MiniDSP Flex HTx

[sweetchaos]

Source
The table below lists the key input-output specifications of a number of our processors.

	2x4 HD	DDRC‑24	Flex	Flex Eight	Flex HT	SHD	SHD Power	SHD Studio
USB Audio channels	2	2	2	2	8	2	2	2
Analog inputs	2 on RCA	2 on RCA	2 on RCA	–	–	2 on RCA, 2 on XLR	–	–
Analog outputs	4 on RCA	4 on RCA	4 on RCA or TRS (*1)	8 on RCA	8 on RCA	4 on RCA and XLR	2 speaker, 2 RCA	Stereo headphone
Bluetooth input	–	–	Yes	Yes	–	–	–	–
HDMI eARC	–	–	–	–	8ch LPCM	–	–	–
Digital inputs	TOSLINK	TOSLINK	SPDIF, TOSLINK	SPDIF, TOSLINK	SPDIF, TOSLINK	SPDIF, TOSLINK, AES/EBU	SPDIF, TOSLINK, AES/EBU	SPDIF, TOSLINK, AES/EBU
Digital outputs	–	–	(*2)	–	–	SPDIF (4ch)	AES/EBU (4ch)	SPDIF, AES/EBU (4ch)
Dirac Live	Upgradeable	Yes	Upgradeable	Upgradeable	Upgradeable	Yes	Yes	Yes
Dirac Live channels	Stereo	Stereo	Stereo	Stereo	8-channel	Stereo	Stereo	Stereo

Notes:
*1 - Flex has 4 analog output channels on RCA, Flex/balanced has 4 analog output channels on TRS, Flex/Digital has no analog outputs.
*2 - Flex and Flex/Balanced have no digital outputs, Flex/Digital has four digital output channels on SPDIF.

I think this table will be updated to include HTx soon.

 

[AudioJester]

@Keith_W Alternative to deqx?

 

[concorde1]

If I configure DSP on this Flex HTx on Win10 for say L+R + 2 subs, will the unit remember the DSP when computer is running Linux, or does it need software driver running to constantly tell the unit how to do DSP?

I suppose the unit can't be configured on Linux? Unless using something like the unofficial "minidsp-rs" project, which seems to be discontinued.

--

If some way to get working on Linux, I'll probably buy one of these! Looks stellar

 

[himey]

Too bad it doesn't support 16 channel output for decoded Atmos music, considering the connections are all there.

 

[Keith_W]

@Keith_W Alternative to deqx?

Perhaps. I haven't looked at it in detail yet. Does anybody know how many taps it has?

 

[ernestcarl]

Source
The table below lists the key input-output specifications of a number of our processors.

	2x4 HD	DDRC‑24	Flex	Flex Eight	Flex HT	SHD	SHD Power	SHD Studio
USB Audio channels	2	2	2	2	8	2	2	2
Analog inputs	2 on RCA	2 on RCA	2 on RCA	–	–	2 on RCA, 2 on XLR	–	–
Analog outputs	4 on RCA	4 on RCA	4 on RCA or TRS (*1)	8 on RCA	8 on RCA	4 on RCA and XLR	2 speaker, 2 RCA	Stereo headphone
Bluetooth input	–	–	Yes	Yes	–	–	–	–
HDMI eARC	–	–	–	–	8ch LPCM	–	–	–
Digital inputs	TOSLINK	TOSLINK	SPDIF, TOSLINK	SPDIF, TOSLINK	SPDIF, TOSLINK	SPDIF, TOSLINK, AES/EBU	SPDIF, TOSLINK, AES/EBU	SPDIF, TOSLINK, AES/EBU
Digital outputs	–	–	(*2)	–	–	SPDIF (4ch)	AES/EBU (4ch)	SPDIF, AES/EBU (4ch)
Dirac Live	Upgradeable	Yes	Upgradeable	Upgradeable	Upgradeable	Yes	Yes	Yes
Dirac Live channels	Stereo	Stereo	Stereo	Stereo	8-channel	Stereo	Stereo	Stereo

Notes:
*1 - Flex has 4 analog output channels on RCA, Flex/balanced has 4 analog output channels on TRS, Flex/Digital has no analog outputs.
*2 - Flex and Flex/Balanced have no digital outputs, Flex/Digital has four digital output channels on SPDIF.

I think this table will be updated to include HTx soon.

Not all models support loading of manually created FIRs -- including the HT, unfortunately.

 

[RickyC34]

There's not much competition in the multichannel Dac world, this is an exciting product! Topping Dm7 ($600) and Okto Dac8 pro ($1,300?) are the main two that come to mind. At $950 I see the target audience! I currently have Dirac live bass control running on a Mac mini. (2.3 system) One of the major obstacles people have with Dirac via their studio suite (Dirac on your computer) is how they will manage more than two channels. Yes, it is possible to run multiple dacs but on Windows, this can be pretty challenging from my understanding. On Mac, this is supposed to be easier but I'm currently troubleshooting timing issues using multiple DAC's via an aggerate device with drift control.

During troubleshooting, I started looking at dumbing my system down and looked at the available multichannel dacs but I kept coming up with the same problem, they were all balanced only. Is it possible to use balanced and unbalanced outputs at the same time with the Flex HTx? 2.1 of my system is balanced and .2 is unbalanced. Example Bal outputs 1-3 and unbalanced on outputs 4-5.

Any word on what the max sample rate is on this vs usb and HDMI?

The only thing holding previous Minidsp models back from DLBC was the number of inputs I thought? I'm kind of surprised this isn't Minidsp's DLBC coming-out party. Dirac has their black friday sale approaching in just a few days, if this product is capable of DLBC, it would make sense business-wise to release it in time for the holiday. Example Denon 800x series just announcing DLBC.

If I can't get my timing issues fixed with my current setup I will either be picking up a 3800X or this HTx model hoping it can do bal/unbalanced at once and sample over 48Khz.

 

[Keith_W]

During troubleshooting, I started looking at dumbing my system down and looked at the available multichannel dacs but I kept coming up with the same problem, they were all balanced only.

You can easily convert balanced to single ended with a cable or the right adapter.

 

[MAB]

Is it possible to use balanced and unbalanced outputs at the same time with the Flex HTx?

This is possible with the SHD. You can use either RCA or TRS outputs. I assume the HTx will be the same. The HTx manual isn't out yet. MiniDSP customer support seems to be responsive, you might confirm with them.

As Keith_W mentions you can get TRS to RCA adapters, you do need to get the right ones, MiniDSP provides gudiance:

Flex Balanced connectivity: Which TRS to RCA cable should I use?

The Flex balanced is balanced in/out. If you'd like to use an unbalanced amplifier (e.g. Powered subwoofer) downstream of the Flex series, here is the recommended TRS to RCA cable to minimize detrimental effect on the audio quality. Note how...

support.minidsp.com

 

[RickyC34]

@MAB That's promising. Thanks for the info!

 

[dweeeeb2]

I think the manual is out:

miniDSP Flex HTx User Manual

docs.minidsp.com

 

[dweeeeb2]

Perhaps. I haven't looked at it in detail yet. Does anybody know how many taps it has?

Beginner here, how many taps does it need IYO?

 

[IamJF]

Too bad it doesn't support 16 channel output for decoded Atmos music, considering the connections are all there.

It doesn't decode anything! Just use 2 if you need 16 channels ... but you have to decode it before.

 

[Keith_W]

Beginner here, how many taps does it need IYO?

Great question.

Basically, the more taps you have, the greater resolution you can correct at. The calculation is (sampling rate / taps), so if you have a 48kHz sampling rate and you have 1024 taps, you have a resolution of 46.875Hz. To give you an idea of whether this is enough, this is the uncorrected frequency response in my room below 100Hz (brown = left speaker, blue = right speaker):

You can see that in order to correct those peaks and dips, I need a minimum of 10Hz resolution. Preferably 5Hz. I am using Acourate, which allows me to correct to 0.37Hz resolution. This is overkill and I don't think anybody needs to do that, but since I have the capability, I use it. So IMO, 1024 taps per channel is not enough. At 47Hz resolution, you only get two bins to correct the important region below 100Hz, which is clearly not enough. To get 5Hz resolution, you need about 9000 taps per channel. Or you could use a lower sampling rate.

Having said that, my own ears are not good enough to discern the difference between small differences in resolution and amplitude. I do not know what the exact threshold is, and I suspect that it varies between people and how trained your ears are for you to discern such differences. I am not an audio professional, and I think that audio engineers have much better trained ears than I have so they probably have a different opinion to me.

In short, how fine a correction you need to perform depends on your ability to hear such differences and your system's frequency response, which is in turn dictated by your speakers and your room. We are squarely getting into the "can be measured but can not be heard" territory, and how far you want to push beyond the point of diminishing returns depends on you.

You are welcome to pop by my place and I can show you the difference between filters on my system and you can hear for yourself the difference it makes. I can tell you that some of the differences are quite subtle. Just inbox me.

 

[Andysu]

just how many Peq filters does this have , list all the programmable Peq filters

 

[dweeeeb2]

Thanks @Keith_W , I'm going to have to go and process that. I'm having difficulty wrapping my head around the calculation. Sample rate is number of samples per second (48K). If its divided by the number of taps doesn't that mean that each tap is using 46.875 samples? Does this mean tap#1 gets the first 46 samples, tap#2 the second 46 samples or are they distributed differently? See my confusion? I'll go investigate some more, but I get your point. Thank you.

 

[MAB]

just how many Peq filters does this have , list all the programmable Peq filters

They just posted the manual:

Crossover - miniDSP Flex HTx User Manual

docs.minidsp.com

Butterworth (BW)
Available in 6, 12, 18, 24, 30, 36, 42, and 48 dB/octave, Butterworth crossover filters are 3 dB down at the cutoff frequency.

Linkwitz-Riley (LR)
Available in 12, 24, and 48 dB/octave, Linkwitz-Riley crossover filters are 6 dB down at the cutoff frequency.

Bessel
Available in 12 dB/octave only, a Bessel filter gives a more gradual roll-off through the crossover region.

And 10 PEQ filters per channel:

 

[Andysu]

They just posted the manual:

Crossover - miniDSP Flex HTx User Manual

docs.minidsp.com

Butterworth (BW)
Available in 6, 12, 18, 24, 30, 36, 42, and 48 dB/octave, Butterworth crossover filters are 3 dB down at the cutoff frequency.

Linkwitz-Riley (LR)
Available in 12, 24, and 48 dB/octave, Linkwitz-Riley crossover filters are 6 dB down at the cutoff frequency.

Bessel
Available in 12 dB/octave only, a Bessel filter gives a more gradual roll-off through the crossover region.

And 10 PEQ filters per channel:
View attachment 326554

thank you , 10 peq , not enough , to cover what i would need 20,200 Peq band filters to do proper thank you

 

[ernestcarl]

It doesn't decode anything! Just use 2 if you need 16 channels ... but you have to decode it before.

But how would that work with the HDMI input?

I’d rather get a QSC processor etc.

thank you , 10 peq , not enough , to cover what i would need 20,200 Peq band filters to do proper thank you

You probably mean the graphical EQ points type?

Total max biquads available I think is 28. Divided between the input and output stages. Eight extra from the crossover section if you use manual mode.

 

[3ll3d00d]

If its divided by the number of taps doesn't that mean that each tap is using 46.875 samples?

No, https://www.minidsp.com/images/documents/fir_filter_for_audio_practitioners.pdf seems a reasonable summary / introduction which may help