MiniDSP Flex HTx

[terryforsythe]

I'm looking for a multichannel Dirac Live processor with balanced analog connections for my audio post studio. I can't seem to find a used miniDSP DDRC-88A, so this Flex HTx looks like it will fit the bill. Does anyone know if this unit would be an improvement over the DDRC-88A, regarding analog I/O quality and Dirac Live processing?

I assume that the DAC in the Flex HTx is on par with the SHD (second version tested by Amir in the updated review below). I had the SHD and I now have the Flex HTx, and I do not notice a difference in noise level. In fact, with my Flex HTx I cannot hear any noise when putting my ear right next to the tweeter. In contrast, even on my KEF LS60 speakers I can hear a little bit of hiss when I put my ear right next to the tweeter (not audible at 1m, though). I don't know if it is the DAC and/or amplifiers in the KEF LS60 causing the hiss but, in any case, my system with the Flex HTx has a lower noise floor, which is pretty impressive to me.

The DACs in the DDRC-88A do not perform as well as the SHD. The DDRC-88A has a SINAD around 90 - 91 dB, whereas the SHD is around 112 dB. I assume that the Flex HTx is at least on par with the SHD.

Here are Amir's reviews of the DDRC-88A and the SHD:

Minidsp DDRC-88A Dirac Multichannel DSP Review

This is a review and detailed measurements of the Minidsp DDRC-88A balanced 8 channel in, 8 channel out, Dirac and manual EQ DSP system. It is on kind loan from a member and costs US $999. The connectivity as you see is with phoenix connectors and if you order a set of cables to XLR for that...

www.audiosciencereview.com

Minidsp SHD Review Updated (DSP, DAC & Streamer)

This is an update to the review of minidsp SHD that I did a couple of years ago. My tests have evolved since then and company has stated that they fixed a few issues I found in that test. The SHD costs US $1,195 and includes a USB DAC, streaming engine (based on Volumio) and of course, DSP...

www.audiosciencereview.com

 

[citysoundman]

I assume that the DAC in the Flex HTx is on par with the SHD (second version tested by Amir in the updated review below). I had the SHD and I now have the Flex HTx, and I do not notice a difference in noise level. In fact, with my Flex HTx I cannot hear any noise when putting my ear right next to the tweeter. In contrast, even on my KEF LS60 speakers I can hear a little bit of hiss when I put my ear right next to the tweeter (not audible at 1m, though). I don't know if it is the DAC and/or amplifiers in the KEF LS60 causing the hiss but, in any case, my system with the Flex HTx has a lower noise floor, which is pretty impressive to me.

The DACs in the DDRC-88A do not perform as well as the SHD. The DDRC-88A has a SINAD around 90 - 91 dB, whereas the SHD is around 112 dB. I assume that the Flex HTx is at least on par with the SHD.

Here are Amir's reviews of the DDRC-88A and the SHD:

Minidsp DDRC-88A Dirac Multichannel DSP Review

This is a review and detailed measurements of the Minidsp DDRC-88A balanced 8 channel in, 8 channel out, Dirac and manual EQ DSP system. It is on kind loan from a member and costs US $999. The connectivity as you see is with phoenix connectors and if you order a set of cables to XLR for that...

www.audiosciencereview.com

Minidsp SHD Review Updated (DSP, DAC & Streamer)

This is an update to the review of minidsp SHD that I did a couple of years ago. My tests have evolved since then and company has stated that they fixed a few issues I found in that test. The SHD costs US $1,195 and includes a USB DAC, streaming engine (based on Volumio) and of course, DSP...

www.audiosciencereview.com

thank you for your reply and the links!

 

[sarieri]

I assume that the DAC in the Flex HTx is on par with the SHD

Htx uses es9017s. SINAD at 4V is better than SHD, but the multitone is not in good shape at all.
BTW, not sure about 88A, but the Htx does not have input EQ. Only output IIR EQ, which is kinda of limited.

 

[terryforsythe]

Htx uses es9017s. SINAD at 4V is better than SHD, but the multitone is not in good shape at all.

Thanks for the heads up. I found the following thread reviewing the Flex Htx:

MiniDSP Flex HTx Measurement (FW1.1.17 Update)

This is a set of measurements of the Minidsp Flex HTx. It was sent to me by a friend. I have no affiliation to Minidsp. This set of measurements should not be directly compared to Amirm's test as I'm using Comos ADCiso here, but it should provide an general idea of performance of this gear. I'm...

audiosciencereview.com

The following is stated in post #15:

"I described two issues in this thread:
1. Multitone Issue;
2. IMD Issue.

Problem 2 is partially solved (I say partial because I found something new that I’d rather not share at the moment). The ESS Hump is gone for sure. Problem 1 is in investigation hopefully by minidsp.

Now, NONE of the problems I found are likely to be distinguishable double blinded from an objective perspective. Also, even though we have the multitone problem, at reasonable low volume level, this issue is pretty much none existent since the issue I addressed is pretty much gone once the volume is below -15dB. You can check Update2 of Post2 to verify this. I believe to fully fix this multitone problem and the other half of the IMD problem, Minidsp has to do something about the SHARC and maybe matrix router. I still believe there is a correlation between IMD performance and subjective sound quality judgment (but at this low level IMD, maybe not).

With that all being said, this device has no opponent in the market. Short FIXED delay(4.5ms). Top notch SINAD (>120dB). Top notch ADDA (114dB). HDMI input. And it’s only $1k USD. Keep in mind that Topping is selling their DM7 at $600 without so many features. Okto Dac8pro is also more expensive without a fixed delay.

Finally, my measurement is from the perspective of a perfectionist not from a hobbyist. I can’t imagine why someone would complain about the sound quality of this."


EDIT: In post #59 regarding the multi-tone issue and the HTx volume control, it is stated:

"Actually, -10dB is just in terms of absolute safety. Per my measurement, the issue is gone at -6dB. Anything <-6dB should be fine."

I never set my volume up as high as -6dB, so it looks like, at least for me, it is a non-issue.

 

[terryforsythe]

BTW, not sure about 88A, but the Htx does not have input EQ. Only output IIR EQ, which is kinda of limited.

I was aware of that. I researched it before I bought the HTx. If I remember correctly, adding input EQ to the HTx, in addition to the output EQ and all of the other processing the HTx is doing, was going to be too heavy of a load on the processor. I am going from memory and don't remember where I read that, so take it with a grain of salt.

 

[citysoundman]

I assume that the DAC in the Flex HTx is on par with the SHD (second version tested by Amir in the updated review below). I had the SHD and I now have the Flex HTx, and I do not notice a difference in noise level. In fact, with my Flex HTx I cannot hear any noise when putting my ear right next to the tweeter. In contrast, even on my KEF LS60 speakers I can hear a little bit of hiss when I put my ear right next to the tweeter (not audible at 1m, though). I don't know if it is the DAC and/or amplifiers in the KEF LS60 causing the hiss but, in any case, my system with the Flex HTx has a lower noise floor, which is pretty impressive to me.

The DACs in the DDRC-88A do not perform as well as the SHD. The DDRC-88A has a SINAD around 90 - 91 dB, whereas the SHD is around 112 dB. I assume that the Flex HTx is at least on par with the SHD.

Here are Amir's reviews of the DDRC-88A and the SHD:

Minidsp DDRC-88A Dirac Multichannel DSP Review

This is a review and detailed measurements of the Minidsp DDRC-88A balanced 8 channel in, 8 channel out, Dirac and manual EQ DSP system. It is on kind loan from a member and costs US $999. The connectivity as you see is with phoenix connectors and if you order a set of cables to XLR for that...

www.audiosciencereview.com

Minidsp SHD Review Updated (DSP, DAC & Streamer)

This is an update to the review of minidsp SHD that I did a couple of years ago. My tests have evolved since then and company has stated that they fixed a few issues I found in that test. The SHD costs US $1,195 and includes a USB DAC, streaming engine (based on Volumio) and of course, DSP...

www.audiosciencereview.com

I compared the specs and discovered the HTx is lower level compared to the 88A. Max levels are 4V rms compared to 8V rms. The output of my Universal Audio interface is 20dBu max, which is 8V. So I don’t think the HTx is gonna work for me, that’s a bit disappointing.

 

[terryforsythe]

There is way too much confusion being infused into this discussion.

I provided quotes directly from sarieri, who did the testing, that sareri posted in the testing thread. If that information is incorrect, please clarify.

 

[win]

I love the build quality of my okto dac8, but man this makes me kind of wish I saved the money and just got this instead of the ddrc-88d + okto dac8!

 

[Fredygump]

I'm looking for a multichannel Dirac Live processor with balanced analog connections for my audio post studio. I can't seem to find a used miniDSP DDRC-88A, so this Flex HTx looks like it will fit the bill. Does anyone know if this unit would be an improvement over the DDRC-88A, regarding analog I/O quality and Dirac Live processing?

I don't know if you saw this? https://www.audiosciencereview.com/forum/index.php?threads/minidsp-flex-review-audio-dsp.30804/

I guess we don't "actually" know until he tests the HTx specifically, but I purchased with the assumption that the performance would be equivalent to the Flex. And I can say anecdotally that it is much less noisy than my previous processor. I have horn speakers, and my previous processor was giving me unacceptable levels of hissing.

The HTx also has more processing power than the 88A as far as I can tell.

 

[citysoundman]

I don't know if you saw this? https://www.audiosciencereview.com/forum/index.php?threads/minidsp-flex-review-audio-dsp.30804/

I guess we don't "actually" know until he tests the HTx specifically, but I purchased with the assumption that the performance would be equivalent to the Flex. And I can say anecdotally that it is much less noisy than my previous processor. I have horn speakers, and my previous processor was giving me unacceptable levels of hissing.

The HTx also has more processing power than the 88A as far as I can tell.

thanks for the reply. So from whatI'm learning, the Flex HTx is definitely higher quality than the DDRC-88A. But I have a concern regarding levels using the analog IO's of the Flex HTx, and I'd love to get some feedback. I need some help understanding all this! Also, headroom for Dirac Live is something I'm just learning about.

I work as an audio post engineer, and I have a 5.1 system that I want to add Dirac Live room correction. My audio interface is Universal Audio Apollo X6 which has very good DAC's, and max output level is 20dBu. The Apollo is sending to Focal Solo6 BE speakers and Focal Sub. The Focal speakers run at +4dBu. I'm looking for a balanced audio Dirac Live hardware unit to insert between my Apollo interface and Focal speakers.

The Apollo X6 has 20dBu max output, which according to an online calculator, is 8V rms. The Flex HTx max level is 4V rms (equal to 14dBu), while the DDRC-88A is 8V rms which matches the Apollo. So is it a problem to insert the Flex HTX after the Apollo X6 - Does this difference of 4V really matter, considering this is a maximum level? My Focals have a +4dBu input sensitivity, so I'm not sure if this means I'm never operating above +4dBu?? I never listen with my Apollo X6 at anything close to full monitor gain, but I'm not sure what voltage level I'm typically working at.

And to further complicate things, I see that Dirac Live needs 8dB to 10dB of headroom to operate. Does this mean I'd need to be send 8dB lower level to the HTX input to avoid clipping? If so then I'm thinking I'd need to make up this gain. The HTx does have 12dB output gain so that seems like an easy solution.

 

[terryforsythe]

My audio interface is Universal Audio Apollo X6 which has very good DAC's, and max output level is 20dBu. The Apollo is sending to Focal Solo6 BE speakers and Focal Sub. The Focal speakers run at +4dBu. I'm looking for a balanced audio Dirac Live hardware unit to insert between my Apollo interface and Focal speakers.

I don't think the Flex HTx is right for your setup. Since the Audio Apollo X6 has DACs, there should be no need for analog input. Can you feed your Audio Apollo X6 a digital signal? If so, what is type of digital input(s) does your Audio Apollo X6 use?

EDIT: I just looked at a picture of the Audio Apollo X6 back panel. It looks like it has two USB-C connectors. Can you feed digital audio to it via one of the USB-C connectors? If so, maybe run DiracLive on a mini PC or a Mac mini, and output from that to your Audio Apollo X6.

 

[Keith_W]

thanks for the reply. So from whatI'm learning, the Flex HTx is definitely higher quality than the DDRC-88A. But I have a concern regarding levels using the analog IO's of the Flex HTx, and I'd love to get some feedback. I need some help understanding all this! Also, headroom for Dirac Live is something I'm just learning about.

I work as an audio post engineer, and I have a 5.1 system that I want to add Dirac Live room correction. My audio interface is Universal Audio Apollo X6 which has very good DAC's, and max output level is 20dBu. The Apollo is sending to Focal Solo6 BE speakers and Focal Sub. The Focal speakers run at +4dBu. I'm looking for a balanced audio Dirac Live hardware unit to insert between my Apollo interface and Focal speakers.

The Apollo X6 has 20dBu max output, which according to an online calculator, is 8V rms. The Flex HTx max level is 4V rms (equal to 14dBu), while the DDRC-88A is 8V rms which matches the Apollo. So is it a problem to insert the Flex HTX after the Apollo X6 - Does this difference of 4V really matter, considering this is a maximum level? My Focals have a +4dBu input sensitivity, so I'm not sure if this means I'm never operating above +4dBu?? I never listen with my Apollo X6 at anything close to full monitor gain, but I'm not sure what voltage level I'm typically working at.

And to further complicate things, I see that Dirac Live needs 8dB to 10dB of headroom to operate. Does this mean I'd need to be send 8dB lower level to the HTX input to avoid clipping? If so then I'm thinking I'd need to make up this gain. The HTx does have 12dB output gain so that seems like an easy solution.

Are you able to run Dirac on your PC and send the output to your Apollo X6? Then the MiniDSP won't be needed.

 

[citysoundman]

I don't think the Flex HTx is right for your setup. Since the Audio Apollo X6 has DACs, there should be no need for analog input. Can you feed your Audio Apollo X6 a digital signal? If so, what is type of digital input(s) does your Audio Apollo X6 use?

EDIT: I just looked at a picture of the Audio Apollo X6 back panel. It looks like it has two USB-C connectors. Can you feed digital audio to it via one of the USB-C connectors? If so, maybe run DiracLive on a mini PC or a Mac mini, and output from that to your Audio Apollo X6.

The Apollo connects to my Mac via Thunderbolt, using those USB-C connectors. I'm running Pro Tools software which uses the Apollo as the playback engine so it needs the direct Thunderbolt connection. I demo'd the software Dirac Live and it works fine in software but there are work flow inconveniences compared to Dirac in an external hardware unit. For one, I switch between two sets of speakers often when mixing, my Focal as mains and Auratones as small alternate speakers. I'd have to bypass Dirac software every time I switch monitors. Also running Dirac as a plug-in in Pro Tools is fine for listening, but it would have to be bypassed when I bounce a mix master. So a hardware unit with Dirac between the Apollo and speakers is the preferred work flow. The DDRC-88A is used like this in many studios, so I was thinking the Flex HTx would be an upgrade over the DDRC.

 

[citysoundman]

Are you able to run Dirac on your PC and send the output to your Apollo X6? Then the MiniDSP won't be needed.

please see my above reply

 

[terryforsythe]

So a hardware unit with Dirac between the Apollo and speakers is the preferred work flow.

I'm sorry if I missed it, but what is the gain of the amplifier for those speakers?

If the gain is high enough, the 4.0V output of the Flex HTx should be sufficient for that configuration. Just make sure that you have a volume control to keep the output of the Apollo to be no greater than 4.0V.

 

[citysoundman]

I'm sorry if I missed it, but what is the gain of the amplifier for those speakers?

If the gain is high enough, the 4.0V output of the Flex HTx should be sufficient for that configuration. Just make sure that you have a volume control to keep the output of the Apollo to be no greater than 4.0V.

The Focals are +4dBu input sensitivity (equal to 1.228V rms) , which I believe means it can handle up to that level without clipping. So I think it's fine that the HTx outputs 4V max?

My Apollo has a nice desktop volume control - I also have the Apollo Twin MKII desktop interface which is daisy chained via Thunderbolt, this is my monitor controller and talkback.

 

[terryforsythe]

The Focals are +4dBu input sensitivity (equal to 1.228V rms) , which I believe means it can handle up to that level without clipping. So I think it's fine that the HTx outputs 4V max?

Yes, it should be fine. Indeed, I would be surprised if they would not work fine even with unbalanced 2V.

 

[citysoundman]

Yes, it should be fine. Indeed, I would be surprised if they would not work fine even with unbalanced 2V.

Nice, thank you so much for your help!!

 

[Fredygump]

I'm having a problem with eArc and the HTx (possibly?). If my PS5 is turned on, and I switch the TV input to my HTPC, my TV (Sony) screen goes to a black screen saver every 1 min or so. This continues after the PS5 is turned off or disconnected! The PS5 is configured so it doesn't automatically change inputs when it is powered on, and it is set to turn off the PS5 when I turn the TV off. I also changed all my HDMI cables, and then swapped them around with no change. And I don't have any other devices connected via HDMI.

The "fix" right now is to use a tosink output from the TV. The down side is that I lose the "trigger" that turns my amp and the HTx on when I turn the TV on...

Anyone else had a problem with eArc? At first I thought it was the curse of combining a PS5 with a sony TV, but symptoms continue after the PS5 is disconnected...

 

[dweeeeb2]

Its not the pc going into screen saver?