Hifi preamp vs passive monitor controllers

[jimjazzdad]

I built one of these a few years ago and it has served my studio well: http://www.audiotechnology.com.au/wp/index.php/on-the-bench-diy-monitor-controller/ (hope its OK to link). Not to take away from the excellent products discussed here, but passive monitor controllers are pretty simple to build and sound great when using a bit of care and quality components. I built mine as a balanced unit using TRS jacks in an angled aluminum encolsure, so it look a bit different than the one in the DIY article. I also added a in/out switch for a sub. All for less than $100 and a pleasant afternoon of tinkering.

[ef37a]

I am not a great fan of passive controllers for all the reasons so far mentioned but, the main drawback that I can see is the higher than desirable output resistance and its variability? A couple of balanced line drivers would solve that in short order and allow the passives to drive long lines to monitors.

Talk will no doubt follow about "transparency"? Well a couple of unity gain NE5532s are probably as spring water compared to the front ends in most sub £1000 monitors!

Oh! And I would LOVE someone to tell me how and what causes the Big K to be "coloured"?

Dave.

[Dan B]

Thanks again for all the responses.

Ok, now I'm a little confused!

My only concern here is fidelity. Given that I can operate either a c. 3m balanced or c. 1m unbalanced lead (and it's usually the latter) from the output of the controller to the power amps, I'm guessing that the disadvantages of a passive system aren't much of an issue here? Or there might be solved by a line driver?

At the input end, there's an unavoidably long run from the RME soundcard to the C500, but by using a passive or active monitor controller would enable me to switch that to a balanced one. Which in itself should provide a little benefit.

Many users of inexpensive passive controllers (like the new Big Knob passive or the M Patch 2) report that they're far from transparent. This is a concern as it may not be a step up from the C500.

My budget for a volume control is limited. Well, unless it was really going to make a night and day difference - but I suspect that kind of money would be better spend upgrading amps, speaker or D/A (currently an RME UCX, although I could use - but don't - a Focusrite Clarett Octopre). So it seems we're either looking at

(i) staying with the status quo (hurray - no £££ or time spent rewiring required);
(ii) a cheap passive controller (£50-100); or
(iii) an active controller (pick of the bunch on a budget seems to be the CMC2 for £215).

The only testing I can currently do is to take the C500 out of the picture completely to see if that sounds noticeable more transparent, but (a) that'll still be running on a long unbalanced cable and, more importantly (b) given the time that takes, my audio memory is likely to be totally unreliable to measure that kind of difference. Is there a more scientific approach I should adopt here?

Yours confusedly,
Dan

(As always, I'm probably looking for simple objectively verifiable answers, when the answer is probably "it's complicated"! )

[James Perrett]

My only concern here is fidelity. Given that I can operate either a c. 3m balanced or c. 1m unbalanced lead (and it's usually the latter) from the output of the controller to the power amps, I'm guessing that the disadvantages of a passive system aren't much of an issue here? Or there might be solved by a line driver?

That unbalanced connection on the output is going to make the whole system unbalanced with a passive controller - this really points to you needing an active controller like the Drawmer.

Personally I'd try the direct route first. If you really hear a difference then it would be worth replacing the Cambridge amp but I'm less worried that Hugh is about long unbalanced connections provided the driving end has a suitably low output impedance (which the RME will have) so I'm not sure that you'll hear a huge quality difference.

[ef37a]

Sorry if I have confused you Dan!
My view like others is you either stay as you are or splash for a 'proper' active controller.

My impudent interjection was meant for someone who perhaps had a cheap passive controller and was a bit worried about the output drive situation.

I had myself considered getting a passive box but with the mod I outlined (got a PCB somewhere with chip drivers already made up) However, that was when I was running a 2496 card my main PC now runs the NI KA6 most of the time and that has the handy BK on top!

Dave.

[Dan B]

Thanks. Looks like I'm down to the CMC2 or status quo. Will try to do some experimenting, though if there's a more scientific approach I can adopt, I'm up for trying that too!

Off topic, but the upshot of my earlier post today led me to check out RME specs vs Focusrite Clarett. That might lead to a more appreciable (and free!) difference. I've been using a RME UCX for my D/A, but could run ADAT out of the RME into the Clarett Octopre, clocked to the RME (master) over Wordclock, for my D/A instead. Based on the spec below, that ought objectively to be an improvement (unless there's something not covered by the spec above that might contribute to the sonic performance of the D/A...?).

Focusrite Clarett
Cirrus Logic CS4398 Stereo DAC - AK4413 DAC for multi line outs, CS4398 for Monitor out (but no monitor out on the Octopre).

Dynamic range ADC 116 dB
THD+N 0.005% = -86 dB

Dynamic Range DAC 119 dB (Line Outputs)
Dynamic Range DAC 117 dB (Monitor Outputs)
THD+N 0.0007% = -103 dB

RME Fireface UC (I assume the same as my UCX)

Dynamic range ADC 113 dB
THD+N 0.0012 % = -98 dB

Dynamic range DAC 113 dB
THD+N 0.0015 % = -96 dB

[James Perrett]

Personally I wouldn't bother with the added complexity as both would appear to perform to a high standard given those numbers. However, those numbers also only tell part of the story as things like output impedance over the whole frequency range are also going to make a (very very) slight difference with the long cable run. You also need to check whether any weighting has been used to improve the numbers.

[Hugh Robjohns]

You seem to want to change the setup just for the sake of changing the setup -- but if what you have does what you need/want, why mess with it?

Your current preamp is a quality hifi design from a company that knows what it's doing, and it clearly does what you need as a source switcher and volume control. A passive controller design may be fractionally more transparent, but I'm not convinced you'd be able to hear the difference as it would be pretty small, but the very real downside is that it may also introduce equipment matching problems which you don't currently have... or it might not if you can work with short cables and appropriate impedances.

And while there is a marginal difference in tech specs between your interfaces, you'd need very much better monitors than you have -- and a very well sorted room -- to hear that tiny difference.

H

[Dan B]

Thanks all. Very happy to hear the "don't change what ain't broke", especially when that means not spending any more money!

I'm guessing that whatever marginal improvement (if any) might be had by the CMC2, it'd not a good value proposition for £215 odd.

My rooms as well treated as it can reasonably be... Perhaps if I'm going to spend anything, I should instead start saving for a monitor upgrade - not least as that just leads to generally improved enjoyment for day to day listening as well even when not working. I'd be lying if I wasn't a little tempted by the Neumann KH310... A fair bit more than £200 odd mind...!

[Forum Admin]

Thanks all. Very happy to hear the "don't change what ain't broke", especially when that means not spending any more money!

Well you might not have ended up spending any more money, but Hugh's ringing endorsement of the Drawmer CMC2 -- plus the fact my current mono-check setup is a little convoluted and the CMC2's dedicated Mono Out fits better -- has just resulted in me placing an order for an active CMC2 to replace my passive M-Patch2.

GAS...

[Matt Houghton]

Glad their new versions are getting some attention. Look forward to reading it. Is it in April issue?

I think you misunderstood. It's not a new Mackie unit I was reviewing. It was another device entirely, which just happens to hold the same potential for innuendo: nOb

This isn't a monitor controller (but it is really good, and there's much more to it than a first impression might suggest...). But I digress...

[Forum Admin]

I've been doing a lot of misunderstanding of forum posts lately... always in a rush and skim-reading... bad habit.

nOb looks interesting. I've got a Faderport 8, macros, keyboard shortcuts and my mouse -- not forgetting my Novation RemoteSL controller -- so personally, I am unlikely to want another thing to twiddle plug-in controls, etc. But others might.

[Martin Walker]

Glad their new versions are getting some attention. Look forward to reading it. Is it in April issue?

I think you misunderstood. It's not a new Mackie unit I was reviewing. It was another device entirely, which just happens to hold the same potential for innuendo: nOb

This isn't a monitor controller (but it is really good, and there's much more to it than a first impression might suggest...). But I digress...

Ah great, it's that wonderful steampunky one!



Looking forward to reading your review Matt , although I might be tempted to buy one just for its looks

Martin

[Matt Houghton]

...the fact my current mono-check setup is a little convoluted...

My monitor controller is a quality one (Dangerous D-Box) but lacks a few facilities (e.g.: no mono to one speaker, just dual mono; no Sides solo). But rather than go on a hunt for the perfect controller, I decided to stick with the D-Box and enact all the tricky stuff in Cubase's Control Room. The advantage is that I can do it all with keyboard shortcuts — I don't even need to reach for a controller!

[Forum Admin]

Every pro studio should own one and label it, "A&R Control" -- like they used to do in the '80s/'90s on SSL desks with a bus fader routed to nothing, just so the A&R man could twiddle it and convince himself that his level setting was better, and the mix should be printed like that!! (tee-hee)

[Matt Houghton]

nOb looks interesting. I've got a Faderport 8, macros, keyboard shortcuts and my mouse -- not forgetting my Novation RemoteSL controller -- so personally, I am unlikely to want another thing to twiddle plug-in controls, etc. But others might.

Well, I won't give everything away in advance! But a few things that are really useful about this one are that it offers greater precision than MIDI controllers or a mouse scroll wheel, more precise physical control than a mouse/trackpad, and the ability to recall/reposition windows from multiple applications to bring parameters under instant control. I'll leave it at that for now — I'm derailing the thread!

[Forum Admin]

...rather than go on a hunt for the perfect controller, I decided to stick with the D-Box and enact all the tricky stuff in Cubase's Control Room. The advantage is that I can do it all with keyboard shortcuts — I don't even need to reach for a controller!

I currently do something similar in Studio One Pro controlling the Studio 192. But doing it in the DAW is fine for mixes/tracking, but there are times I like to have my CD player routed to my 'B' speakers without the computer turned on, when I'm using it for background music while re-stringing a guitar, or tidying up cables etc.

Horses for courses.

[Matt Houghton]

...rather than go on a hunt for the perfect controller, I decided to stick with the D-Box and enact all the tricky stuff in Cubase's Control Room. The advantage is that I can do it all with keyboard shortcuts — I don't even need to reach for a controller!

I currently do something similar in Studio One Pro controlling the Studio 192. But doing it in the DAW is fine for mixes/tracking, but there are times I like to have my CD player routed to my 'B' speakers without the computer turned on, when I'm using it for background music while re-stringing a guitar, or tidying up cables etc.

Horses for courses.

Yeah, I have it set up so I can use the monitor controller for source/speaker selection without firing up the computer. But I can also switch more advanced functions on the main set of monitors — hooked up via the DBox — from Cubase. Best of both worlds

[Forum Admin]

Best of both worlds

Yes, isn't it great we can do all this nowadays? I like the flexibility to work in different ways, and Studio One with my Studio 192 and a monitor controller - in tangent with iPad control via Studio One Remote or UC Surface apps allows this.

Look forward to reading your nOb review.

[Sam Spoons]

That sounds like the DFA knob on my desk......

[Forum Admin]

After Hugh's glowing review a while back and comments in this thread, I bought a Drawmer CMC2 monitor controller to use instead of my SM Pro M-Patch2.

It arrived today and I swapped them over, powered up the CMC2 and a veil of dullness was instantly removed from any mix I played through the CMC. It really is as transparent as Hugh stated in his review. There's a noticeable sheen at the top end on my Sceptre 8s that was lacking with the passive M-Patch2.

So, one happy bunny.

[jimjazzdad]

After Hugh's glowing review a while back and comments in this thread, I bought a Drawmer CMC2 monitor controller to use instead of my SM Pro M-Patch2.

It arrived today and I swapped them over, powered up the CMC2 and a veil of dullness was instantly removed from any mix I played through the CMC. It really is as transparent as Hugh stated in his review. There's a noticeable sheen at the top end on my Sceptre 8s that was lacking with the passive M-Patch2.

So, one happy bunny.

Its always great when you patch in a new piece of gear and notice a change for the better! But I can't help playing devil's advocate: when you see a "sheen" on the water it may be pretty, but it usually means something has been added to the water
Danish mastering engineer Holger Lagerfeldt has a pretty good video out about why he loves his passive monitor controller (albeit an expensive passive controller - the 2400 Audio Imperium): https://www.youtube.com/watch?v=5qrYl3Do9ec I think if one manages to keep sensitive to cable length and has good amplifiers with high impedance inputs, the whole high frequency loss thing goes away. One does lose a few dB of gain, but that's not usually an issue either. Passive works for me anyway. Can't comment on the M-Patch2 or the CMC2 as I have never had the pleasure of auditioning either.

Cheers!
Jim

[Hugh Robjohns]

It really is as transparent as Hugh stated in his review.

Phew!

H

[ef37a]

A HIGHER input impedance actually makes cable HF loss worse!

Dave.

[Hugh Robjohns]

But I can't help playing devil's advocate

Indeed!

There's nothing fundamentally 'wrong' with the concept of a passive controller -- it just comes down to the implementation and installation, same as it does with an active controller. It's all swings and roundabouts...

Danish mastering engineer Holger Lagerfeldt has a pretty good video out about why he loves his passive monitor controller

Looks well-designed... but some of his claims and graphs are a little misleading IMHO. The problems he highlighted in the active controllers either come down to poor implementation (like the mains hum artefacts), or are irrelevant and grossly misleading (like the D-A noise floor at -123dBu, which is bordering on technical perfection). And some of the shouty purists might get sniffy about the idea of all that sharp-edged digital control floating around next to the precious analogue!

I think if one manages to keep sensitive to cable length and has good amplifiers with high impedance inputs, the whole high frequency loss thing goes away.

Very low source output impedance is important too (and that can become a significant problem in a passive design at high volume attenuation), but yes, I agree that if the implementation and installation is done well it can work fine -- and I have been known to use a passive controller myself from time to time...

The use of switched attenuators make the biggest difference in performance terms IMHO -- although the Drawmer design uses a clever four-gang pot to improve stereo tracking compared to most standard designs.

H