# Recommendations for hardware?



## dastrix (Oct 21, 2011)

Hi Everyone

Can anyone please recommend a USB Mixer, with XLR mic input, RCA inputs/outputs and that has a great frequeuency response? This would be to replace the soundcard in my laptop for room measurements

Ive had very poor success with the Audiogram 3 and also the MAudio Fast track (the latter has no inputs and the former has a bad frequency response)

Thanks
Kris


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## SAC (Dec 3, 2009)

The REW interconnect guide suggest the Behringer Xenix 502 with phantom power.

But as almost any reputable quality pre-amp has gain controls, and you want a 2 channel pre, they serve the same purpose.
The ART USB Dual Pre can be had for $69.


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## dastrix (Oct 21, 2011)

SAC said:


> The REW interconnect guide suggest the Behringer Xenix 502 with phantom power.
> 
> But as almost any reputable quality pre-amp has gain controls, and you want a 2 channel pre, they serve the same purpose.
> The ART USB Dual Pre can be had for $69.


And DOES the 502 has excellent freq response from the soundcard cause my previous attempts were rubbish!


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## SAC (Dec 3, 2009)

dastrix said:


> And DOES the 502 has excellent freq response from the soundcard cause my previous attempts were rubbish!


Why, at ~$49 I suspect the 502's pre-amps are absolutely world class. :rofl2:

But then I am not sure exactly how the additional functions provided by a mixer would be beneficial for that function anyway considering that REW is limited in its ability to process multi-channel measurements.

I would put my money on a unit the focuses more on its primary intended purpose rather than on a lot of bells and whistles.

Bottom-line is that I am not aware of any pre-amp below about $400 having extended frequency response or linear phase in the lowest octave or two or in the upper ranges. And none of those feature integrated hardware loopback compensation You get what you pay for.Thus its prudent to match your tools to the intended use. If extended response and linear operation, you spend more.


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## dastrix (Oct 21, 2011)

SAC said:


> Why, at ~$49 I suspect the 502's pre-amps are absolutely world class. :rofl2:
> 
> But then I am not sure exactly how the additional functions provided by a mixer would be beneficial for that function anyway considering that REW is limited in its ability to process multi-channel measurements.
> 
> ...


Ok, so the 502 and a soundcard

Sounds like the SoundBlaster USB is the way to go.

Is this the unit alot of people use?

http://www.ebay.com.au/itm/Creative...814?pt=LH_DefaultDomain_0&hash=item3f0f36369e


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## Wayne A. Pflughaupt (Apr 13, 2006)

Really dastrix, I don't see any reason why the M-Audio won't work, even if you can't generate a calibration file for it. My TASCAM US122 has ruler-flat response, and it cost half what your Fast Track does.

Regards,
Wayne


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## dastrix (Oct 21, 2011)

Hi Wayne maybe it was a faulty unit ?


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## Wayne A. Pflughaupt (Apr 13, 2006)

I guess you're referring to the calibration file. Since the Fast Track doesn't have a line input you won't be able to generate a calibration file. But like I said, I'm sure its of sufficient quality that it's not necessary. Most of the combo interfaces I've seen here were so good that the really don't need a calilbration file. As far as I can recall, that Yamaha you tried is the only one I've seen that didn't have virtually ruler-flat response.

Or where you referring to the level problem? I think that's probably a setting somewhere on your computer than needs to be changed. John is good at those issues.

Regards,
Wayne


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## dastrix (Oct 21, 2011)

Wayne A. Pflughaupt said:


> I guess you're referring to the calibration file. Since the Fast Track doesn't have a line input you won't be able to generate a calibration file. But like I said, I'm sure its of sufficient quality that it's not necessary. Most of the combo interfaces I've seen here were so good that the really don't need a calilbration file. As far as I can recall, that Yamaha you tried is the only one I've seen that didn't have virtually ruler-flat response.
> 
> Or where you referring to the level problem? I think that's probably a setting somewhere on your computer than needs to be changed. John is good at those issues.
> 
> ...


hi wayne, it was the the frequency response that was a dud... the level issue could be related to something else. Ill look into that.

I think ill go and buy a higher quality USB Audio interface and see how I go as I returned the Yamaha because of its frequency issues

I cant find a unit with XLR mic input and RCA Inputs/Outputs , most have a balanced intput thats not XLR, looks different...


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## SAC (Dec 3, 2009)

dastrix said:


> Ok, so the 502 and a soundcard
> 
> Sounds like the SoundBlaster USB is the way to go.
> 
> ...


So out of the above you come away with the idea that the Soundblaster is somehow appropriate?

As it readily accepts a mic input and supplies phantom power????

What exactly do you imagine yourself doing with a 'mixer' and a soundcard that does not readily natively accept a mic input and fails to supply phantom power?

We have already stated what is the most common configuration, and at each step you have a talent for side stepping it and proposing another solution that fails to address the basics in functionality and out of the box compatibility. 

Do whatever you like, but don't interpret what has been said thus far as an endorsement of a Soundblaster anything. ...And _then _you can try to figure out just what functional advantage having a 'mixer' affords you for this purpose.



Quit looking for a pre-amp with RCA outputs! And yes, you will need to employ an adapter on the balanced output to an RCA connector. Most will have balanced TRS outputs. So you might go to Monoprice and get a TRS to XLR cable, and RCA-RCA cable, and to Markertek for XLR-RCA adapter to join the two.


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## dastrix (Oct 21, 2011)

SAC said:


> So out of the above you come away with the idea that the Soundblaster is somehow appropriate?
> 
> As it readily accepts a mic input and supplies phantom power????
> 
> ...


You proposed a 502. That has a mic and phantom power. Thats what I was going to get , dont I also need a soundcard? the help topic suggested a live 24bit or a X-FI


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## SAC (Dec 3, 2009)

I proposed a 502 ONLY because you said you needed a 'mixer' and because that was already suggested in the REW interconnect diagrams. 
I also then described the 502's pre-amps as about as cheap as can be sourced, as well as questioned the need for a mixer.

I (and others) have repeatedly suggested a decent 2 channel pre-amp with phantom power that is configured to accept i mic input, the cheapest being the ART USB Dual Pre. But that is by no means the only pre-amp featuring that particular topology.


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## dastrix (Oct 21, 2011)

SAC said:


> I proposed a 502 ONLY because you said you needed a 'mixer'.
> I also then described the 502's pre-amps as about as cheap as can be sourced, as well as questioned the need for a mixer.
> 
> I (and others) have repeatedly suggested a decent 2 channel pre-amp with phantom power that is configured to accept i mic input, the cheapest being the ART USB Dual Pre. But that is by no means the only pre-amp featuring that particular topology.


Forget the money....I dont know what i need a mixer for, im assuming a mixer is what you plug a mic into... I dont know the terminology.

I tried 2 decent pre amps. the M Audio doesnt allow a self calibration as it doesnt have the input/output connector and the Yamaha produced a rubbish file, so as you can see so called 'quality' pre-amps dont really do what they say that do.

Your ART is NOT available here.


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## SAC (Dec 3, 2009)

The MAudio is a single channel pre-amp! _ Of course_ it will lack a 2nd channel for calibration or hardware loopback!
And the Yamaha, I have no idea what it is.

I really do not understand all the drama here.

Here is an ART USB Dual Pre in Australia, although the price is not very attractive.

And note, I _only _mention that unit as it is generally available _cheaply_, there is _nothing really special about it_ except that it has all the necessary features!

But the particular model is not that important! The capabily/configuration is!

And you will not find a balanced input device with RCA outputs!

Just go to any local MI store and look at their available 2 channel phantom powered mic pre-amps. Almost any will work, but anticipate using an adapter to convert the balanced output to an unbalanced RCA connector. And you might want to avoid Firewire interfaces simply due to the POTENTIAL for interface issues, as heaven forbid, we don't need more complications here. 

And make sure they have an acceptable return policy.......


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## dastrix (Oct 21, 2011)

SAC said:


> The MAudio is a single channel pre-amp! _ Of course_ it will lack a 2nd channel for calibration or hardware loopback!
> And the Yamaha, I have no idea what it is.
> 
> I really do not understand all the drama here.
> ...



Thanks SAC. And these ART devices generate, generally, a flat frequency response? With $80k with of audio gear im testing, I'd like something accurate


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## SAC (Dec 3, 2009)

Accurate for what? General passband testing rm ~20 Hz up to where? - yeah, about as accurate as the mic you use!

If you want below 20 Hz accuracy or high frequency accuracy, plan on spending substantially _more_ - for both a pre-amp and the mic! But if you need that, why are you not looking at a platform like Easera or, for live sound, SysTune?

I have previously posted measurements showing the difference between the TYPICAL moderately priced (sub $400) pre-amp and a quality unit such as the Duran Audio Axsys that DOES measure flat (in both frequency AND phase) from DC to gamma rays! And then you can start looking at the true lab quality mic - the_ least_ of which I would consider would be an Earthworks M30. 

We seem at very interesting(sic) diametrically opposed extremes here! On the one hand you are searching for ~$45 pre-amps in a market dominated by average performing $100-$600 units as we talk about how _performance_ is key!

So define your use and your parameters! THEN search for the units capable of delivering that level of performance. Thus far I don't think this has been done, else we would not have been talking the need for "quality" while we look at single channel pre-amps clearly not capable of being configured per the interconnect diagrams and ~$45 5.1 soundcards.


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## dastrix (Oct 21, 2011)

SAC said:


> Accurate for what? General passband testing rm ~20 Hz up to where? - yeah, about as accurate as the mic you use!
> 
> If you want below 20 Hz accuracy or high frequency accuracy, plan on spending substantially _more_ - for both a pre-amp and the mic! But if you need that, why are you not looking at a platform like Easera or, for live sound, SysTune?
> 
> ...


I dont think I ever mentioned money at all, you just assumed I wanted a cheap unit 

Ill look at those software packages, My microphone is being calibrated by a sound lab here locally next week (RTA Associates). I'm more than happy to look at more quality software packages and preamps, I just dont know what 'quality' is

I have thought a yamaha unit would be excellent, not so.

I dont need alot of features on the pre-amp, just something thats quality!


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## SAC (Dec 3, 2009)

No. 

What you _need_ to do is to precisely define WHAT you want to do!

No one Needs a Terex truck or a Bentley to go to the corner grocery. Conversely a Toyota Corolla will not suffice for competing at LeMans. The application requirements define the appropriateness of the equipment!

You define exactly what your present and future needs are, and THEN you determine what measurement package and level of precision/performance is required!

It may be that an intro level pre-amp (capable of meeting the base configuration requirements) and mic are sufficient. The same with REW. They may not, based upon the measurements and the degree of accuracy required!

Precisely define your needs and any limiting factors. That is what determines the level of performance required.


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## dastrix (Oct 21, 2011)

Need, to measure a room with as much accuracy as possible from 20hz to around 20,000khz. Whilst money isnt a huge issue, its most likely not worth spending gabillions on this... so lets be sensible


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## LastButNotLeast (Sep 14, 2011)

dastrix said:


> Thanks SAC. And these ART devices generate, generally, a flat frequency response? With $80k with of audio gear im testing, I'd like something accurate


I got a "restock" MobilePre MkII for <$60. You can see the difference in frequency response in my post from elsewhere:
http://www.hometheatershack.com/for...ut-wizard-check-out-graph-pls.html#post468466


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## aackthpt (Jan 24, 2011)

dastrix said:


> Ok, so the 502 and a soundcard
> 
> Sounds like the SoundBlaster USB is the way to go.
> 
> Is this the unit alot of people use?


I have seen good reported results with behringer UCA-202 / UCA-222 (looks like same unit with different software bundle). That should work fine with the little mixer if you can't easily get your hands on a preamp/USB interface combo unit.


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## SAC (Dec 3, 2009)

dastrix said:


> Thanks SAC. And these ART devices generate, generally, a flat frequency response? With $80k with of audio gear im testing, I'd like something accurate


So the porridge needs to be just right...



dastrix said:


> I dont think I ever mentioned money at all, you just assumed I wanted a cheap unit
> … I just dont know what 'quality' is
> I dont need alot of features on the pre-amp, just something thats quality!


So this porridge is too cold...



dastrix said:


> Need, to measure a room with as much accuracy as possible from 20hz to around 20,000khz. Whilst money isnt a huge issue, its most likely not worth spending gabillions on this... so lets be sensible


So the porridge too hot...



dastrix said:


> Sounds like the SoundBlaster USB is the way to go.



Hmmm. Rather than progress, this has devolved into the Scarecrow scene from the Wizard of Oz.

We mention the lowest recommended package and we are told we want “quality”, with no idea of what “quality” is. So we mention options where “quality” is determined in terms of higher levels of actual performance and not simply labels, ranging in total price from around $200-$1000 including a decent mic) and we are to that “its most likely not worth spending gabillions”. 

Thus far the only use indicated has been for measuring “the frequency response” – for which all of the gear is, quite frankly, overkill; as a frequency response is of little value. And then the option considered is a ~$29 sound card and a $49 /mixer’ whose price and summed internal 'self' noise levels exceed the both the price and noise levels of the cheapest Pre-amp we suggested.

Let’s see, considering that the system is not simply $80k worth of boutique gear, and that you likely have spent more money on interconnects than on any option that we have thus far suggested, I agree. It’s long past time to be “sensible”. 

You need to sit down and literally figure out just what it is you desire to measure and what you expect to achieve – be that complex impedance measurements to dual channel FFT measurements. Then buy the gear that is accurate and precise enough over the entire bandpass you think you need in order to achieve the results you imagine yourself wanting.

Best of luck.


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