Preamp comparison in SOS October 2012: your views!

[Sam Inglis]

Hello,

In October's issue of Sound On Sound we tried to cut through some of the hype surrounding mic preamps, to find out how much of a difference they really made in one particular real-world recording situation: tracking a grand piano. Jonathan Dodd of Realpiano was kind enough to let us use his Yamaha Disklavier, which can reproduce the same performance from a MIDI file with uncanny accuracy. Session pianist Matt Cooper created a short MIDI piece that gave the piano a full workout, and we recorded it... over and over again!

We used three different mic setups: a pair of Brauner cardioid valve mics, a pair of Sennheiser MKH20 omni small-diaphragm capacitor mics, and a Royer SF12 passive stereo ribbon mic. These were recorded in turn through eight different preamps, representing a wide range of design approaches, from the preamps in a budget mixer to a valve preamp costing over £2000. Subscribers can read the full article here, and the audio files are available for everyone to download here. The catch is that I've removed any reference to which preamp is which from the names of the files...

...so, how much of a difference can you discern between the preamps, and can you guess which preamp is which? The key will be revealed in due course, but as a quick reminder, the eight preamps featured were:

AMS Neve 1073LB
API 3124+
ART Pro MPA II
GP Electronics PML 200E
Mackie 1402 VLZ Pro MkII
Maselec MMA-4XR
Prism Sound Orpheus
SSL XLogic VHD Pre

These are referred to (not in the above order) by the letters A to H in the audio examples.

We're very curious to hear SOS readers' opinions!

[tiberius]

I'm quite curious to find out which is which, I could do with a second preamp and I hope that
I prefer one of the cheaper preamps.

However the more I listen to them the more confusing it gets so I've just listened to the
first section to keep it simple.

Favourite
(A) Smooth 'tubey' top end.
(H) Sounds more stereo than others?
(E) Clean accurate, neutral and smooth.
(D) Good not much character. is this cheap?
(B) Classy vintage sound. is this expensive?
(G) Clean accurate neutral
(C) Vague/dreamy mids
(F) Dark
To Least Favourite

Listening to the next microphone section somewhat changes the ratings,
so I guess I'm just rating the combination of Brauner and pre.

[AndersM]

Having only listened to the SF12 variations so far. To be perfectly honest, this kind of makes me want to send back my semi-expensive preamps to the dealer... The differences between these preamps are -from what I can hear, totally negligible for the type of (pop) productions I am involved with.

Maybe a little difference does add up once you start piling tracks on top of each other, but unless someone convinces me otherwise, I'm inclined to think I'd be just as good off with my standard interface preamps for that floor tom at the back of the mix.

[James Perrett]

When I started recording, just about everyone used the preamps in the desk and just got on with it. A few people, mainly American, talked about using different preamps but most engineers didn't think that the small difference between properly designed preamps was worth the effort. Mic choice and positioning is still far more important than preamp choice but I guess the marketing people have taken over now and confused everyone.

James.

[Richie Royale]

Interesting, I'll have a listen later, not that I really use pre-amps in my music, but it will be interesting nonetheless.

[Hugh Robjohns]

It was a very interesting test to do -- and finding the Disklavier was the key to making this work as we could think of no other way of ensureing reliably repeatable performances for each mic/preamp combination.

When we were listening back to the recordings -- in full knowledge of what preamp was in use -- we were convinced we could percieve significant differences. But when the recordings are anonimised it is actually remarkably difficult to accurately identify each preamp!

We specifically chose to challenge the preamps with low output ribbons and high output capacitor mics, and to use a wide dynamic range source... but we didn't try deliberately 'pushing' the preamps to force preamp character that way -- these were all essentially purist recordings and, as you can plainly hear, even the cheapest modern preamps manage to deliver a perfectly usable sound that is pretty accurate and uncoloured.

James is quite right when he says mic choice and positioning are far more critical in terms of sound quality and character... although I think the better preamps still do manage to capture or deliver something that is subtly preferable given a choice.

H

[Mike Senior]

Fascinating one this! Like Hugh I felt that all the preamps put in a usable performance -- certainly from a mixability perspective within a normal commercial production context.

That said, I probably wouldn't choose preamps F (slightly 'plasticky' somehow), C (felt a touch boxy tonally), and B (too strident in the midrange) based on these files, and my opinion was that A, D, and E gave the clearest presentation across all the mics. G and H were also alright, but the former rather muffled at the high end, while the latter seemed to be the opposite in that it seemed a little zingy. To use the most scientific of terms...

But I'm almost positive I couldn't reliably tell which one I was listening to in a blind test.

[Martin Walker]

This is a fascinating test, particularly since I'm currently evaluating a range of Nebula 3 character preamp presets for a forthcoming SOS review that include an API and ART tube models. It also echos my views (already mentioned by Frank) that mic, mic placement and acoustic treatment choices are all mroe important that any tonal difference between preamps.

Thanks for putting in all the effort guys, although I suspect a few people may consider that 96kHz files might demonstrate any tonal differences more clearly!

OK – on a fairly brief listen I'll throw in my two pennorth.

I forgot to mention one thing... The letters are NOT the same for each set of mics. In other words preamp A for the Brauners is not the same as preamp A for the Sennheisers or Royers. Apologies for the confusion - I thought it would be best to change the order each time as that can have quite an influence on one's perceptions.

DOH!!

Here are my original notes for all three separately then

Brauner

A nuetral and rich - NICE!
B slighty veiled at top end, otherwise rich mids and low end
C slightly harsh midrange
D bigger bottom end NICE!
E clearer, more transparent NICE!
F close & intimate
G slightly distant
H closed in

MKH

A no particular sound
B intimate, can hear further in NICE!
C slightly hard midrange
D nuetral
E intimate
F warm, close and detailed
G warm and intimate
H rich mids

Royer

A less detailed
B shrill top notes
C warmer bottom end
D delicate, intimate
E less detailed
F detailed yet nuetral, with midrange richness - NICE!
G less detailed
H shrill & slightly harsh

Your mileage may vary

Martin

[DVallet]

Hi,

Nice test !

The first thing I could say is that differences are really really subtle ...

But I'll go for the E !

[Richie Royale]

H is the most obviously different over all the mics. I've only had a quick listen but it stands out against the others; something veiled or murky about it makes the low end a bit more prominent.

What is the piston like noise? Is it the mechanism playing the keys?

The most obvious thing is the difference between the mics, which sound quite different, but both nice. I think the Royer would be mice choice, but I've not listened properly yet.

[mjfe2]

I need to listen properly to work out an order of preference but they only one that made me sit up was E. Great clarity.

I noticed the loudest part of the track clips briefly....was this intentional so we could hear the preamps pushed to their limit?!

[Sam Inglis]

I forgot to mention one thing... The letters are NOT the same for each set of mics. In other words preamp A for the Brauners is not the same as preamp A for the Sennheisers or Royers. Apologies for the confusion - I thought it would be best to change the order each time as that can have quite an influence on one's perceptions.

[mjfe2]

I forgot to mention one thing... The letters are NOT the same for each set of mics. In other words preamp A for the Brauners is not the same as preamp A for the Sennheisers or Royers. Apologies for the confusion - I thought it would be best to change the order each time as that can have quite an influence on one's perceptions.

Ha, good idea. In which case, I meant that E in the MKH20 lineup stood out for me!

[Sam Inglis]

I noticed the loudest part of the track clips briefly....was this intentional so we could hear the preamps pushed to their limit?!

No! It was a boo-boo. I thought we were recording a bit hot, but at the time we didn't spot it on playback so I let it go. There's also a problem with the Brauner H file which has just been pointed out to me. I'll fix that on Monday.

[gennaroschiano]

interesting article. Preamp examples are pretty hard to pick apart from each other. I tended to prefer D, E and H and only really had an issue with C which sounded a little thin to me. On another type of source (horn etc)... I might prefer A which sounded especially roasty. (For the Brauner comparison)

[Mike Senior]

I forgot to mention one thing... The letters are NOT the same for each set of mics.

I'd assumed they were -- I'll have to have another listen! My comments above were mostly based on the Brauners, though. Still, the fact that I didn't notice illustrates how little I can reliably identify which preamp is which!

[tiberius]

Ah that explains a lot. I thought I'd need a different preamp for each microphone...

[Hugh Robjohns]

Hmmm... I think the point is already proven: while there are subtle differences between preamps, they really are very, very, very subtle and not terribly significant in the grand scheme of things for most situations. If you like to push the preamp for deliberate colouration, of need unusually high gain for distant ribbons the differences might become more important. But in general, modern preamps are all remarkably good -- even many cheap ones!

H

[Hugh Robjohns]

I noticed the loudest part of the track clips briefly....was this intentional so we could hear the preamps pushed to their limit?!

No, not intentional at all -- it was an annoying faux pas. Our host was 'old school' and liked to work with negligible headroom... And was caught out on occasion. The large number of permutations we had to work through and the limited time meant we weren't able to audition all the playbacks and repeat takes. Profuse apologies -- but I don't think it detracts too much from the aim of the comparisons.

H

[mjfe2]

I noticed the loudest part of the track clips briefly....was this intentional so we could hear the preamps pushed to their limit?!

No, not intentional at all -- it was an annoying faux pas. Our host was 'old school' and liked to work with negligible headroom... And was caught out on occasion. The large number of permutations we had to work through and the limited time meant we weren't able to audition all the playbacks and repeat takes. Profuse apologies -- but I don't think it detracts too much from the aim of the comparisons.

No worries, it hasn't detracted from what is a great comparison. As for 'old school', if only people appreciated that old school is really leaving 20dB or so of headroom! If only everyone read this: http://www.soundonsound.com/sos/sep10/a ... 0910-1.htm

[dmills]

Not really an unexpected result, as you say, anything reasonable is usually not going to be the weak link.
Preamp choice is as much about studio marketing as sound engineering, the client wants a U87 with an Avalon preamp, fine, that is what hire is for, will it make a difference, probably not on a technical level, but if they are happy, odds are I will get a better take.

I do notice however that the SF12 is the only mic in the test that lacks an active output stage, all the others have the impedance converter in the mic (which is effectively the first stage of the preamp), it might be that throwing an SM57 or RE20 or something in there would have been rather more revealing of any differences that were there?

Given that for me this test is as close to a null result as makes no difference, I am just wondering if some of the claimed 'major' differences between preamps might be down to preamp/mic interaction, which will surely be reduced substantially by using mics with built in power gain.
Some of it is clearly differences in clipping behaviour, and most of it is probably marketing bulshytt aided by a healthy dose of nobody calling the emperor out for public nudity, but I just thought I would flag up the (quite reasonable) limitation of the study.

Regards, Dan.

[Exalted Wombat]

Yes, it does seem as if you avoided testing microphones that MIGHT have responded differently with different preamps. Whether it would take anything more than a suitable shunt resistor to level the field is another question!

[dmills]

Yea, going there is a combinatorial explosion however, and it is not even clear that there is a meaningful effect there to be found.

Regards, Dan.

[Airfix]

this is a lovely example of the craft - the craft of capturing audio properly. Mics and mic placement - rooms are gifts or curses. Good ears know the difference. Some of us have 'it' some of us dont.