thomann t.racks DSP 4x4 Mini Review

[Propheticus]

This thing is not really comparable. It has 2 in, 8 out. So in a use-case where you want 4 channels in (perhaps already a crossover earlier in the chain and you want to do PEQ/time/phase stuff only), this is not a fit.

Having fixed frequencies makes this a GEQ, not a PEQ, that's how I read the specs. Not comparable if true.

The specs do state it has 3 PEQ per channel
- PARAMETRIC EQUALIZER 3 INDEPENDENT BANDS PER CHANNEL

 

[Severian]

I've been using the larger rackmount t.racks DSP-204 in my system for about two years now. It uses the same software interface, but is based on a 24bit/96KHz DSP. It replaced a Dayton Audio DSP-408, with the primary motivation being balanced I/O given that this is a PC-based system with pro amplifiers that has proven very susceptible to ground loops.

I have been very happy with the unit, except for the fact that I've been unable to get the network connectivity to work and have to use USB to program it. Not a big deal. It's dead quiet and I feel that my sound quality has benefitted from the better gain staging allowed by driving my amps with a 4 volt signal as they are designed for.

 

[mhardy6647]

Why you would need different EQs for old recordings? I am not sure i follow but you can store up to 10 presets if that's helpful.

In any case, I followed the traditional way of setting this up. I spent 2-3 hours in the process of measuring the frequency response of each speaker and tweeking the parametric eq so that i could have a flat frequency response. I haven't tried to do any sort of import of REW files so I'm not sure if that works.

In case you didn't get an answer to this question -- prior to the standardization of the RIAA EQ curve for 33-1/3 rpm "long play" (LP) records, there were multiple "standards" for 78s and even early LPs. In other words, one might say, there were no standards. Many preamps and even some integrated amps (e.g., the redoubtable EICO HF-52) had multiple EQ choices for records up into the early stereo era.
In a similar vein, there are (at least) two not-quite-equivalent EQ standards for reel to reel tape (i.e., NAB and IEC*), and even those curves vary for some different tape speeds.
Ergo, anyone dabbling in (and/or addicted to!) those media might want to be able to experiment with EQ curves for pretty good reason.

\

__________
* I kinda skimmed over the details of this

Los Senderos Studio

A recording studio serving Austin, San Antonio, Blanco, Johnson City, and the Hill Country.

lossenderosstudio.com

 

[PeteL]

Ugh.. I don't mean to be THAT guy.. But..
8 channels or 6 channels about the same price.
Bluetooth control.
Hardware Controls right on the Unit.
Display on unit.
Can turn your amps on as well. (Not sure if it has a time delay etc)


2 channels input instead of 4.
Not balanced.
simple U.I. Vs. Full dashboard.
BYO Power supply.
Most documentation in Spanish/ Portuguese and help/ Forums.

View attachment 202186

Simple video tutorial about it here.

I mean I get this is good for simple setups. But 4 channels? I don't think that cuts it anymore. I'm sure its a great unit. I just don't see the Value here when you can get 8 of them for $119.00 US.

And I'm not sure if this plays out in the real world. But here are the Experts Specs. Seems like this is better way to go if you want more channels. Or do a full active system for a budget with what looks like Better fidelity that works at both home and mobile applications.
View attachment 202196
I bet you some of you electronic wizards could add balanced inputs and outputs to this really is your thing. Maybe an ever better PWM supply inside etc to push it further. Most of you are engineers afterall.

I just think a 4 channel DSP is just not worth it. Even Car head units have 6 outputs with a more limited feature set and about the same sinad I would think.

But again. I'm not the smarty pants here. Just throwing that out there.

I don't doubt that it's a great value. But really I don't get your analysis. Left, right, subs (one or two) (so 3 or 4 channels) is all the vast majority of user will ever need no? What are you gonna be using the other 4 for? It got 2 ins, so it's not like it can be used as a home cinema room correction neither. There are plenty of Surround processor, that is not it, but even if you did want to do that. Just buy too, and in all cases you are closer to be able to use it for that purpose than what you propose. Car audio is different, You have speakers in the back and yo got subs. You need two extra. and the EQ you show IS for car audio, different use case all together.

 

[bennybbbx]

EDIT: when i write only minidsp i mean t.racks minidsp
I have this too and i suggest to use always full level from soundcard into the minidsp and use after the minidsp a monitor controller(a passive is good enough). because a monitor can reach at full level 110 db and more. If you want hear music at 80 db (normal room volume) need reduce soundcard output by 30 db. then you put the 86 db dynamic of the minidsp to 56 db. thats only 9 bit dynamic range and it is hearable in reduced clarity and stereo width

the 7 eq are often a little few but you can use 14 EQ. also in this situation use always full level soundcard output and use later a monitor controller to change volume.

see the matrix setting. you need then connect a symetric cable 3/4 output to the 3/4(in C In D) input. there happen additional A/D convert and D/A convert, but i do compare and did not hear a diffrence. important is of course that the soundcard do always full input. you can depend on matrix setting use 14 eq with additional A/D D/A conversion or 7 eq with not

there are more expense and better t.racks. but they have a fan and thats worse. this mini dsp have no fan and get not warm.

the best sound i get when i put measure microphone of place from left ear and measure left speaker and then place right ear and measure right speaker. averaging with more measure points or measure software give not so good results. i compare with headphone superlux hd 387 which is test here and so i use it as reference and this method sound closest

 

[rvsixer]

Just to make sure we are all on the same track in this thread, t.racks DSP 4x4 mini is not the same as minidsp.

 

[iMickey503]

What are you gonna be using the other 4 for?

Open baffle line array 3 way like this but less stellar. MCM parts, fully active.

 

[Mabob]

I use a Hifiberry DAC+ Pro XLR as source with the t.racks DSP 4x4 mini. The Hifiberry has a 4 volt output signal and according to @amirm review this is sending a clipped signal to the DSP. How does this affect the sound?

Is it possible to lover the output signal from the DAC? Or do I have to change to a DAC with lower output?

 

[bennybbbx]

I use a Hifiberry DAC+ Pro XLR as source with the t.racks DSP 4x4 mini. The Hifiberry has a 4 volt output signal and according to @amirm review this is sending a clipped signal to the DSP. How does this affect the sound?

Is it possible to lover the output signal from the DAC? Or do I have to change to a DAC with lower output?

clipping happen because balanced output have 6db higher signal than unbalanced. seem this dsp is design that it can use full bit dynamic also with unbalanced input. and then with balanced input, level get too high

too high level happen only when you hear too loud. for this dac you need a rasperry as far i understand. and this have a volume setting. maybe you have a digital output display on the rasperry software ?. do you want use a monitor controller after the dsp ?. then you need look that it not go higher as -6 db when use balanced input and play a testtone at 0 db. if you use your soundcard volume to set level then clipping happen only on very loud volume when level go higher as -6 db

 

[Mabob]

clipping happen because balanced output have 6db higher signal than unbalanced. seem this dsp is design that it can use full bit dynamic also with unbalanced input. and then with balanced input, level get too high

too high level happen only when you hear too loud. for this dac you need a rasperry as far i understand. and this have a volume setting. maybe you have a digital output display on the rasperry software ?. do you want use a monitor controller after the dsp ?. then you need look that it not go higher as -6 db when use balanced input and play a testtone at 0 db. if you use your soundcard volume to set level then clipping happen only on very loud volume when level go higher as -6 db

@bennybbbx yes the DAC is on a Rpi4 running Hifiberry OS. I use Spotify as source and the volume is set by it. So far I can't say that I ever noticed any problems even if I it get quite loud sometimes.

I have two PA amplifiers running main speakers and subwoofer. If I understand correctly it's better to set the gain higher on the amplifiers instead of increasing volume too much in Spotify/Hifiberry DAC?

 

[bennybbbx]

@Mabob

you can check if you get distortion with a testtone generator and set volume to 100 % on this page https://www.pckart.net/online-tone-generator/

do a check is also usefull for all sound cards. whewn set in windows 100 and full volume there can happen distortion too

 

[rvsixer]

Is it possible to lover the output signal from the DAC? Or do I have to change to a DAC with lower output?

The 4x4 mini is rated at ~3.1Vrms max input voltage, and does not meet that spec unfortunately and starts clipping at ~2.2Vrms.
If this does indeed become an issue in my own use case, a -5dB inline attenuator should do the trick.

 

[capslock]

does the software support shelving filters? if so, how many per channel?

 

[Mabob]

@Mabob

you can check if you get distortion with a testtone generator and set volume to 100 % on this page https://www.pckart.net/online-tone-generator/

do a check is also usefull for all sound cards. whewn set in windows 100 and full volume there can happen distortion too

@bennybbbx thanks! Will try this.

 

[Mabob]

The 4x4 mini is rated at ~3.1Vrms max input voltage, and does not meet that spec unfortunately and starts clipping at ~2.2Vrms.
If this does indeed become an issue in my own use case, a -5dB inline attenuator should do the trick.

@rvsixer what does a inline attenuator look like? Where can I find one?

 

[Jim Shaw]

Has anyone found a source for this DSP device only (not the amp) in the US? A quick search finds only EU sources.

 

[rvsixer]

Has anyone found a source for this DSP device only (not the amp) in the US? A quick search finds only EU sources.

The device is sourced in China. I ordered from US, device was recieved from EU in about 5 days iirc. No issues.

 

[bennybbbx]

does the software support shelving filters? if so, how many per channel?

you can download the software at thoman page and test the editor. this is called demo mode.

https://www.thomann.de/gb/the_t.racks_dsp_4x4_mini.htm then lower on page are the download. you need download the dsp software and install

click demo to use it without EQ. you can use for every of 7 EQ per channel shelving and Q for shelfing and the low and high pass filters for crossover are additional. it can show phase of EQ. It have very good filters with less group delay so it sound much better as dirac and other for my room when i use for bass and high shelfing filters and do in the range of 100-300 hz no eq. here you can see eq settings with shelving group delay in compare to dirac

How loud is loud, how to measure it? Is THX calibration bad for your health?

It bears repeating this message, if only to save someone else from destroying their hearing. 115 dB peaks in my opinion are about 10 dB too high. It’s cumulative damage. Think of it like new tires on your car. Watching a loud movie is like doing burnouts and donuts. Do enough of them...

www.audiosciencereview.com

 

[Jim Shaw]

The device is sourced in China. I ordered from US, device was recieved from EU in about 5 days iirc. No issues.

Thanks. Like most chintzy bastards, I was hoping for cheaper freight. I'll probably wait until I see the REW results before ordering it. The way things are going, it'll likely be twice the price by then.

What is your experience in using the device? Would it be your choice again?

 

[Smitty2k1]

Considering getting a mic and REW and adding this to my AVR's pre-outs. My Marantz AVR has L/R/Sub pre-out and basic Audyssey with no phone app support. I assume I could keep Audyssey enabled in the AVR and use the AVR for bass management, but then use this for EQ? I don't need balanced (though my amplifier is balanced) but it seems having the 4 inputs instead of just 2 from MiniDSP or Dayton Audio would be a bonus for my setup.