But this is probably un-necessary.

I believe this issue was solved with this update from minidsp web site:

18/09/2023 - Rev 1.1.11 18/9/2023, 1:00:56 pm
DSP Firmware
- [All Models] Volume control moved before ASRC in DSP chain to help against potential distortion caused by intersample peak.

 

[AaronJ]

Run minidsp at 0 db volume. Thats what I do and control volume from preamp. Its worked for me the same as your drawn circuit.

Agree with this advice. This is how I use my minidsp flex, except it’s in the pre-out-main-in loop of my integrated. One other word of caution is I recommend placing a high quality analog pot between the flex and amplifier to protect your speakers. My flex has output max volume when making some changes in Dirac live which is problematic when fed directly into a power amp. Something like a Schiit Sys, JDS Labs OL switcher, or even a Nobsound switcher are all good choices for the application. I use the JDS Labs at 12 o’clock.

 

[antcollinet]

I believe this issue was solved with this update from minidsp web site:

18/09/2023 - Rev 1.1.11 18/9/2023, 1:00:56 pm
DSP Firmware
- [All Models] Volume control moved before ASRC in DSP chain to help against potential distortion caused by intersample peak.

That only helped by allowing you to turn the volume down a little to avoid them. Previously turning the volume down when it was later in the DSP chain couldn't help.

Having said that - I've never heard anything I could attribute to inter-sample overs in my life. I suspect they are one of those things audiophiles worry about for no reason.

 

[mdsimon2]

I believe this issue was solved with this update from minidsp web site:

18/09/2023 - Rev 1.1.11 18/9/2023, 1:00:56 pm
DSP Firmware
- [All Models] Volume control moved before ASRC in DSP chain to help against potential distortion caused by intersample peak.

They reverted this behavior in later updates as some users had noise issues. I am not sure if the ASRC gain structure update is still on the table.

I also confirmed that the newest firmware still clips when feed intersample overs, regardless of volume position.

Michael

 

[Robocop]

They reverted this behavior in later updates as some users had noise issues. I am not sure if the ASRC gain structure update is still on the table.

I also confirmed that the newest firmware still clips when feed intersample overs, regardless of volume position.

Michael

Interesting I'm also not sure and never got a reply from minidsp about reinstating ASCR gain at update Rev 1.1.14. I personally never had any problems when they did move the gain and in fact felt it sounded slightly better(1.1.11). Update 1.1.11 appeared to cause problems with some older other models.

Did you ever measure this at the time of this update 1.1.11 to see if it clipped?

Have to say I have never heard it or if its infrequent enough to.

Robert

 

[mdsimon2]

Interesting I'm also not sure and never got a reply from minidsp about reinstating ASCR gain at update Rev 1.1.14. I personally never had any problems when they did move the gain and in fact felt it sounded slightly better(1.1.11). Update 1.1.11 appeared to cause problems with some older other models.

Did you ever measure this at the time of this update 1.1.11 to see if it clipped?

Have to say I have never heard it or if its infrequent enough to.

Robert

I tested the beta firmware before it was released. With the beta firmware you could send a +3 dBFS signal and if you reduced the main volume by 3 dB it would eliminate intersample over clipping. Important to note it was only the main volume control that had this effect, changing the gain on the input or output channels would not.

I never had a chance to test the released 1.1.11 update.

Michael

 

[Calypso1]

Agree with this advice. This is how I use my minidsp flex, except it’s in the pre-out-main-in loop of my integrated. One other word of caution is I recommend placing a high quality analog pot between the flex and amplifier to protect your speakers. My flex has output max volume when making some changes in Dirac live which is problematic when fed directly into a power amp. Something like a Schiit Sys, JDS Labs OL switcher, or even a Nobsound switcher are all good choices for the application. I use the JDS Labs at 12 o’clock.

Could this also work?

https://www.amazon.com/Audio-Controller-Control-attenuator-RC11/dp/B08TBMP54X/ref=sr_1_8?keywords=Volume+Control+for+Speakers&qid=1704662738&sr=8-8

 

[Calypso1]

Hi

It will work fine as drawn.

The only thing you could consider - if you are not using the preamp for phone pre (ie if your phono pre is separate sending line level to your preamp), then you could dispense with the preamp, and put all three sources into the Mini DSP flex (as long as you have different interface options for CD and Streamer), then using the MiniDSP for volume.

Personally I run the MiniDSP at -3dB just to eliminate any risk of interasmple overs. But this is probably un-necessary.


EDIT - I see the preamp has a phono input that I guess you are using, so you can ignore this suggestion.

Quick question. Moving the MiniDSP before the preamplifier would alleviate any risk on damaging peaks ever being released to the amplifier. Thoughts? No need for a volume control box.

 

[antcollinet]

Quick question. Moving the MiniDSP before the preamplifier would alleviate any risk on damaging peaks ever being released to the amplifier. Thoughts? No need for a volume control box.

With the disadvantage that you'd no longer correct your turntable (unless you also invested in a phono pre.


Plus even with the analogue pot (your preamp) before the flex you are still protected. The Flex (unless you program positive gain on the inputs) won't output more than your pre-amp inputs.

 

[dom_st]

Anyone has the impression the minidsp flex is getting quite hot? I measured it with a infrared device and the hottest spot on the top of device is around 41°C and on the bottom, even warmer with around 48°C (hottest spot in the last third of the device). After maybe 1-2h runtime, standing freely not covered. I think this is borderline ok, but feels wrong. I have now disconnected the output cables to see if that could have a influence. The device itself is basically in standby, not configuring it, not playing music through it.

 

[Robocop]

Anyone has the impression the minidsp flex is getting quite hot? I measured it with a infrared device and the hottest spot on the top of device is around 41°C and on the bottom, even warmer with around 48°C (hottest spot in the last third of the device). After maybe 1-2h runtime, standing freely not covered. I think this is borderline ok, but feels wrong. I have now disconnected the output cables to see if that could have a influence. The device itself is basically in standby, not configuring it, not playing music through it.

Hi I just checked mine(Flex balanced) on the top and its 29C with ambient air temperature inside room at 24C at midday and midsummer in New Zealand. It did seem to run hot when I first received it but has settled at this temp. I run all balanced connections to 2 subs and monitors. I do have a separate earth wire attached from Flex cabinet to house ground. I also leave it permanently on. Also have latest software update onboard.

Perhaps check all connections first on cables. Don't forget to turn amps off before disconnecting any plugs. Update software if you haven't done this. Turn off and remove power to Flex wait for 5 mins or so and reconnect. This reboots it. Others may have further suggestions otherwise Minidsp support.

Robert

 

[TheBatsEar]

Anyone has the impression the minidsp flex is getting quite hot?

I think mine is a bit warmer than expected as well, it feels warmer than any other device i have running. I always wondered why they didn't put a few holes into the case on top and the bottom.

 

[vicenzo_del_paris]

I think mine is a bit warmer than expected as well, it feels warmer than any other device i have running. I always wondered why they didn't put a few holes into the case on top and the bottom.

2x4hd/ddrc24 unit i had in the past was quite warm.
But The flex i had previously was never warm at all.
My current Flex HT does not at all when using stereo sources. It might warm a little bit when using hdmi, but still very reasonable.

 

[mata7]

hi guys I hope some one can help me out please, my Minidsp 2x4 HD just stop working after 4 or 5 years, so I need to get a new one, now I have 5 subs and I was considered the Minidsp Flex Eight but I'm confuse because I don't see any analog in, I only need it for subs, so how do I make this work like I do on my 2x4hd, thanks

 

[Chagall]

hi guys I hope some one can help me out please, my Minidsp 2x4 HD just stop working after 4 or 5 years, so I need to get a new one, now I have 5 subs and I was considered the Minidsp Flex Eight but I'm confuse because I don't see any analog in, I only need it for subs, so how do I make this work like I do on my 2x4hd, thanks

It's impossible to use Flex Eight like you used 2x4 HD because it doesn't have analog inputs.
I think these are the options for Flex and Flex 8 in your case. If that doesn't work for you, just get 2x4 HD again.

EDIT: 2x4 HD also has only 4 analog outs. So that won't work for 5 subs either.

 

[diablo]

hi guys I hope some one can help me out please, my Minidsp 2x4 HD just stop working after 4 or 5 years, so I need to get a new one, now I have 5 subs and I was considered the Minidsp Flex Eight but I'm confuse because I don't see any analog in, I only need it for subs, so how do I make this work like I do on my 2x4hd, thanks

I sometimes need analogue in to my Flex Eight. I bought a converter to feed into the SPDIF input -

Blustream ADC11AU Analogue to Digital Audio Converter (ADC)

Blustreams ADC11AU is designed to convert left/right analogue stereo audio into either coaxial or optical digital. Product Code - ADC11AU

www.futureshop.co.uk

It seems to work pretty well.

The Flex HTx has eight channels and analogue inputs -

miniDSP Flex HTx

miniDSP Flex HTx, 400MHz Sharc DSP audio processor, toolbox for subwoofer or multiway speaker tuning, USB/HDMI ARC/EARC, Optional Multichannel Dirac Live license for room correction,

www.minidsp.com

- but that's probably overkill for your needs.

 

[mata7]

thank you diablo, do you use your flex for subs? is there any problem to add delays if i use the adc? thank you, yes the htx is a lot of money and really don't need it