miniDSP Flex

[mdsimon2]

I had the house to myself and the day off work, so I dove in deep with Dirac today. Here how the Flex fits into my system:


View attachment 183429
After first spending a bunch of time comparing crossover points and listening to them, I settled on the LR 24dB/oct at 80 Hz for crossovers. I also put a BW 24dB/oct high pass filter on my subs at 18 Hz. They are only 8" and there is no point wasting any effort down there. The first test was whether DSPing the subs makes any difference. Here are my subs with and without EQ:

View attachment 183426

And the pic below is what dirac corrected each one to. Ha! EQing the subs was a waste of time other than for learning. This is freaking impressive! I think it's fair to say any differences in this graph are from me moving the mic during the different measurements and process. Dirac apparantly knows what it wants to do with my setup in my room and willl do it no matter what I did to my subs:

View attachment 183427
This is the uncorrected respose vs the default correction that Dirac does with my system from nothing but crossovers set. I think it's quite impressive and it's quite a bit better than I was able to do on my own given only 10 bands of EQ per channel in the Flex:

View attachment 183430

EDIT: this is where I come back to this post and mention that after careful A/B listening, the Dirac default curve sounds better than the curve I edited myself. The "flatter" response does not actually sound better. It's barely different, and a little worse. I'll leave the comments in place anyway. By making quite a few corrections to the target curve, I was able to get a flatter response than I was ever expecting to pull off in my room. This pic shows the adjustments to the target curve in Dirac:

View attachment 183431

Every single point on the curve was confirmed and dialed in over dozens of REW measurements. You don't have to dial in any numbers, just ad points and drag. You can zoom in super close if you need also. I think the interface is pretty slick. The comparison below shows how much I was able to dial it in on my own on top of Dirac:

View attachment 183432

And because comparisons are fun, below is the original uncorrected response from the image above compared to the final corrected response I was able to get in Dirac alone. I have zero EQ settings in the miniDSP. It sounds fantastic! Dirac was 100% worth the $200. Zero question at all in my mind.

View attachment 183438


Yep, and this is definitely as loud as I'd ever listen on this system. I didn't test louder because I have no interest in damaging my subs for cool graphs.

View attachment 183439

I spent many hours on this today, but the final result was generated by:

1. Set delay/levels/crossovers in miniDSP plugin
2. Run Dirac, export correction default curve to Flex
3. Measure in REW and see what it did
4. Adjust target curve, save to Flex, then repeat between this and step 3 until happy (EDIT: this proved to be a waste of time and a worse subjective result)

If I had just done that from the start, less than 2 hours.

Have you tried measuring the sub (by itself with no mains) without any filters in place (no HPF and no LPF)? You are doing some pretty funky stuff with your crossover which is not going to sum well and may be causing your notch (or at least making it worse).

The Revel 105s are ported and have an acoustic 4th order high pass roll off. You are then applying an electrical LR4 @ 60 Hz on top of that effectively making the acoustic high pass behavior 8th order.

Your subs are sealed and you are applying an electrical LR4 @ 60 Hz LPF to them which will not match the 8th order roll off of the Revel 105s. A sealed sub naturally has a 2nd order acoustic roll off but then you apply an electrical BW4 @ 18 Hz HPF making a 6th order acoustic high pass roll off.

Michael

 

[anotherhobby]

Have you tried measuring the sub (by itself with no mains) without any filters in place (no HPF and no LPF)? You are doing some pretty funky stuff with your crossover which is not going to sum well and may be causing your notch (or at least making it worse).

The Revel 105s are ported and have an acoustic 4th order high pass roll off. You are then applying an electrical LR4 @ 60 Hz on top of that effectively making the acoustic high pass behavior 8th order.

Your subs are sealed and you are applying an electrical LR4 @ 60 Hz LPF to them which will not match the 8th order roll off of the Revel 105s. A sealed sub naturally has a 2nd order acoustic roll off but then you apply an electrical BW4 @ 18 Hz HPF making a 6th order acoustic high pass roll off.

Michael

I have measured the subs by themselves. My crossover is at 80 Hz not 60 Hz, and I'm not sure what you mean by "You are doing some pretty funky stuff with your crossover," maybe you could explain what I'm dong that's funky.

As for the notch, it's the layout of my room and subs, and I know specifically what it is. It'll only go away with a 3rd sub. Just not sure if I want to go down that route or not.

 

[mdsimon2]

I have measured the subs by themselves. My crossover is at 80 Hz not 60 Hz, and I'm not sure what you mean by "You are doing some pretty funky stuff with your crossover," maybe you could explain what I'm dong that's funky.

As for the notch, it's the layout of my room and subs, and I know specifically what it is. It'll only go away with a 3rd sub. Just not sure if I want to go down that route or not.

Sorry, you are right I meant 80 Hz, not 60 Hz. And by subs themselves I mean just subs, no mains. I do not means subs and mains together with no crossover. Of course it may still be a room issue and not crossover related.

In terms of "funky" stuff you are applying electrical filters to things that already have acoustic roll offs and not accounting for it in your filter design, therefore you are not ending up with a complementary acoustic crossover. I described this in my previous post but you have an 8th order acoustic high pass on your mains and a 4th order acoustic low pass on your subs. In addition although a 18 Hz HPF on your subs will not change the magnitude response at your crossover point it will certainly change the phase the response of the sub which will effect how the crossover sums.

If you've measured the subs by themselves and you get the same notch then I wouldn't worry about it too much. However you will get better anechoic acoustic summation by modeling the crossover in VituixCAD and accounting for natural acoustic roll offs.

Michael

 

[anotherhobby]

If you've measured the subs by themselves and you get the same notch then I wouldn't worry about it too much. However you will get better anechoic acoustic summation by modeling the crossover in VituixCAD and accounting for natural acoustic roll offs.

Here are the subs on their own with both 24dB/oct LR low pass at 80 Hz and the 24dB/oct BW high pass at 18 Hz.

 

[mdsimon2]

Definitely a room issue and not a crossover issue then.

Michael

 

[vicenzo_del_paris]

Hi,

Received my Flex (unbalanced) today.
It left Hong Kong on Monday evening and has been delivered on Wednesday lunch in Paris, France. DHL did a good job!

Setuping the unit went smooth as expected

But there is a bug the IR learning function (I am using a Logitech harmony hub/remote for automating).
When assigning a command to the different sources (analog, toslink, spdif and usb), it mixes up the assignment.
For example, assigning command 1 to a analog, command 2 to toslink and command 3 to USB: pressing command 3 on generic remote switches the flex to analog instead of USB...
And assigning custom IR commands to sources makes the source selection button of the provided minidsp remote non functional.
I will open a ticket on minidsp support.

 

[Stevienew]

Hello and good evening in this interesting forum! I am new here and would like to introduce myself briefly: My name is Stefan, I am 60 years old and live in Germany. For some time I read along here in the forum and find the most objective approach to the topic "quality of audio products" very good.
My setup looks like this: Lindemann Limetree Bridge as streamer, Nubert nuControl and nuPower d as preamps, power amps drive two Nubert nuVero 14 in my small music room.
In addition, I have a n headphone amplifier Meier audio clasic (without DAC), a Focal Elear and a turntable with preamplifier.
To eliminate the room modes I bought a miniDSP DDRC-24 and I am satisfied with the result.
Now I want to replace the preamp, connect the turntable and streamer to the miniDSP Flex and feed the power amp via outputs 1&2, or feed the HPA via outputs 3&4. Does this work?
Do you have a better idea?

Thanks for your support!

Greetings

 

[Martyreasoner]

Hello and good evening in this interesting forum! I am new here and would like to introduce myself briefly: My name is Stefan, I am 60 years old and live in Germany. For some time I read along here in the forum and find the most objective approach to the topic "quality of audio products" very good.
My setup looks like this: Lindemann Limetree Bridge as streamer, Nubert nuControl and nuPower d as preamps, power amps drive two Nubert nuVero 14 in my small music room.
In addition, I have a n headphone amplifier Meier audio clasic (without DAC), a Focal Elear and a turntable with preamplifier.
To eliminate the room modes I bought a miniDSP DDRC-24 and I am satisfied with the result.
Now I want to replace the preamp, connect the turntable and streamer to the miniDSP Flex and feed the power amp via outputs 1&2, or feed the HPA via outputs 3&4. Does this work?
Do you have a better idea?

Thanks for your support!

Greetings

Yes, it would work for that purpose. You would set the outputs in the routing matrix and then would not use the crossover function.

I assume when you say, "turntable with preamplifier", that you have a turntable with built in phono stage or also have a separate phono stage.

I am confused where in your existing rig you have the DDRC-24. You say, "To eliminate the room modes I bought a miniDSP DDRC-24 and I am satisfied with the result."

 

[Stevienew]

Thanks for your answer! Why are you confused about the DDRC-24?
I wanted to try out DIRAC without spending too much money. The results are ok but the comfort of a DDRC-24 to replace my preamp ist not very good. Therefore, I am considering purchasing another miniDSP that has a display and has the required features.

 

[Martyreasoner]

Thanks for your answer! Why are you confused about the DDRC-24?
I wanted to try out DIRAC without spending too much money. The results are ok but the comfort of a DDRC-24 to replace my preamp ist not very good. Therefore, I am considering purchasing another miniDSP that has a display and has the required features.

I didn't understand where you had the DDRC 24 in your rig. I understand now that you are saying you replaced your preamp with it, I think. And that you are now considering repalcing the DDRC 24 with the Flex. The Flex has the same functionality of the DDRC 24 HD plus a screen, volume knob, coax and bluetooth inputs.

 

[vicenzo_del_paris]

I didn't understand where you had the DDRC 24 in your rig. I understand now that you are saying you replaced your preamp with it, I think. And that you are now considering repalcing the DDRC 24 with the Flex. The Flex has the same functionality of the DDRC 24 HD plus a screen, volume knob, coax and bluetooth inputs.

Same functionality and ... better specs !
The Flex noise is much lower than the DDRC-24. It makes an audible difference when coupled with high gain amplifier and sensitive speakers.
That was my primary reason to upgrade to the Flex.
And when used as a preamp, the front display is valuable

 

[abdo123]

I didn't understand where you had the DDRC 24 in your rig. I understand now that you are saying you replaced your preamp with it, I think. And that you are now considering repalcing the DDRC 24 with the Flex. The Flex has the same functionality of the DDRC 24 HD plus a screen, volume knob, coax and bluetooth inputs.

And the much reduced noise.

 

[Ultrasonic]

I didn't understand where you had the DDRC 24 in your rig. I understand now that you are saying you replaced your preamp with it, I think. And that you are now considering repalcing the DDRC 24 with the Flex. The Flex has the same functionality of the DDRC 24 HD plus a screen, volume knob, coax and bluetooth inputs.

As someone who went from a using a 2x4 HD as a pre-amp to an SHD, the addition of the screen was a HUGE improvement. The Flex now offers this feature for rather less money .

 

[Martyreasoner]

I agree with everyone that the Flex is an improved product.

I own both an 2x4 HD and and SHD. If the Flex existed at the time I bought either the 2x4 HD or SHD, I would have bout the Flex.

 

[Martyreasoner]

My point was that @Stevienew can replace the 2x4 HD to with the Flex without losing any features and would have several added functionalities.

 

[mugbot]

Is there any whiff of a potential Amir review of the flex in the future? I'd love to see how it performs.

 

[anotherhobby]

Is there any whiff of a potential Amir review of the flex in the future? I'd love to see how it performs.

Amir already has a Flex on hand that he said was sent to him for testing by miniDSP. He wasn't sure if it was balanced or not when we exchanged messages, but I'm sure he'll be testing it soon. I'm also sure he still has a backlog from the flooding incident, so I'm not holding my breath.

 

[vicenzo_del_paris]

Got my Dirac licence for the flex
I naively thought that I could upload to the Flex the filters from the Dirac project that I had for my DDRC-24.
Bit Dirac Live app refuses to load previous project when connected to the Flex as the project data embeds device information and detects a device mismatch.
Thus, I need to do the calibration again and apply my target curve.

 

[antcollinet]

Got my Dirac licence for the flex
I naively thought that I could upload to the Flex the filters from the Dirac project that I had for my DDRC-24.
Bit Dirac Live app refuses to load previous project when connected to the Flex as the project data embeds device information and detects a device mismatch.
Thus, I need to do the calibration again and apply my target curve.

I'd contact mini dsp on the forums, and ask if the project can be converted.

 

[Stevienew]

Same functionality and ... better specs !
The Flex noise is much lower than the DDRC-24. It makes an audible difference when coupled with high gain amplifier and sensitive speakers.
That was my primary reason to upgrade to the Flex.
And when used as a preamp, the front display is valuable

I didn't understand where you had the DDRC 24 in your rig. I understand now that you are saying you replaced your preamp with it, I think. And that you are now considering repalcing the DDRC 24 with the Flex. The Flex has the same functionality of the DDRC 24 HD plus a screen, volume knob, coax and bluetooth inputs.

And the much reduced noise.

As someone who went from a using a 2x4 HD as a pre-amp to an SHD, the addition of the screen was a HUGE improvement. The Flex now offers this feature for rather less money .

@all: Thanks for your comments!
Just to clear up the confusion around my chain: Currently the miniDSP DDRC-24 is analog tied in between the preamp and power amp. Volume control and source selection is via my preamp.
The HPA is connected via rec out of the preamp with a fixed level.
My first attempts to replace the preamp with the DDRC-24 failed miserably, as I could not detect level or source.
In addition, it is unusual for me to control the volume for the HPA via the minidsp without a screen.
I expect much more comfort from the miniDSP Flex.

Another consideration is to buy a separate DAC for the headphones and use the HPA separately only for the streamer.

Do you think I will have any sonic losses if I replace the elaborately designed nuControl with such a "little digital box"? My gut feeling still resists a little against this step.