audio standards at low V+

The audio has to be 'padded down' before conversion and amplified after the DAC.

Adopting lower working voltage levels would result in poorer noise performance in particular.

Graham

First of all, audio has gone digital long time ago. The only place where we still find analog circuitry is the very front-end and in less and less amount in power amps for loudspeakers/headphones. All the sound processing, mixing and registration/masterization is exclusivly done in the digital domain. And that is where the headroom was needed. Imagine 16 mikes on the drums, not unusual. which are mixed down to 2 tracks. Now a kick on the bass-drum would reach all the mikes and cause an output voltage several times of that one on the kick mike alone. If you have levelled the single mikes in "solo" to 0dB O/P, your 18dB headroom is eaten up and in fact you would get hard limiting. This scenario is the nightmare for a life recording engineer. Today we have it easier. Each mike is digitized and a double precision float gives you not only 18dB but 94dB of headroom or even more. No need to insert filters screwing up the low frequency phase or limiters where still a short overload would occurr.

What is digitized are the mikes, having a typical sensitivity of 10mV/Pa. A loud snare hit closely miked would maybe reach 130dBpeak, which is +36dB higher and corresponds to 630mV. So a 24bit A/D converter with 5Vpp input range can perfectly well digitize this signal with still 9dB headroom and over 20bits of resolution, a far higher S/N than those analog days. In fact you do not need any gain stages any more, mikes have -10dB pads in these apps. Then all processing is done in DSPs working with now 0.8 to 1.25V core voltage, but that is irrelevant. So please do not mix up cellphones with pro-audio. We use never less than

5Vpp input range for this type of application and it is sufficient and far better than even the best old analog circuitry. BTW even this stage will be disappearing soon, with directly digitizing mikes and keyboards with firewire outputs.

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ciao Ban
Bordighera, Italy

What a load of rubbish.

More complete rubbish.

You obviously have zero experience in pro audio. Try getting some facts straight before pontificating.

Ian

The good old days, when the dynamic range of audio was limiting the sound engineer's whims...

These days the dynamic range of many audio tracks is so wide that I find myself constantly fiddling with the volume control for comfortable listening.

I've even stopped going to the cinema because of that. At one moment the sound can be so loud it's painful, and the next you can't hear what's being said under the noise of the fellow behind crunching his pop-corn. It takes away all the pleasure, at least for me.

More dynamic range is *not* always better.

Jeroen Belleman

Hey Ian, you must be one of those Audiophools.

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ciao Ban
Apricale, Italy

You are right, the end product will sometimes sound much better with only 50 or 60dB of dynamics, just what the black records have. But it is *not* the situation of the life act. Imagine a symphony orchestra from ppp to ffff. It can not be captured this way, but in a noisy environment(car or cinema) a compressor might add more transparacy. Depends on your listening conditions. Since it is easy to compress the dynamic range, you can use a AGC circuit. I live in a *very quiet* environment(except in the morning when the birds are singing) and enjoy the full dynamic range with my speakers.

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ciao Ban
Apricale, Italy

Not true. A lot of analogue outboard equipment is still used.

Not true. A lot of audio is mastered to half inch tape.

Not true, with 16 mics on a kit they will all be closed miced (except for the overheads.) The signal from the kick mike will be at least 40dB greater than from any of the other mics. The sum of all the sound of the kick on all the other mics will be no more than 12dB higher than from one mic, so together they will be 28dB below that of the kick drum mic and will not compromise your headroom in any way.

More rubbish. First the headroom is not needed (see above) and the noise floor not the headroom is the limiting factor anyway.

More rubbish. The s/n ratio is not determined by the resolution of any a/d convertor but by the analog front end electronics.

You never did need gain sages in these apps and 10dB pads have been around for decades.

Now you really show your ignorance. 5Vpp corresponds to about +7dBu. The theoretical noise floor of a 24 bit converter is about 144dB below this i.e about -136dBu. Unfortunately, the noise floor of even the best 24 bit A/D converters available today is only in the region of -97dBu giving an achieved s/n of a mere 104dB. The best analog recording consoles have an output noise of around -90dBu and a max output of +26dBu giving a potential s/n of 116dB - rather better than the best current digital.

Perhaps it is you that is the audiophool.

Ian

may I recommend you read this

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ciao Ban
Apricale, Italy

I worked here

and there is no more analog equipment used, exept when a musician insists. BTW that photo is me, not Conny

May I laugh, how many 1/2 inch mastertapes exist? In the 70ties we used only

1/4" 2track mastertapes(Ampex Grandmaster).

Have you ever worked in a Studio? The problem is, that you use the -18dB pad on the kick and you amp the overheads. what counts is the SPL that reaches the mikes.

Good mikes can bring more than 130dB dynamics, Look at the Neumann/Sennheiser range of products. With close miking you are way above the noise floor.

You need straight wire, and go directly into the A/D

If you amplify the mikes to be used in an analog mixer, you will need some

16 to 20dB gain, since you want to use the full possibility of the mixer. All the sends and inserts allow a maximum level of +24dBu and not a single mike is able to put out this level.

Do not forget that we work with balanced signals, where with the same supply voltage we can have 6dB more level.

I'm sorry, but you do not seem to have any experience with what you are saying.

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ciao Ban
Apricale, Italy

Utter nonsense. Not least since the cost alone of a meaningful control surface for a DSP mixer costs more than a simple analogue mixer outright.

That's not entirely strictly true actually. For various practical reasons.

No. It doesn't. See the inverse square law. Most stuff of that ilk is close miked and may also be gated so pickup on other mikes should be reasonably low. If the 'crosstalk' was that bad it would never be possible to mix a record meaningfully.

More rubbish.

All the 'converter boxes' for DSP mixers have internal mic preamps.

Graham

Fascinating. And the don't use 5V A/Ds. So what is your point.

Ian

Good so you agree with me.

Laugh as much as you like, There are still plenty of half inch masters made.

SPL is what I talking about. You obviously need some basic audio theoty.

I agree. But they are the exception and not everything is close miced.

More incomprehensible rubbish.

Showing your technical ignorance one again.

What makes you say that? Do you dispute my technical arguments no? I worked for Neve in the 70s designing mixers and I run a recording studio to this day. I have plenty of experience in this topic. It seems you are unable to cope when someone exposes your lack of technical knowledge.

Ian

You are talking about semi-pro scene. We got our first digital mixer in the early 80s.

But for what reason do we then need the "headroom" actually?

You are right, to do any meaningful mixing you should pickup a band with only one stereo mike. We did that with almost all ECM recordings, which are praised in the HiFi scene. But many bands have to overdub because of missing skills or because of non contemporary recording sessions with all the musicians. Now the latest trend is to remove the x-talk digitally with adaptive filters.

I gave the Neumann link in another post. D1, these are the mikes we are using now.

With 140dB dynamic range for shorted input and 130dB with capsule attached. Gain is done in the digital domain only with these state-of-the-art mikes.

The guy was asking for new emerging standards, not how it was done last century. And I tried to show the future way as I see it, working for a top-edge audio company. Maybe I'm wrong and we come back to opamps or tubes.

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ciao Ban
Apricale, Italy

We had an MCI 1/2 inch 2 track in one studio I worked, it sounded pretty solid, and with 456 driven hard as well. But 1/2 were pretty rare. Most stuff was on 1/4". AFAIR when working with Bauch (Studer/Neumann distro in the UK) there were not many sales of A80

1/2" headblocks compared to 1/4" blocks

martin

Half inch mastering is surprisingly common. Look here:

and here:

and here:

to name but three.

Ian

I couldn't find any credits to your studio, maybe you could provide a link. Also I phoned some old friends from Neve, but nobody seem to know you. Did you change your name?

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ciao Ban
Apricale, Italy

Yeah I love the idea of 1/2" 2tr, but I would hazard a guess that there are, worldwide, less than 1000 1/2" 2tr alive today ( nope not going to google it)

martin

I did. My real name is Ian Thompson-Bell. Ask them again, they'll remember me.

Ian

Last line: did you really mean 'band', or have you recorded more than one?

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~ Adrian Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk