Hi fellow SOS-ers,

I have recently bought a second set of monitors and would like to use both sets I now own to do some A-B switching while recording & mixing. I have RCA cables for both sets.

What is the best option to achieve this on a budget of up to 200 pounds? Should I get a sound card that is capable of 4 RCA outputs? I was thinking of a monitor switch controller such as the Mackie Big Knob or the Samson C1 Controller, but their functionality seems like overkill for what I need to do.

Any opinions and suggestions would be most welcome!!!!!!

Kam.

The SM Audio M-Patch 2 is a passive monitor controller with switching for two sets of speakers, plus a headphone amp and a secondary input (so you don't need to boot the computer just to listen to your mp3 player or whateaver.

Good quality and good value... and although it is nominally balanced in and out, it will work quite happily with unbalanced signals while allowing you to upgrade your system and connections later without additional outlay.

You can read Martin's review of it here:

http://www.soundonsound.com/sos/dec06/articles/smprompatch.htm

Hugh

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Technical Editor, Sound On Sound

Hi Hugh,

Thanks for the lightning quick response!

Follow-up question:
I'm afraid I got a little confused when you said
"while allowing you to upgrade your system and connections later without additional outlay"

Are you referring to if in future I wanted to upgrade say, my sound card but still wanted to keep the capaility to use 2 sets of monitors?

Cheers,
Kam.

Hi!

I think Hugh means that since the SM Pro M-Patch 2 I reviewed has a passive main signal path, it will still be a useful purchase if you later on upgrade everything else in your chain (audio interface, loudspeakers, and so on).

This is because the audio will pass through it with virtually no change at all, whereas a Big Knob or C1 controller has active circuitry, and at the bidget prices of those two controllers this active circuitry will result in a noticeable change to the sound.


Martin

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YewTreeMagic

not only active circuitry - but cheap active circuitry. Nothing wrong with active systems but there IS a lot wrong with cheap ones. SM is the way on this budget.

Thanks guys - great feedback as always.

Much appreciated! Time to go find a good price...

Cheers,
Kam.

Quote narcoman:

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not only active circuitry - but cheap active circuitry. Nothing wrong with active systems but there IS a lot wrong with cheap ones. SM is the way on this budget.

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Would you care to elaborate?

A passive attenuator must be a compromise between preserving a low enough source Z to prevent in band HF loss but not so low as to unduly load the source (which by definition will be an unknown).

I cannot see that even the humble TL071 wired as a unity gain buffer is going to have much effect upon a signal chain.
An active attenuator might audition differently from a passive one because it is slightly brighter and thus in fact more accurate?

I would be interested in seeing the results of any tests/clips done in the area.

Dave.

Why do some people feel the need to spend money when it is totally unnecessary?

Just stick the ins and outs on a patchbay. We have a desk that has all kinds of magic switching and combining of monitors, but that is just total overkill and we now just feed the patchbay and can run four different 5.1 systems in any combination. (You could also use a £5 wafer switch, or one of those £15 D-Sub switch boxes.)

Quote ef37a:

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Quote narcoman:

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not only active circuitry - but cheap active circuitry. Nothing wrong with active systems but there IS a lot wrong with cheap ones. SM is the way on this budget.

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Would you care to elaborate?

A passive attenuator must be a compromise between preserving a low enough source Z to prevent in band HF loss but not so low as to unduly load the source (which by definition will be an unknown).

I cannot see that even the humble TL071 wired as a unity gain buffer is going to have much effect upon a signal chain.
An active attenuator might audition differently from a passive one because it is slightly brighter and thus in fact more accurate?

I would be interested in seeing the results of any tests/clips done in the area.

Dave.

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switching circuit.

Second - audition the options.... you get no such loss on such short signal runs. The attenuator itself? If it's going to be active then it better be GOOD active. Tried the big knob. Just utter crap.

Quote narcoman:

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Quote ef37a:

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Quote narcoman:

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not only active circuitry - but cheap active circuitry. Nothing wrong with active systems but there IS a lot wrong with cheap ones. SM is the way on this budget.

---

Would you care to elaborate?

A passive attenuator must be a compromise between preserving a low enough source Z to prevent in band HF loss but not so low as to unduly load the source (which by definition will be an unknown).

I cannot see that even the humble TL071 wired as a unity gain buffer is going to have much effect upon a signal chain.
An active attenuator might audition differently from a passive one because it is slightly brighter and thus in fact more accurate?

I would be interested in seeing the results of any tests/clips done in the area.

Dave.

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switching circuit.

Second - audition the options.... you get no such loss on such short signal runs. The attenuator itself? If it's going to be active then it better be GOOD active. Tried the big knob. Just utter crap.

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So, in other words you know of no such tests?

Dave.

A switch box is quicker and easier to use than a patchbay. Not as flexible, obviously, but if your requirements are simple the patchbay doesn't offer an advantage.

Moreover, cheap patchbays are unreliable and expensive ones are... er... expensive. And they provide a lot of connection points that the OP probably doesn't need.

A wafer switch is cheap. A good one is a little more expensive. And it requires a box and some connectors which push the price up considerably further. And it takes time and some engineering skills to manufacture which the OP may not have or be willing to do.

In my opinion, the SM Audio is a very cost effective alternative that does precisely what is required at a very modest price, and represents an investment in a piece of equipment that will never be outgrown -- it will always find a use somewhere. You can't say that about many things!

To Dave: Nothing wrong with a TLO72 at all if it's used properly... but so often in budget gear it just isn't. Inadequate power supplies restrict headroom. Bad board layouts compromise crosstalk and bandwidth... and so on and son on.

Yes, a passive controller has its limitations, but I would pick a passive over a cheap active any day. An understanding of the technical implications in terms of source and load impedances and cable lengths is helpful, but in practice the vast majority of installations will work perfectly well with zero effort. Most active driven outputs have a surce impedance of a hundred ohms or so, and most active inputs are around 50k or so... which leaves a lot of lee-way for a passive attenuator system without compromising HF response across a sensible bandwidth.

Good active is another thing entirely and the preferred route if the budget allows, as narcoman said.

As for tests, we have reviewed a wide range of monitor controllers. Some have been quite disappointing from a sound quality perspective...

hugh

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Technical Editor, Sound On Sound

Thank you Hugh,
a measured respose is all I crave!

Flat out "X is crap" helps no one ( has Paul stil got his BK. He was quite taken with it in Feb 2005!)

And MC shootout? When fcs? I missed that and get the rag religously.

I would like to see more comparison tests, sacred cows need prodding occaisionally, re the clocking "fiasco"?

Dave.

I'm routinely measuring everything that passes through my hands these days using an AP test set.

Yes, PW does still use a Mackie Big Knob as his monitoring controller and seems happy with it. I use a custom unit made for me by Audix broadcast when working on location and either a Grace Design M902 or an SM Audio Nanopatch for other applications... Does that tell you what you want to know?

Personally, I'm not a fan of shootouts because they often highlight irrelevant or misleading aspects of performance... although we do seem to be publishing more of that kind of article these days. A shootout comparing small diaphgram capacitor mics is planned for the next issue, for example.

hugh

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Technical Editor, Sound On Sound

i've always wondered , if PW used the BK, because of some subconscious male impulse, as opposed to the ears...


i've auditioned and used all sorts of monitor controllers , and the BK comes n nowhere near the top of the pile,. either for usability, or for sound.... and it's proclivity for indulging in earth loop shenanigans has been the bane of many client's lives....

the difference between that, and say the Presonus Central Station, is immediately sonically obvious.....


what's astonishing , is the SM units performance.... it's far better than a unit of that price has any right to be.

Quote ef37a:

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Thank you Hugh,
a measured respose is all I crave!

Flat out "X is crap" helps no one ( has Paul stil got his BK. He was quite taken with it in Feb 2005!)

And MC shootout? When fcs? I missed that and get the rag religously.

I would like to see more comparison tests, sacred cows need prodding occaisionally, re the clocking "fiasco"?

Dave.

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What did Hugh say that was any different? I just put it in a nutshell..... it helps cuz (arrogant statement alert) it's from me .... trust me. I am a doctor.


More usefully - the top end distorts slightly (those of you have used an SPL vitalizer will know the sound)..... Worth the money? Actually no.... because you are not hearing your mix. The SM stuff, for the price, does the job brilliantly. The Presonus too (although the remote has a few issue with HF loss). Those two I can recommend. The BK I can recommend selling it.....

I've got an Avocet in one room and an XMON in another - both active and both extremely good. I've also got SM gear in edit rooms and (still) got a BK around. Also still have, but no longer use the Presonus.

Shoot outs are an utter waste of time and useful to no-one.

Quote narcoman:

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More usefully - the top end distorts slightly (those of you have used an SPL vitalizer will know the sound).....

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A lot of budget gear does when the level gets above about +10dBu. I have a Mackie 1402VLZ console that gets very obviously unhappy in the HF end once the signal exceeds about +10dBu. Sure... it will pass +20dBu, but not nicely at the high end.

So, if you're working with a typical D-A converter that has been aligned to provide between +18dBu and +24dBu for a 0dBFS digital signal, and you are working with full scale or nearly full scale signals, a budget analogue signal chain is going to struggle a lot.

Well designed active pro audio gear will cope. Budget stuff will tend to sound strained and hard. A passive interface circumvents that problem (although the analogue stages of the D-A converter might still be an issue...).

hugh

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Technical Editor, Sound On Sound

Should probably qualify it with a "fitness for purpose" stamp though. The BK is still a good solution for home users who need a few proper studio facilities. The issues with it don't really become apparent until you're working in a high end environment and on projects that are sensitive to those sort of elements.

Yup, as long as there isn't some huge impedance mismatch, passive designs can work very well.

SM Patch or the TC Electronics Level Pilot work well for their money especially for lower priced monitors.

With the PSI A21-M I'm going to be using the Goldpoint SA1X stepped attenuator. About as good as it gets for passive designs. Using 10K resistors, the input of the PSI is 10K balanced as well, so its a good match.

Quote narcoman:

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The BK is still a good solution for home users who need a few proper studio facilities.

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Doh!

Only just 'got' that abbreviation - thought you were talking about a monitor controller from Brüel & Kjær


Martin

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YewTreeMagic

Burger King

Quote narcoman:

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Burger King

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Bacon double cheese... Mmmmmmmmmmmmm

Andy

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When the going gets weird, the Weird turn Pro.

Quote narcoman:

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Should probably qualify it with a "fitness for purpose" stamp though. The BK is still a good solution for home users who need a few proper studio facilities. The issues with it don't really become apparent until you're working in a high end environment and on projects that are sensitive to those sort of elements.

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Better Narcoman (see, you CAN be nice!).

After all you would not call an AC15 "crap" just because it cannot fill the RAH with lucious clean tones?

My 2496 has an absolute maximum output of +2dBV(it never gets close and a noise floor some 96dB below 0dBFS) thus the BK would never be embarrassed slotted in between it and my Tannoy 5a's. I would suspect that there are vastly more SoS readers running at those sort of levels than are ever hitting +10dBu never mind +23!

BTW. Where are all the entreprenurial "bodgers" these days? I well recall Tape Recorder mag modds to the A77. An excellent deck but cursed with daft switching and "unpro" ins and out. There were several commercial firms that would "pro" a 77 and the Ferro Series 7's.

I am sure the BK could be changed and a beefier output stage fitted?

Dave.

Quote Martin Walker:

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Quote narcoman:

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The BK is still a good solution for home users who need a few proper studio facilities.

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Doh!

Only just 'got' that abbreviation - thought you were talking about a monitor controller from Brüel & Kjær


Martin

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Now! If THEY made a monitor controller?????!!!!


Dave.

Quote ef37a:

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Better Narcoman (see, you CAN be nice!).

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Never knowingly.

Quote ef37a:

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I am sure the BK could be changed and a beefier output stage fitted?

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Yup - too right. In fact do such a mod and you'd have a GREAT unit since the facilities are good. Jim Williams would be a good man here...

Quote ef37a:

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I would suspect that there are vastly more SoS readers running at those sort of levels than are ever hitting +10dBu never mind +23!

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I'm not so sure. The vast majority of interfaces are geared up for more standardized levels in the +18 to +24dBu range. Of course, many also offer -10dBV options too, and in my experience they often work and sound rather better when switched to that mode for the reasons already discussed.

Quote:

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BTW. Where are all the entreprenurial "bodgers" these days? I well recall Tape Recorder mag modds to the A77.

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Two reasons they are absent: fear of litigation should someone damage themselves or the equipment when following published 'advice', and the inherent difficulty of modifying equipment constructed using surface mount components, multi-layer PCBs and firmware control systems.

Quote:

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I am sure the BK could be changed and a beefier output stage fitted?

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It could... but if you want a Jag XJR experience you won't get there by bolting a bigger engine in a Mondeo...

It's not just about adding a beefier output stage. It's about power supply design (headroom and noise), PCB layouts (crosstalk, distortion, stability and bandwidth), choice of components and switches (reliability, accuracy, noise, distortion...)... We are talking about trying to improve upon fundamental design decisions taken in the interests of costs, not ultimate quality, and as a result, it is very difficult to achieve the kind of overall improvement you seek.

Yes, a beefier output stage will allow it to drive more difficult loads to greater levels. But the front end will still struggle with high input levels. The bandwidth will still be limited, noise and distortion in earlier stages will still be an issue.

Cleaning the windows won't help if the net curtains stay up!

High end devices are designed holistically -- the whole design has to be right, otherwise you're just replacing one weak point with another.

hugh

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Technical Editor, Sound On Sound

Quote Hugh Robjohns:

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It could... but if you want a Jag XJR experience you won't get there by bolting a bigger engine in a Mondeo...

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hee.... that wouldn't be too far wrong......

Quote narcoman:

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Quote Hugh Robjohns:

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It could... but if you want a Jag XJR experience you won't get there by bolting a bigger engine in a Mondeo...

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hee.... that wouldn't be too far wrong......

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Ooo I don't know? Couple of Burr-Browns on a bit of perf'...and just FYI, some of the max outputs of the more common AI's that have been thru' the SOS mill..
M-A 192 +14dBu
M-A ULTRA +10
Saffire 6 +9
Saffire 40 +15.7 (at 0.88%thd!)
RME Baby face +15
TC Impact twin +12

Dave.

Internal sound cards and bus-powered interfaces generally operate with lower power rails and thus lower output levels. But even so, five out of the six you mentioned will all start to press the 'hard zone' of some of the budget monitor controllers we were discussing.

Someone working with a modest interface will probably find a modest monitor controller entirely adequate -- as you suggested yourself earlier. But someone working with more upmarket outboard converters will soon discover the limitations... as narcoman discovered.

As I said before, there are ways of minimising the potential problems, but the fact remains that cheap equipment is always cheap for a reason, and most good expensive equipment is expensive because doing it right is inherently more expensive.

Going back to the passive controller idea, within certain physical constraints involving cable lengths and impedances -- which are rarely a problem for most -- there is no quality bottle neck to worry about.

...but you might not always get all the bells and whistles of other active systems.

Hugh

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Technical Editor, Sound On Sound

"But even so, five out of the six you mentioned will all start to press the 'hard zone' of some of the budget monitor controllers we were discussing."

Really? Would you really want to be running an AI that close to its limit? Surely you would want to be 10dB under nearly 1%thd?

Still, message understood all round I think. Anything can be "crap" if it is not used appropriately!

Dave.

Quote ef37a:

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"But even so, five out of the six you mentioned will all start to press the 'hard zone' of some of the budget monitor controllers we were discussing."

Really? Would you really want to be running an AI that close to its limit? Surely you would want to be 10dB under nearly 1%thd?

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It depends whether you're talking about digital or analogue on your audio interface

I run the digital output of my ancient Echo Mia into the digital input of my Lavry DA10, and that can generate extremely high output levels with no 'hard zone'. Set to maximum it can manage 24dBu balanced = 34.72V peak to peak = 12.28V r.m.s


Martin

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YewTreeMagic

Quote Martin Walker:

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Quote ef37a:

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"But even so, five out of the six you mentioned will all start to press the 'hard zone' of some of the budget monitor controllers we were discussing."

Really? Would you really want to be running an AI that close to its limit? Surely you would want to be 10dB under nearly 1%thd?

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It depends whether you're talking about digital or analogue on your audio interface

I run the digital output of my ancient Echo Mia into the digital input of my Lavry DA10, and that can generate extremely high output levels with no 'hard zone'. Set to maximum it can manage 24dBu balanced = 34.72V peak to peak = 12.28V r.m.s


Martin

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Hi Martin.
Certainly analogue, I was quoting the max out spec from the user manuals.

The Lavry is superb but I am not talking about such rarified equipments, just the stuff most of us have to get by with.

Dave.