Ummm.. Yeah. MiniDSP. Live Sound

[CountMackula]

Ive been looking at MiniDSP. Im pretty sure you all have heard of it (thanks for reviewing the 2x4 HD and SHD)

Im a noob. Annually I use our PA equipment to “run sound” for a local dance studio’s recital. Probably for over 15 years. Skipping the history, current setup I use is:
Laptop with music. Who knows what format they were in originally but the director gives them to me in mp3 usually and normalizes them.

To avoid having to raise and lower volumes during the shows, I usually drop them into PreSonus StudioOne 3 Pro and re mixdown the songs individually with compressor and my ears on my Mackie HR824s to achieve more consistent volume levels. Im sure readers here are already cringing.. believe me the quality of these tracks can be.. rough, to state politely.

Historically I ran headphone jack to RCA into an Allen and Heath mixer (most years i have to provide wireless microphones for a few singers) but beginning last year we have adde a Behringer X-Air 18 to our setup. This outputs via long XLRs to a rack mount crossover (thats old with dirty pots and i hate it)

Tip ring sleeve 1/4” cables then go to our QSC 2450s that each run our mains and a QSC 5050 that runs one or two 18” subs.

So, a couple of questions and ponderings. I’d be curious how you'd test the Behringer X-Air18 for quality and the results.

I’ve read comments that the 2x4 and 2x4 HD can have noise issues. Keeping in mind that im often playing back mp3s through a bunch of cable types running through multiple equipments and the audiences and directors are already content with the quality. What sort of noise and artifacts are people talking about?

I’d considered the 2x4 balanced and even the SHD because of balanced outputs to hopefully avoid “line noise”. Are these deficiencies people talk about here only cringeworthy for audiophiles and due to the fact that the source material is just mp3 quality it wouldnt matter or are we talking some serious noise/artifacts to the untrained ears of parents who arent really there to focus on music quailty but instead their daughter dancing? What do you feel would be the advantage to balanced cables or do you feel a 2x4HD would work in a live sound application like ours.

I’d also want to use this with bands potentially and definitely as a general replacement for the rackmount crossover.

Would i need a 50’ - 100’ USB cable to take a laptop out in an auditorum to get UMiK locations?

I can’t find a ton of people using MiniDSPs for their PA systems for some reason. Any thoughts at all to this?

My main goals are to replace the crossover, get room correction (probably dirac, REW may be a lot for me by May) and generally reduce the amount of equipment needed and streamline the room measuring process to “quickly”. My UMik arrives Friday.

Even if you dont have an opinion on my setups perhaps some people might recommend some easier way to play back the music. I am converting the mp3s back to WAV so anything that could play WAV i could use.

 

[RayDunzl]

Looking at the measurements of it and your intended usage, I don't see where it would be a problem.

I have a 2x4 HD.

It controls four subs at the moment.

I've used it on the main speakers and don't remember noticing anything unusual. Soon afterwards reconfigured and returned to the main DAC.

Id considered the 2x4 balanced and even the SHD because if balanced outputs to hopefully avoid “line noise”.

If the cable legth is short and the voltage levels on the unbalanced outputs are appropriate for the amplifier inputs, you may or may not pick up noise that would pass by a balanced connection. Try it and see what happens.

Would i need a 50’ - 100’ USB cable to take a laptop out in an auditorum to get UMiK locations?

That distance is beyond the reach of a passive USB cable. You'd need a cable with repeaters:

Example: https://www.amazon.com/TRIPP-Hi-Spe...UTF8&qid=1549518764&sr=8-10&keywords=50ft+usb

I cant find a ton of people using MiniDSPs for their PA systems for some reason. Any thoughts at all to this?

They aren't the intended audience.

 

[CountMackula]

Thanks for some real feedback.

Im suddenly overwhelmed on these sites and reviews reading about these DACs. Topping D10, D30, D50. SMSL SU-8. Would these be worth the investment? Would it be beneficial to go USB from my laptop to an SMSL SU-8 for Digital to Analog, then XLR to my X-Air Mixer (only needed to allow 2 microphones in the mix) then I’d XLR L-R out to RCA to go into a 2x4 HD (this has another DAC yes? That would be double processing and maybe bad or redundant?) then i’d have to convert back to 1/4” or XLR to go into the power amps.

So I guess your response means I would need to USB from the laptop to the 2x4 HD connected to the amps to do Dirac/REW analysis. Correct me if i misinterpretted that and thanks for the link to the long USB repeater.

Can you actually play music USB into the 2x4 HD? Like could I have my mixer with 2 mics go to the analog RCAs on a 2x4 HD while simultaneously playing WAVs in foobar 2000 via USB?

Im willing to pony up for some more expensive gear if it simplifies my setup i just dont want to buy stuff to figure it out and have to return it if its not the right fit because i travel M-F and im terrible about returning stuff when im home on the weekends.

I really want to use the minidsp as a crossover and get the room correction down to a quicker process. The last two years ive used this plugin (https://mathaudio.com/room-eq.htm) to foobar 2000 for room correction and i believed it was good but i didnt have the UMIK that comes in this week.

Thanks for taking time to answer my uneducated questions for something that probably isn't a typical application in this forum and possibly uninteresting to you all.

 

[andreasmaaan]

Im suddenly overwhelmed on these sites and reviews reading about these DACs. Topping D10, D30, D50. SMSL SU-8. Would these be worth the investment? Would it be beneficial to go USB from my laptop to an SMSL SU-8 for Digital to Analog, then XLR to my X-Air Mixer (only needed to allow 2 microphones in the mix) then I’d XLR L-R out to RCA to go into a 2x4 HD (this has another DAC yes? That would be double processing and maybe bad or redundant?) then i’d have to convert back to 1/4” or XLR to go into the power amps.

Given your source material, equipment chain, and the fact that (I presume) the room is not acoustically optimised, etc., I wouldn't spend a lot of money on the DAC stage of your system. Even many of the cheaper (under $100) DACs these days have low enough noise and distortion that they are audibly indistinguishable from each other or anything more expensive, even using excellent speakers in properly set-up listening rooms.

If you have some money to spend on this system, consider room treatment or a speaker upgrade (ofc I don't know what you're currently using). The law of diminishing returns with DACs kicks in at about $10 or $20.

Nor would I worry about double-processing. However, I'd put the money and effort into treating the room (if possible), upgrading speakers/subs, and convincing the director to provide better quality source material.

In your position I would certainly stick to an all-balanced signal chain though. Perhaps the kind of processing you want to do can be done at the source, on the laptop?

FWIW though, which speakers are you using?

 

[CountMackula]

The venues are usually public school auditoriums so id say adding room treatment is off the table. Most appear to have some sort of i assume bass traps on the walls, or some sort of acoustic paneling for sound wave control. They’re old schools but designed for acoustics at some raw level i assume.

The Speakers I believe are Madison brand. The mains i believe have dual 15” black widow woofers and a horn. Theyre pretty old and i cant recall without looking. The sub(s) were two single 18” also Madison brand. Though one blew out and it’s replaced with who knows what 18”. So usually ive just been bringing one sub. It’s usually enough.

We’ve considered replacing them but they get the job done for this particular customer and the few bands we reinforce.

The foobar room correction plugin seemed to make them sound pretty solid.

One year I had someone stand in the audience with a radio shack SPL meter and I played 32 test tones from a minirator at the frequencies for my old 32 band EQ and then adjusted the EQ some based on the SPLs and it sounded pretty good that time too.

Im more concerned to get rid of the rack crossover we have and be able to do a quick room correction measurement in about 30 minutes. There are usually a lot of kids and parents around while im setting up so the REW type sweep sound is quick instead of me having annoying long test tones playing.

 

[andreasmaaan]

The venues are usually public school auditoriums so id say adding room treatment is off the table. Most appear to have some sort of i assume bass traps on the walls, or some sort of acoustic paneling for sound wave control. They’re old schools but designed for acoustics at some raw level i assume.

The Speakers I believe are Madison brand. The mains i believe have dual 15” black widow woofers and a horn. Theyre pretty old and i cant recall without looking. The sub(s) were two single 18” also Madison brand. Though one blew out and it’s replaced with who knows what 18”. So usually ive just been bringing one sub. It’s usually enough.

We’ve considered replacing them but they get the job done for this particular customer and the few bands we reinforce.

The foobar room correction plugin seemed to make them sound pretty solid.

One year I had someone stand in the audience with a radio shack SPL meter and I played 32 test tones from a minirator at the frequencies for my old 32 band EQ and then adjusted the EQ some based on the SPLs and it sounded pretty good that time too.

Im more concerned to get rid of the rack crossover we have and be able to do a quick room correction measurement in about 30 minutes. There are usually a lot of kids and parents around while im setting up so the REW type sweep sound is quick instead of me having annoying long test tones playing.

Ok that makes sense

I would definitely invest in a USB measurement mic (the models from both Dayton and MiniDSP are excellent and inexpensive) and use that to take sweeps.

Based on the speaker system, what I said above re: spending money on an expensive DAC or DSP unit still stands - I just don't think in the kinds of spaces you set this system up there will be any audible difference whatsoever between a state-of-the-art DAC and very cheap DAC (unless there's something seriously wrong with it).

In terms of implementing EQ and sub crossovers with DSP, you might want to look at MiniDSP 2x4 Balanced. To my knowledge, this device uses an ADAU1701 processor which has an SNR of about 100dB and THD+N of about -80dB. That should be more than adequate audio performance for your needs. It can be purchased in a bundle with the MiniDSP USB mic and power supply for US$200.

This unit does not have DIRAC or any other automated room correction, but if your goal is simply to run sweeps using the mic and then fix some crossover and EQ settings manually, this can be done quickly via USB to the 2x4.

If you want to also use DSP to manually fix internal crossovers in the speakers, you'll obviously need more than 4 channels. It would be possible to run two of these units, one for each side. I believe it may also be possible to link two of these in a master/slave clock arrangement, but I'm not sure. The units are supposed to have fixed latency in any case, so syncing the clocks probably isn't strictly necessary for the non-critical listening environment you're running the system in.

EDIT: there is an 8-channel balanced version available anyway. Would require you put it in some kind of housing.

 

[CountMackula]

My miniDSP umik arrives tomorrow. I ordered it off amazon before i saw you could get it as an addon from minidsp.

The 2x4 balanced is one i was looking at indeed. Though it isnt offered in the “HD” version so I wasnt sure what I was maybe missing there if anything or if figuring out a way to use the RCAs to use the 2x4 HD was worth it somehow.

Originally I was planning to do REW but the dirac does have some appeal to me. I work A LOT and dont seem to find as much free time these days. Plus spending time with the wife when im home and she is off is priority so these days im like maybe less patient to sit down with REW. Last time I tried it was a bit of a challenge, though i didnt have a UMIK then so i was working with a Presonus audiobox USB with an XLR mic and dealing with ASIO drivers and all kinda shtuff so my brief attempt back then has Dirac sounding a bit nicer right about now. The MiniDSP SHD i have been eyeing for that reason haha that and it has XLR in and 4 XLR outs. It also has streaming over ethernet so i could potentially put it in a power amp rack then run an ethernet to my listening position as im not sure if you can stream over the optional wifi adapter or if that is strictly for controlling the MiniDSPs settings. Im not even sure much about the MiniDSP tbh. I did look in the PDF manuals though.

But the price tag on the 2x4 balanced is Quite nice so it would be a good starter kit that I could convert to something else later whereas the SHD is sort or All In.

As for the DACs, thanks for the feedback there. I mean, the comments so far say not to go for expensive and state of the art DAC.. however im not sure what everyone here considers expensive and state of the art. That Topping D10 i think is like $100 or less and someone said it sounds very nice. Even that SMSL SU-8 ive been reading sounds nice and it has XLR outs so id be willing to go up to the $200-$250 range for that if it’s worth it but thats probably about as high as Id want to spend on something like that but it sounds like youre saying even the D10 would be a waste of money for my application but i definitely throw down a hundo for it if you think it would be noticably nicer sounding to me.

I’d love to ditch my mixer and laptop all together if I could and drop down to just a miniDSP and something that allows two 1/4” or XLR but I gotta feed two wireless mics in somehow and have some control on their levels.

Also I run two stage monitors separately so id considered that 2x8 you mentioned as well if I could separate them with their own EQ/corrections for managing stage feedback (usually rolling off bass freqs seems to help control that though)

Also as mentioned earlier I wasnt planning to replace my speakers but we have looked at potentially replacing them so Im open to suggestions on PA speakers but Im not sure thats really for this thread haha

Thanks again for all your replies. This is helpful for me to talk these things out with you all. Really do appreciate your time.

 

[andreasmaaan]

As for the DACs, thanks for the feedback there. I mean, the comments so far say not to go for expensive and state of the art DAC.. however im not sure what everyone here considers expensive and state of the art. That Topping D10 i think is like $100 or less and someone said it sounds very nice. Even that SMSL SU-8 ive been reading sounds nice and it has XLR outs so id be willing to go up to the $200-$250 range for that if it’s worth it but thats probably about as high as Id want to spend on something like that but it sounds like youre saying even the D10 would be a waste of money for my application but i definitely throw down a hundo for it if you think it would be noticably nicer sounding to me.

See above. In the environment you're working in, there is really no point spending any significant money on a DAC.

In terms of what people here consider expensive or SOTA, I obviously can't speak for everyone, but in general Amir's testing shows that just a shade below SOTA performance can be had for as little as $100. I think many here would agree that you're already in the range of no audible difference with some devices that cost below $100.

The MiniDSP units (even the bottom of the range ones) have THD+N in the -80dB range. Have you tried hearing something 80dB below the signal? There have been some people under some conditions who've managed to discern a difference between -90dB added distortion and no added distortion on some music signals. But only with practice and only in good conditions. It's extremely difficult even in a quiet room with state-of-the-art speakers. In your situation, there's just no way IMHO there will be any audible difference between -80dB and -100dB (e.g. Topping D10, numerous DACs costing upward of $1k, etc).

Spending some money on speakers will however make a very audible difference (assuming you're not 100% happy with what you have). The differences between speakers are exponentially greater than the differences between DACs. Focus on that, if anything. That's my 2c anyway

 

[bigx5murf]

Don't many of the Crown live sound amps have DSP built in? Some even have a USB port so you can use a laptop to tune the DSP.

 

[CountMackula]

@bigsmurf We have looked at new amps with DSPs and crossovers. Most of the new ones are much lighter as well.

Not sure any of them have REW / Dirac capabilities but i havent looked in a while

 

[CountMackula]

See above. In the environment you're working in, there is really no point spending any significant money on a DAC.

this is confusing me, define significant,.. like $250? $1000? Or like literally any money? $100 D10 together with a $139 MiniDSP 2x4 balanced doesnt really sound significant to me, but it may be unnecessary.. which is what I think you're tellin me

In terms of what people here consider expensive or SOTA, I obviously can't speak for everyone, but in general Amir's testing shows that just a shade below SOTA performance can be had for as little as $100. I think many here would agree that you're already in the range of no audible difference with some devices that cost below $100.

So buying a DAC $100 or less would be a good idea? because this part sounds like “buy a DAC but keep it below $100”. Amir’s MiniDSP reviews is how I found this place. im happy i did and id be interested to hear his take too and anyone who likes talking about this stuff in addition to you, thanks for the comments. At this point if i did buy a DAC i think id be comfortable with the D10 even though i was reading good stuff about the D30 and D50 etc.) The SU-8 was mainly in the equation because of XLR and the reviews here sounded good as well, but sounds like a DAC i probably dont really need right now

The MiniDSP units (even the bottom of the range ones) have THD+N in the -80dB range. Have you tried hearing something 80dB below the signal? There have been some people under some conditions who've managed to discern a difference between -90dB added distortion and no added distortion on some music signals. But only with practice and only in good conditions. It's extremely difficult even in a quiet room with state-of-the-art speakers. In your situation, there's just no way IMHO there will be any audible difference between -80dB and -100dB (e.g. Topping D10, numerous DACs costing upward of $1k, etc).

This sounds like “just buy a MiniDSP because the difference between its quality and one of the DACs is small so no need to spend for a DAC before the MiniDSP”

Spending some money on speakers will however make a very audible difference (assuming you're not 100% happy with what you have). The differences between speakers are exponentially greater than the differences between DACs. Focus on that, if anything. That's my 2c anyway

Yeah, kinda focused on this electronics stuff at the moment because it’s a lot to take in so quickly, this DAC stuff is like a whole ‘nother world I just got tossed into, wow! so it would maybe be overload to start researching speakers. I don't know about “100% happy” but they're a’ight. I’m not losing any sleep over them. Probably “comfortable” with them is a good way to put it. Been using them probably 10-15 years. I’d be open to hearing speaker recommendations though for sure if you all have some you like though, but when i start looking for myself i start looking at stuff i cant afford like Martin arrays and then i give up haha

Appreciate the replies, i think youre telling me not to spend any money on a DAC for my application so unless I hear some compelling counter arguments ill probably just keep focusing on the MiniDSP part.. which mainly Im a bit torn on:

Balanced vs unbalanced
Dirac or REW

Still trying to understand a bit about the MiniDSP setup and whether i would be using USB or analogs for playback

 

[andreasmaaan]

this is confusing me, define significant,.. like $250? $1000? Or like literally any money? $100 D10 together with a $139 MiniDSP 2x4 balanced doesnt really sound significant to me, but it may be unnecessary.. which is what I think you're tellin me

The MiniDSP 2x4 doesn't have digital output, so you can't use it with external DACs. So here I'm saying it's not really worth spending a lot of a top shelf-DSP with inbuilt DACs, e.g. the MiniDSP Studio (unless you want to use DIRAC).

I do generally think it's worth spending $100 on a DAC for home audio (but not more unless for specific features, i.e. not more for sound quality). I don't think it's worth spending that much for use in large sub-optimal spaces like you intend to use yours.

This sounds like “just buy a MiniDSP because the difference between its quality and one of the DACs is small so no need to spend for a DAC before the MiniDSP”

Ah now I see what you're talking about! You're thinking of putting a DAC between the laptop and the miniDSP. I had been thinking you wanted to output from something like the MiniDSP to separate DACs. Ok, that makes some sense (although I suspect it again won't make much of a difference). Which laptop do you have? Most laptops have pretty good audio performance these days.

Appreciate the replies, i think youre telling me not to spend any money on a DAC for my application so unless I hear some compelling counter arguments ill probably just keep focusing on the MiniDSP part.

Yeh this is exactly what I'm saying

Balanced vs unbalanced

I wouldn't even think about going unbalanced if I were you. You'll be in all sorts of different electrical environments, there will be long cable runs, you won't have time to troubleshoot groundloop and noise issues, etc. There's good reason balanced is standard for PA.

Dirac or REW

A question of your personal preference mostly. I've always done this kind of thing myself using measurements because I like to have full control. But I've never used DIRAC so can't really speak to it. Not sure how well it would work outside the home/studio context for which (IIUC) it was designed.

Still trying to understand a bit about the MiniDSP setup and whether i would be using USB or analogs for playback

The 2x4 only accepts analogue input. The USB input is there only so you can adjust the filters and crossover points etc. All audio must go in through the analogue inputs. There are other MiniDSP models and other DSP/Xover devices in general that allow for digital input though.

 

[andreasmaaan]

@bigsmurf We have looked at new amps with DSPs and crossovers. Most of the new ones are much lighter as well.

Not sure any of them have REW / Dirac capabilities but i havent looked in a while

I believe REW is a piece of measurement software only. It can't be used to control a DSP (to my knowledge). Sp you'd need to take measurements in REW and then use whatever software/hardware you have to set the filters, EQ, etc.

@bigx5murf is right though, many of the Crown amps have built in DSP and this would do the job just as well as e.g. MiniDSP 2x4.

 

[CountMackula]

I believe REW is a piece of measurement software only. It can't be used to control a DSP (to my knowledge). Sp you'd need to take measurements in REW and then use whatever software/hardware you have to set the filters, EQ, etc.

@bigx5murf is right though, many of the Crown amps have built in DSP and this would do the job just as well as e.g. MiniDSP 2x4.

Cool. i thought you could create a filter file in REW and just upload it to the MiniDSP and I guess I thought that was the whole reason everyone liked the MiniDSP was because you could import config/filter files from REW exports or something. Will have to check out some crown amps again maybe in the future

 

[andreasmaaan]

Cool. i thought you could create a filter file in REW and just upload it to the MiniDSP and I guess I thought that was the whole reason everyone liked the MiniDSP was because you could import config/filter files from REW exports or something.

That's very possible

 

[CountMackula]

The MiniDSP 2x4 doesn't have digital output, so you can't use it with external DACs. So here I'm saying it's not really worth spending a lot of a top shelf-DSP with inbuilt DACs, e.g. the MiniDSP Studio (unless you want to use DIRAC).

I do generally think it's worth spending $100 on a DAC for home audio (but not more unless for specific features, i.e. not more for sound quality). I don't think it's worth spending that much for use in large sub-optimal spaces like you intend to use yours.



Ah now I see what you're talking about! You're thinking of putting a DAC between the laptop and the miniDSP. I had been thinking you wanted to output from something like the MiniDSP to separate DACs. Ok, that makes some sense (although I suspect it again won't make much of a difference). Which laptop do you have? Most laptops have pretty good audio performance these days.



Yeh this is exactly what I'm saying



I wouldn't even think about going unbalanced if I were you. You'll be in all sorts of different electrical environments, there will be long cable runs, you won't have time to troubleshoot groundloop and noise issues, etc. There's good reason balanced is standard for PA.



A question of your personal preference mostly. I've always done this kind of thing myself using measurements because I like to have full control. But I've never used DIRAC so can't really speak to it. Not sure how well it would work outside the home/studio context for which (IIUC) it was designed.



The 2x4 only accepts analogue input. The USB input is there only so you can adjust the filters and crossover points etc. All audio must go in through the analogue inputs. There are other MiniDSP models and other DSP/Xover devices in general that allow for digital input though.

So, this i think was maybe why people were suggesting the 2x4 HD over the regular 2x4?

Unfortunately, they dont offer the HD in balanced.

You have to go up to some $899 model and at that price i might as well get the SHD at 1200

I guess the REW and MiniDSP relationship is still a bit foggy for me as well. But.. i think maybe I was thinking Id somehow have the MiniDSP hooked to my amps which are connected to my speakers, then hook the laptop into it for playback and then put the USB UMIK into the laptop to record the sweep from REW (confusion here on whether it would be USB playback?) or maybe i have to run analogs out the laptop to the MiniDSP to get playback and then put the UMIK into the laptop? Or do I run really long analog cables from the amps out to the audience seating plugged from MiniDSP outs, with the UMIK in the USB for MiniDSP and Laptop analog in with REW.. my brain is about to explode haha

 

[andreasmaaan]

So, this i think was maybe why people were suggesting the 2x4 HD over the regular 2x4?

Unfortunately, they dont offer the HD in balanced.

You have to go up to some $899 model and at that price i might as well get the SHD at 1200

I guess the REW and MiniDSP relationship is still a bit foggy for me as well. But.. i think maybe I was thinking Id somehow have the MiniDSP hooked to my amps which are connected to my speakers, then hook the laptop into it for playback and then put the USB UMIK into the laptop to record the sweep from REW (confusion here on whether it would be USB playback?) or maybe i have to run analogs out the laptop to the MiniDSP to get playback and then put the UMIK into the laptop? Or do I run really long analog cables from the amps out to the audience seating plugged from MiniDSP outs, with the UMIK in the USB for MiniDSP and Laptop analog in with REW.. my brain is about to explode haha

Yeh it gets difficult in a large space like that. Not sure what the best solution is here.

Also keep in mind that to do the correction you'll need to run a lot of sweeps from a variety of different locations in the venue.

 

[CountMackula]

BTW, i found a teardown of the mixer we use. Maybe someone here would recognize some of the chips in it? I think I did USB playback in it before so im guessing it has a DAC

http://vogelchr.blogspot.com/2015/11/behringer-x-air-xr18-teardown.html?m=1

 

[andreasmaaan]

BTW, i found a teardown of the mixer we use. Maybe someone here would recognize some of the chips in it? I think I did USB playback in it before so im guessing it has a DAC

http://vogelchr.blogspot.com/2015/11/behringer-x-air-xr18-teardown.html?m=1

It's actually a digital mixer. So all analogue inputs are converted to digital, processed internally, then converted back to analogue. This is pretty standard though, and definitely a good thing.

And yes it can also do USB audio.

 

[CountMackula]

Yeh it gets difficult in a large space like that. Not sure what the best solution is here.

Also keep in mind that to do the correction you'll need to run a lot of sweeps from a variety of different locations in the venue.

Last year I ran a 100’ XLR from the X Air mixer you just saw out to maybe 5 spots in the crowd and did sound samples to that mathaudio plugin i linked up above. Im looking to do the same thing but maybe use REW or Dirac to measure the room with the UMIK to get room correction curves