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[Barry Hufker]

I'm sure Andy has much he'd like to add but as he is traveling, I'll say the little bit I know.

I contacted Andy some weeks ago about the new microphones after hearing his sound samples.  I experimented with the Model As and enjoyed them enough to be his first customer, purchasing a pair.

I find the microphones to be low distortion, very clear (with fine stereo imaging) and smooth (Andy can explain further).  I don't have an A/B comparison sample for anyone to hear but I regularly use Sonodore RCM 402s.  I employed the Model As for recording an a capella chorus.  I was (and am) quite pleased with the recording's clarity and detail.  As with all new equipment (for me anyway) the new microphones take a while to understand and use.  But once in hand, are certainly worthwhile.  I now have to re-evaluate the Sonodores in light of the Model As.

More than this I can't add and will leave the rest to Andy to explain.  After all this is his baby.

Barry

[Andy Simpson]

Peter,

Your posts seem to have disappeared before I had a chance to answer further.

Regarding ultrasonic microphones, it is well known that both parabolic-reflector and horn-loaded principles have been applied in ultrasonics.

However, as far as I am aware, these were applied for reasons of either basic gain or directivity or both - not for reasons of improving diaphragm stability (damping).

I hope you will appreciate the difference between these ultrasonic implementations and my implementation within the audible band.

Anyway, I will be in the UK for a couple of weeks and would be happy to visit oxford if you are interested to discuss (PM if so).

Best regards,

Andy

[J.J. Blair]

Andy, what is the manner of transduction?  Condenser?  Moving coil?

Was the show a success for you?

[Andy Simpson]

Some replies to other questions (in no particular order).

The wood (beech) - this was chosen for fine tolerances of machining, warp stress, acoustic 'deadness' (in resonance terms) and basic mass.

It is made in several pieces for the simple reason that making the piece from a large section of wood would be quite uneconomical. Possibly, this sectional arrangement could affect a reduction in transmission of resonance of the wood itself but at normal SPLs, self resonance of the microphone is as insignificant as in any other microphone.
There is little parallel with woods as applied to musical instruments.

The diaphragm itself is moving coil for several reasons.

Firstly, the operating principle suits horn-loading.

Secondly, the operating principle & response provides ideal match for the acoustic horn.

Thirdly and perhaps most significantly, this is the most simple circuit in electronic terms (ie. coil & transformer), so there is nowhere for electrical time-domain distortion - ie. no gain stage or other electronics which can produce time-domain distortion in the circuit.
(This does preclude optimal microphone pre-amp input impedance for electrical damping - somewhere around 1-2k ohm is fine).

There is one final aspect to the design & implementation which offers interesting validation of the concept:

The microphone is designed to be post-equalised.

This means that using a simple equalisation 'curve' the mic is brought to 'flat'.

This is self-validating in that the first principle of design was this:

If time-domain is captured cleanly, the frequency domain can be brought to 'flat' with equalisation - and that the equalisation will be utterly 'transparent'.

This is the single most significant concept regarding time-domain performance.

Those of us who have eq'd ribbon microphones will have experienced something similar but on a smaller scale.

Best regards,

Andy

[Andy Simpson]

J.J. Blair wrote on Mon, 29 October 2007 20:40

Andy, what is the manner of transduction?  Condenser?  Moving coil? Was the show a success for you?

JJ, - see my post above (written probably while you posted).

The show was great fun. I took 1k of horn-loaded monitors and made an orchestra appear at SPL! (and more impressively, also a tambourine).

Also, I demonstrated what ~30dB crest-factors sound like with an RMS SPL of around 90dB!

Best regards,

Andy

[J.J. Blair]

I'm glad the show went well.  

Congrats, and good luck with your venture.

Maybe you should send a set to Brad Lunde at Transaudio to see if he;s interested in distributing it.  He is a person that I think very, very highly of, and his company is first class all the way.

[panman]

Andy, sounds really intresting! If got it right, the diaphragm, moving coil and the trafo are forming so to say one unit?
This post-eq makes sense, in fact, it is almost a must in recording individual steelpans decently. However, I only roll off frequencies to avoid well known problems. You mentioned "electrical damping", so I gather you meant roll-off?
You also refer to "eq`d ribbons", but eq`d on a smaller scale, so your mics need a heavier eq? My guess is that there is probably only one major hump in the curve not to cause too much trouble using
one and the same eq.
Best regards,
            Esa

[Andy Simpson]

teleric wrote on Sat, 27 October 2007 19:54

Any comments on the sound clips? I thought the orchestral sounds rather nice but very strange sounding, mostly because of the position of instruments (strings left, brass right). then i heard the first pop sample, i thought the sound was again very nice, but i have difficulty imagining a single mic getting all this. A bit dark also?

Sorry, I missed this one until just now.

The pop samples were made in overdub stages with a single mic, ie. one mic for drums, same mic for guitar, amp, tamb, vocals, etc.

Actually, the overdubs were recorded 'live' to studio monitors at realistic SPL (you can hear this if you isolate left or right channels). One of the useful properties of cardioid pickup.

Best regards,

Andy

[maxdimario]

Interesting Andy!
Did you know EMI made a microphone (the 'EMI moving-coil microphone') with a 2.5mm balsa-wood diaphragm?

It also required an EQ circuit to be flat. But I understand you coupled the diaphragm to a horn? That's great.

What is the output of the mic?

[Andy Simpson]

Do you mean sensitivity? From basic test, ~-40dBV/pa at 1k.

A balsa wood diaphragm?! Those crazy EMI fellows....

Best regards,

Andy

[duckhunter]

I am pretty darn impressed with what I'm hearing on those samples.  And whoever played those pop songs were heavily influenced by the Beatles and did a great job.  I admit that when I first saw the pictures I thought they were nothing more than a 57 stuck in a megaphone.  It would be nice to hear a sample of a rock group, though, to get a wider perspective.  I can see them now on stage at the grand old opry.

[J.J. Blair]

Andy, my friend ... please, please, please hire a professional drummer and redo those overhead samples!

[Barry Hufker]

I am proud to say I am one of the early purchasers of Andy's Model A microphone.  I have a pair of them and believe them to be fantastic.

Being a new design and a new philosophy/concept, they take a bit of getting used to, but they are marvelous.  The sample of organ and choir is my recording.  Today I just sent him samples of classical acoustic guitar.  The Model A's clarity, detail and lack of distortion are superb.

I have no business affiliation with Andy.  I consider him a friend and I am his customer but my remarks are made as an audio professional.

[Andy Simpson]

J.J. Blair wrote on Fri, 15 August 2008 19:59

Andy, my friend ... please, please, please hire a professional drummer and redo those overhead samples!

JJ - you have a '65 Ludwig (or was it Gretsch?) kit don't you?

Maybe I'll lend you a pair of mics and you can get me some nicer samples....

Andy

[Andy Simpson]

Barry Hufker wrote on Fri, 15 August 2008 22:26

I am proud to say I am one of the early purchasers of Andy's Model A microphone.  I have a pair of them and believe them to be fantastic. Being a new design and a new philosophy/concept, they take a bit of getting used to, but they are marvelous.  The sample of organ and choir is my recording.  Today I just sent him samples of classical acoustic guitar.  The Model A's clarity, detail and lack of distortion are superb. I have no business affiliation with Andy.  I consider him a friend and I am his customer but my remarks are made as an audio professional.

What Barry means by 'early purchaser' is that he has been through a hell of a learning curve.

In fact, I'm considering giving him a chapter in the revised user-guide....

Andy

PS - Barry, those guitar tracks are superb!