USL MMP-10 microphone multiplexer price.

[Jose Angel Velasco]

Hello.
They are offering me to buy an used MMP-10, but we don't know its price. What was its new price and what could be an appropriate price for a used one?

[Marco Giustini]

Bear in mind that with today's multi-input sound cards the need for a multiplexer has gone.

That is, older sound cards were only 2 channels so to have 4 or more microphones you had to "multiplex" them before the input.
With newer cards you can route the 4 or 8 inputs straight into your RTA software and ask the RTA to do a live average.

Smaart can do that - the advantage is that you don't need any extra HW, you can see the single readings in real time and you have much more signal to work with - I mean, with a multiplexer the sound is being switched through all the mikes, say once every second. That means that your RTA will receive 1 second of data from each microphone in 4 seconds of time.

With a dedicated multi-channel card, your RTA will receive 4 seconds from each microphone in 4 seconds of time.

The bottom line: check the price of a good quality multi-channel USB sound card and that will replace the multiplexer entirely.

[Jose Angel Velasco]

To the price of a 4 channel soundcard you must be add a software license of a RTA like Smaart.
I want the multiplexer for connect it directly to a JSD-60 sound processor that has a built-in RTA.

[Marco Giustini]

ahh, of course.

In that case I guess it is an option. That said, just bear in mind that Smaart with 4+ microphones will give you much more. But yes, it comes with a price.

[Steve Guttag]

Honestly, between the D2 (multiplexer based) and Smaart with the same (or more) mics, I prefer the results with the D2. The MMP-10 uses the multiplexer part of the D2 (or vice-versa, depending on your vantage point)...except the D2 uses calibrated mics and normalizes the levels.

Smaart definitely has more to offer in the analysis department, including time alignment measurements but when it comes to actually reading the RTA and getting consistent results, the D2 system, for me, seems to be a lot more repeatable and trustworthy and getting a representation of the room.

[Tony Bandiera Jr]

Y'all are tap dancing around his question. Valid responses, of course, but not what he is asking.

To answer his questions about cost: I used to have one of those MMP-10's, and if memory serves it cost me around $800 USD new.

I later sold it when I got out of the full time tech work for around $450-500.

So at this time, a reasonable price for a complete kit (including the mic clips, cable, adapter and so on) would be around $300-500 USD.

[Marco Giustini]

Steve,

Indeed Smaart is lacking the level normalisation feature - but I wouldn't think it's such a deal breaker. It's interesting to hear your experience. I haven't used my D2 in a while, and I also have Smaart. My D2 is the one with the 4Pre so I can use both with multi-mike.

Too bad that whenever I am called to "check the sound" it's usually a "do what you can in the 20 minutes we give you" exercise.

[Stefan Scholz]

I use all of the mentioned, still have my R2 from the 90s, with a disintegrating plastic shell on the Dell latitude (color screen VGA) laptop from 1993, the D2 and a Smaart with 8 microphones.
Actually the microphones are the expensive art, not the software license, training class or audio card.
Roland Octa Capture has ben a recommended audio interface, featuring 8 fantastic microphone inputs with extremely high dynamic range. Using low sensitivity microphones, an extraordinary wide measuring range can be accomplished. Really needed? Well, in science and noise monitoring, that's oK.
For installed sound? There's just one important, to have enough measument level above the noise floor. Going for 70 @ 7.0 (or some misinterpretation 85 dBC on the SPL meter) is pretty noisy, and not required in a quiet room with idle noise in the 20 dB range.
Regarding microphones, one of the trainers pointed out, the price of expensive, matched pairs/ quadruples or octetts is not really worth it. You don't even need a high quality class 2 or 1 microphone. (Which is the case for legal activity upfront a court as proof of trust) Take the cheap $ 40 mic, place it together with a $ 1500 mic in the same spot. The measured deviation is less than a dB.
Take any 1 foot apart. The deviation can reach 10 to 20 dB, depending on location and frequency band.
The advantage of expensive microphones is little. Calibrated one come with a measurement printout, which states it was checked after production, therefore DOA is unlikely. Plus expensive one have a solid lathed and polished exterior of heavier duty. Cheap ones may be assembled with heat glue in a less fancy shell, which when dropped to the floor, falls apart.

The D2 (and R2) microphones are nice and very small, and delicate to handle in a certain way. The larger 1/4" class 1 mikes from the Smaart kit are more robust.

In my field work, I have stayed with the D2 and the method we were trained in Lucas Valley and SF in the 1990s. It proves extremely well and repeatable within a reasonable time needed for the adjustment.
Smaart offers more detailed analysis and higher resolution, plus I like the time domain feature, that allows to determine speaker and room related issues. Used for special needs

[Gordon McLeod]

You see the original USL on Ebay several times a year in the 300-400 range
I still use the R2 on my work bench and use Oracle virtual box to run in from a rack mounted computor in my test bench. In the field I use the D2 and it is very good and repeatable

[Marco Giustini]

Take any 1 foot apart. The deviation can reach 10 to 20 dB, depending on location and frequency band.

I learnt that the very first time I walked in an auditorium with a microphone to experiment. It was immediately clear that sticking ONE microphone on a stick and dial "the X curve" was a waste of time (or at least a very inaccurate way of doing an EQ).

[Steve Guttag]

Using 1 mic is definitely more-tricky! It is always a good idea to "walk the room" with pink noise playing an before settling on a mic location (regardless of 1 or many) to listen to what the mic will be listening to to ensure you are not in an odd spot (node) and is representative of the room.

Smaart does have mic normalization, of sorts (it came along in version 8...not at first but one of the revisions. Under New Spectrum Average...there is a tickbox to "Normalize."

[Marco Giustini]

Ah, thank you Steve, I wasn't aware of the "normalise" feature. I'll take a look.

When only using one microphone I do walk the room... with the microphone! When time is very limited and multi-mike is not an option I find it's the only way to get a reasonable result.

[Gordon McLeod]

The original Imax method of EQing was done with the audio tool box and a single mic that averaged continously as it was walked around the room