Preamp section for active monitors?

B

Bigus Dickus

New member
After some research, and on the advice of members here, I've purchased a pair of Yorkville YSMP1's (other thread just below).

In that thread, an interesting quesiton came up. I had asked if active monitors have a gain (volume knob), and someone replied that most active monitors have a gain control on the back. That would mean that there is a preamp section before the amp section in those monitors.

Someone else replied saying that wasn't correct, and that for most active monitors you either use the gain control on the mixer they are connected to, or for PC based systems you use the master level control in the computer.

If that is true, then for PC based systems is the level set digitally or in analog? In my specific case, the soundcard is a Delta Dio 2496, with 24 bit D/A converters and analog output identical to the Audiophile (two channels at least). I've read all the info I could find about my card, and there is nothing to suggest that it has an analog gain in the preamp section. In fact, I don't get anything suggesting it has a preamp section at all.

I was under the impression that these soundcards output a line level, just like a CD player would, and that a preamp is needed to adjust gain before power amplification. My manual says that maximum "gain" in the master level setting is 0db, and you can attenuate from there. I can't help but think this attenuation is done digitally.

If the master level is a digital volume control, then isn't that, well... bad? I mean, you're going through a lot of trouble to set levels in the mix, and so forth, and having the digital signal altered in the final stage before output would seem extremely counter-productive. If this is what actually happens, and the Yorkville's indeed have no gain adjustment, then purchasing a stereo preamp would seem to be in order.

Or, is it possible that the master level is actually adjusting the output voltage in the analog section of the card, and leaving the digital signal at full scale? This sounds pretty confusing to me. I can't imagine why you would adjust volume digitally after all the hard work in mixing/mastering, but I see nothing to suggest otherwise.
 
Event TR5s

These have what Event calls a "sensitivity" control that, when shipped, was turned all the way up. The materials explain (sort of) the idea:

This control is used to compensate for different signal levels that appear at the input. The control has a 20 dB range; when set at maximum (MAX), 0.5V RMS input at the balanced ins or 0.25V RMS at the unbalanced in will produce full amplifier output.
Click to expand...

It's used to limit distortion in really hot signals, I guess. The units are pretty new; so far they sound fantastic.
 
Anyone else have any comments on this? I know not everyone on the board is using a mixer that gives them gain control in analog... many/most are probably running straight from soundcard into active monitors.

Doesn't it seem "wrong" to digitally scale the output as the last step when much of your mixing work is in setting the appropriate digital "scale" (level) in the first place? For one, you're chopping off some dynamic range by adjusting gain digitally, changing the noise floor, possible changing the effects of dither at low volume levels, etc...
 
The "gain" knob on those active monitors are much like the "gain" knob on the input of a power amplifier. Use IT instead of the software mixers output to adjust your monitor volume.

Sorry, that is all the time I have right now to explain. :)

Ed
 
I was refering to ACTIVE monitors. They have the amplifiers built into the monitors, and there is no volume control on them. That way you have to control the volume from the source. Either with the faders on a mixing board, or if your running directly from a soundcard, the master volume control from windows (or mac).

If you have Passive monitors, you need to buy an amplifier for them, and then the control for the volume would be on the amplifier. But look into the amplifiers a little bit, personally im going to get actives when i get the money, because then i don't have to deal with finding a suitable amplifier. Besides the actives have amps very closely matched to the speakers for the highest performance.
If im not mistaken you can't just use any old home stereo reciever, you have to buy a special type of amplifier for them.
 
ok, so you're saying active monitors have no gain control, and sonusman is saying they do.

I guess I'll know myself tomorrow. :) I do know that adjusting gain through windows is the last thing I would want to do. Scaling digitally after all the hard work setting levels and such correctly...
 
Did you order the Active YSM1P's?
Or the passives?
models YSM1, YSM1i are passive, they require a seperate amplifier for power. The only active model is the YSM1p's.

If you ordered passives then you have to buy a seperate amplifier, and the volume control will be on it.

I was told that Active monitors have no volume controls on them what so ever. Some have dip switches to help with placement and the effects of being in a corner, or in a wall.

http://www.yorkville.com/default.asp?section=3

i just checked the website and it says nothing about a volume control in the specifications. It mentions an Input Trim (+9/-6dB), but thats it.

You have to adjust the volume at the source i think. So if you had it running through a mixing board, you would use the faders for the output to adjust the volume, and if you had it in a computer, you'd use the computers output volume to adjust it.

This is what ive been told before by several people on this board, and what i've just read on the website.

I could be wrong, i could have been mistaken. But thats what i've been told/read. Anyone feel free to correct me because i plan on buying a set of the YSMIp actives soon, so i will need to know this.
 
Wait, know i know for a fact that they have no volume knob.

They operate seperatly from each other. They aren't like computer speakers where a volume knob on one will affect all speakers. They have their own amplifiers if they are powered, and they are not connected.

Therefore if they had volume knobs, they would both have to have volume knobs, and they would operate independantly from each other, and you'd manually have to try and match the volume of each one to each other.

You can buy them seperatly, well with some monitors that is. You can buy one, or you can buy two, they aren't always sold in pairs. So they aren't linked together in any way.

Now that makes sense in my mind but once again it could be wrong.
 
Yes, I ordered the YSM1P's.

Perhaps some people are referring to the input trim as a gain adjustment... they're really the same thing, just that input trim's usually have less adjustment and don't aren't necessarily set up to take a line level input.

Adjusting the volume digitally sounds like a crappy way to do things. I'll probably look for a used stereo preamp on ebay or something.
 
you don't want a preamp though. it will effect the sound and ruin the prupose of having flat speakers. maybe get a small mixer or something to control the volume from. that is what i have, a mixer to control the volume. and i don't think that controlling the volume from your PC should be a problem.
 
What? Why is a mixer more "flat" than a good preamp? If anything, a stereo preamp should be of better quality for the money since it is simpler. I'm not talking about a fancy dolby digital preamp or anything like that, just a good, solid, old school stereo analog preamp. If it isn't a POS, then it should not add any coloration to the sound... no more than a mixer does anyway.

And I still think using digital volume control is not a good idea. Suppose you add dither during mastering to eliminate the harshness of a low level signal fading into silence. You then turn the volume down a bit, which digitally scales the signal, and completely changes the point at which the dither starts to have an effect. For that matter, if you had the volume scaled down digitally, you might not even realize you needed dither in the first place.

Just an example, I'm sure there are numerous instances where altering the signal digitally would mask or alter the change you are contemplating making.
 
I'm probably wrong, but i never thought of my mixer as a preamp. I have the soundcard sending the loudest possible signal to the mixer, and then i let the volume i need through (the mixer) to the speakers. Am i boosting signal? I didn't think so... Then again i get confused with these things and I am probably missing a very important piece of info :)
 
yea the mixer won't boost the signal, you just want to put the signal through it, so you have the use of the faders as a volume control. The speakers have amplifiers built into it, so amplifiing the singal twice, by two different amplifiers would be very very bad! ALSO, if you bought a small mixer like a mackie 120vlz pro, or a small soundcraft m 8, you would have the use of some faders for volume control, plus some very usable preamps for your microphones. Im planning on buying these speakers ASAP and i totaly agree that having to control the volume through windows, and the possibility that the volume may reset to 100 percent after restarting or running another program (which happens very frequently to me) is totaly unacceptable. Its ok with these computer speakers because the volume control is on the speakers, and if it goes from 50%-100% it doesn't make a huge difference, but with the monitors if you have them at 30% then they jump to 100% you may just die, or they might just die!

It is possible but not very desirable. I'll have to deal with it until i can afford a mixer, or maybe i'll just rent a mixer for a while until i can buy one.
 
Some powered speakers have volume knobs. Here is where it gets tricky. They don't boost the volume, they passively attenuate it. The same way a power amp's volume knob works. That is what Ed didn't have time to explain.

The knob only CUTS the volume from the maximum of 0 or BALLS OUT LOUD.
 
Refer to my post above

The Event TR5s are active monitors, each with two amplifiers producing a total of about 100 watts per speaker cabinet. They each have a sensitivity control - "attenuation" if you will.

I expect it is exactly as TexRoadkill suggested. Turning down (or up) the gain would not color anything if it your only option is to cut signal or elect not to cut.
 
so you would control the volume from there? Or just for fine tuning?
Or would you control the volume from the source, such as a mixer or computer?

I'm not clear on this anymore and i'll most likely need to know this.
 
A few notes, from what little of this I understand:

Most active monitors are analog. They take a line level signal and produce sound. Obviously, along the way they must be amplifying the signal (a line level signal doesn't have anywhere near the power necessary to produce a loud sound, no matter how efficient the speaker is). They do other things too, though. Most obviously: there's a crossover in there! There may well be (ordinarily would be) more than one stage of amplification. The first stage (call it a preamplifier, if you want) might have variable gain (perhaps by controlling the amount of negative feedback in an op amp). A pot with a label called "gain" suggests that the pot does just that. Alternatively, all the gain stages might have fixed gain. If so, there might be no control over levels at all, or maybe there's a variable attenuator. A pot with a label called "trim" suggests that the pot does that. But the labels may not always be used quite this precisely.

I suspect that most active monitors do have some sort of level control, whether it's active (controls gain in initial gain stage) or passive (attenuates incoming signal), but maybe some don't. Yes, there may well be (probably are) two separate controls, one on each speaker. Yes, they must be manually adjusted so that they match. This isn't a big problem: you adjust them so a "nominal" level on the monitor output pot on your mixer produces a nice listening level, then you adjust volume as needed with the monitor output pot.

As to whether the presence of a gain pot controlling the initial gain stage makes the initial gain stage a "preamplifier," I don't have a clear view. Generally, I'd think of a "preamplifier," in this context, as something that has some other controls, like the tone controls in the preamplifier section of a home stereo amp.

I agree that (or at least it seems to me that) the preferable way to adjust monitoring level would be at the analog amplifiers, not by scaling the digital signal down before a digital-to-analog conversion. But this gets beyond my knowledge. That would be consistent with the standard basic-computer set up, where there's a single volume control (analog, I presume) on the front of the little satellite speakers. I guess if I were running a computer soundcard straight out to active "studio" monitors, I'd probably want a single-pot level control somewhere in close reach, rather than the two separate pots on the back of the monitors. You could use the preamp section of a home stereo. For that matter, you could use an RNC, with the compressor set to bypass.

I gather there are some active monitors that take a digital input: that is, they have their own digital-analog converter built into them. How they implement a gain control, I don't know. I suppose it might be a digital level control before the DA converter (followed by a fixed gain amplifier). I'd tend to think it's not, but I don't know.

Incidentally, a mixer has lots of op amps in it (all those little triangles in a schematic diagram), which might do any of a number of things, not all of which involve actually amplifying a signal level. I would expect that there's an op amp just before the monitor output, the gain of which is controlled by the "monitor level" pot on the mixer. Between the source (soundcard, tape deck or whatever) and sound coming out of a speaker, your signal may have run through quite a few different op amps.
 
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Analog signals are cool.

As a practical matter, any signal I will be hearing with my setup is going to be analog from the box on out. So I treat it as an analog signal. I have multiple sources going into any of three monitor sets; a Bose stereo, a pair of active studio monitors, and an active subwoofer. Stereo line signals in can come from a stereo, a CD player or a balanced set of lines from the multitracker. Because it's all analog, I use a baby Behringer mixer as a simple monitor patch bay (best $60 I've spent lately) with a balanced line out to each of the Event monitors and an RCA line out to a subwoofer.

I have the Events cranked up to max and attenuate the signal at the mixer. The subwoofer is set to intecept at a high frequency but is not cranked at all - just a touch. That's also attenuated at the mixer. The Bose system has a stereo aux input, so it can take line signals from the mixer and play "monitor," but also can dump a stereo line signal into it. So I get a stereo system (on steroids) out of the deal as well.

This allows me to take a signal from any source and hear it on any speaker set, or combination, depending on what I'm after.
 
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