Behringer Studio XL Monitor Controller

[Sokel]

Did a little test for the "what if" and zapped the XLR (mic) input of the E-MU with 2V (0dB analog input) just to see.
Don't know if it's applicable to the above but here it is (THD alone plus THD+N on the chart) :



It does take a hit at 2.1V but not much.

(it's also a dead cheap and very old interface, so no excuse for Behri)

 

[Geert]

As I said above, this behaviour is what they proudly call "Midas signature" preamp. It's done on purpose, not by accident.

The same distortion behaviour is seen on the USB input, no preamp involved. It's about levels and clipping, as show in the measured waveform. Midas preamps don't clip under normal use.

 

[Rja4000]

The same distortion behaviour is seen on the USB input, no preamp involved. It's about levels and clipping, as show in the measured waveform. Midas preamps don't clip under normal use.

The DAC part is a completely different story.

 

[boxerfan88]

Is that why there is the +/-12dB trim on their line inputs 3-6?

 

[sergeauckland]

Why? What products do they get right?

Their Compressor/limiters are fine, we have two working 24/7 for the past 15 years at our local FM station. Ditto their DI boxes, used as unbalanced-balanced converters, I installed about 12 of these and all still working fine. I have their DCX, DEQ and A500 amps working for over 15 years at home, several Behringer microphones and mixers again all working well for over 15 years. Their USB interfaces are less successful. As with this product, they have their minimum distortion well down, such that by anywhere near 0dBFS it's far too high, both on the DAC side, which isn't great, but worse on the ADC side. Surprisingly, their stupidly cheap UCA202 works well. Have several of those, but input and output levels are consumer, not Pro.

Oh, and their cable tester is a really useful tool.

Something of a mixed bag, but for some reason, their ADC/DAC USB interfaces seem universally poor, with the exception of the UCA202. They can get ADCs and DACs right, as those in the DCX and DEQ products are OK. Not SOTA by any means, but still perfectly Good Enough for transparency.

S.

 

[andymcbain]

Those things are mostly used as an analog monitor controller between the interface and monitors. Digital connections are just a bonus and there are a lot of similar devices without it.

Yes - they needn’t have bothered with the converters in my opinion. All I’d be looking for in a monitor controller is plenty of analogue I/O, good routing options, decent pots and transparent analogue circuitry - In a small table top format. Affordable boxes like that are few and far between.

 

[Geert]

The DAC part is a completely different story.

We need to consider them separately indeed, but when they show the same distortion spectrum then there's a common root cause. Being the circuit following the inputs.

 

[boxerfan88]

Looks like their THD+N is specced at -80dB @ 1kHz @ unity gain @ 4dBu input.

 

[Geert]

Their Compressor/limiters are fine, we have two working 24/7 for the past 15 years at our local FM station.

Their compressors were widely used in the pro audio world, combined with analog mixing consoles that cost fortunes.

 

[Lambda]

If they want to add that kind of effect, why not.
But then they should document it properly and make it defeatable.

Well they tell you to set the gain according to the meter. if you do so you don’t get saturation.
But unlike with some other interface if you go over 0dB you get "soft" saturation and not had clipping.

in many ways this Graceful slow degradation is (if you don't set the gain right) is better (for live recording) then hard clipping.

 

[Rja4000]

Well they tell you to set the gain according to the meter. if you do so you don’t get saturation.

And then you loose 20dB of dynamic range ?

But unlike with some other interface if you go over 0dB you get "soft" saturation and not had clipping.

Define "soft".
With the look of the sine wave, it's nothing like "soft"

in many ways this Graceful slow degradation is (if you don't set the gain right) is better (for live recording) then hard clipping.

I really don't see why.
You're loosing on both sides: dynamic range and distortion.

 

[Herbert Shooler]

Anyone heard of the "The Audio Analyst"??? This guys capacity for conceit,self deceit and delusion sets new standards in audio....

 

[solderdude]

What's 'the audio analyst' got to do with this Behringer device ?

 

[amirm]

The DAW software output is usually well below 0dBFS. most have 18 or 20dB "headroom"

Now this has become part of an editing chain? No one is going to play commercial music through it with loudness compression? Or make the same?

 

[amirm]

Well the Company documented this and the Company build the req

There is zero documentation to avoid approaching 0 dBFs or distortion skyrockets.

 

[amirm]

Well the Company documented this and the Company build the required metering right in... you just chose to ignore it.

You are confused. As I have said repeatedly, it doesn't matter what analog level you set. If input is near 0 dBFs, you get severe distortion.

 

[amirm]

And all I'm saying is that the maximum analog output (or internal bus) level corresponds to 0 dB FS on the USB input. So when you target the nominal output level of 4dBu, you shouldn't drive the USB input to 0dB FS.

If I am playing some music through it, I have no control over the PCM samples. This thing will saturate not only at 0 dBFS, but even at -1 dBFS:

If all was well here, you could sort of hang your hat on this. But per above, performance is still horrible. This would not be acceptable in a $5 Aliexpress DAC. But we are supposed to accept it for a "professional" tool? We are talking distortion floor that is whopping 40 dB higher than CD spec below 0dBFS! And again, remember, clipping behavior happens regardless of what you set the analog voltage level to.

Meanwhile people want me to go above 0 dBFS and test for "intersample overs."

When something is broken this way, we need to point it out so it is fixed. Zero benefit comes to any consumer for this type of overflow. It has no reason to exist. Literally hundreds of DACs I have tested pass this with flying colors regardless of price. Had there been a proper set of measurements used to verify the design, it would have been caught and fixed (hopefully).

So let's not attempt to paper over this. Company needs to be motivated to fix problems like this. It would have been a wonderful device and incredible value if it hadn't had such serious problems in its design.

 

[amirm]

You're putting words in my mouth. The only thing I said about the broadcast world is that they are strict about nominal levels.

They are also extremely strict in not allowing products like this in that fail the basic test of near/at 0 dBFS output.

 

[Lambda]

Now this has become part of an editing chain? No one is going to play commercial music through it with loudness compression? Or make the same?

You can just follow step 5 in the manual

There is zero documentation to avoid approaching 0 dBFs or distortion skyrockets.

there is its step 5 in the manual

If I am playing some music through it, I have no control over the PCM samples.

it’s supposed to be uses with a DAW and you can adjust the output gain... Not to replete myself but its step 5 in the manual.

They are also extremely strict in not allowing products like this in that fail the basic test of near/at 0 dBFS output.

So they often go near 0dBFS in your broadcast industry or your DAW?

BBC spec: −18 dBFS = PPM "4" = 0 dBu
American Post: −20 dBFS = 0 VU = +4 dBu
Orchestral −18 dBFS = 0 VU = +4 dBu
Rock and / or Radio −16, or −14, or −12 dBFS = 0 VU = +4 dBu
Digi 002 is only capable of −14 dBFS.
German ARD & studio PPM +6 dBu = −10 (−9) dBFS. +16 (+15) dBu = 0 dBFS.

Headroom und Aussteuerungsreserve - ein häufiges Missverständnis EBU 0 dBFS -9 dBFS 0 dB -9dB full scale 10 ms attack time Einschwingzeit - sengpielaudio Sengpiel Berlin

Das Thema Headroom und Aussteuerungsreserve - ein häufiges Missverständnis EBU 0 dBFS -9 dBFS 0 dB -9dB full scale 10 ms attack time Einschwingzeit - sengpielaudio Eberhard Sengpiel

sengpielaudio.com

dBu in Volt dBV dBu Pegel dBFS digital audio dB Dezibel Umrechnung umrechnen Daempfung Verstaerkung 0 dBFS Bezug Bezugswert Referenzwert Erklaerung absoluter Pegel Logarithmus Verhältnis Dezibel Schalldruck Druck Spannungspegel dBFS dBVU 0 dB Audio S

Umrechnung dB dBu dBFS digital audio dB Dezibel dBV Pegel in Volt zur Tontechnik Erklärung Dämpfung Verstärkung 0 dBFS Logarithmus Bezug Bezugswert Referenzwert absoluter Pegel dBFS SPL Verhältnis Dezibel Spannungspegel Spannung Leistung dBVU dBFS 0 dB Audio Schall mW Rechner pro audio consumer...

sengpielaudio.com

 

[sergeauckland]

They are also extremely strict in not allowing products like this in that fail the basic test of near/at 0 dBFS output.

Agreed, although in practice, no broadcast digital signal should ever go above -10dBFS if the Sound Balancer is doing their job properly. The BBC is VERY strict about levels above PPM6, which equates to -10dBFS. Having said that, the whole point of headroom is that on the rare occasions it may be inadvertently exceeded, nothing nasty happens, which with this product it will, albeit it won't be in the on-air path, it being a monitoring tool. Regardless, if it were being used for Quality Monitoring, it couldn't be trusted, so useless.

S.