Gain Staging

[Nick_1234]

Hello,

Not sure if this is the spot for it, but if not please point me in the right direction.

When playing an iPod through an 1/8" jack is there an optimum level to have the Ipod volume at? Most locations are schools, with in ceiling speakers.

If the Ipod is set at max, wouldn't that send too hot of a signal into the amplifier? In turn doesn't that have a higher possibility to distort the amplifier?

Thanks!
N

[hbphotoav]

Originally Posted by Nick_1234

Hello,

Not sure if this is the spot for it, but if not please point me in the right direction.

When playing an iPod through an 1/8" jack is there an optimum level to have the Ipod volume at? Most locations are schools, with in ceiling speakers.

If the Ipod is set at max, wouldn't that send too hot of a signal into the amplifier? In turn doesn't that have a higher possibility to distort the amplifier?

Thanks!
N

It depends on the input. If it's a true "pro" line level input (nominal +4dBm), wide-open (or nearly so) is fine. If it is a "consumer" line level (-10dBV) then a bit of attenuation may prevent some overload-related distortion. If the input is a mic level (-40 to -50dBV) then major attenuation is required. Better would be to run the iPod output through a "DI" box, or impedance matching transformer, either passive (no phantom power required) or active (requires phantom power). In any event, if you can get to the mixer, set the channel gain as you would with any input signal: i.e., set the input pad (or "gain" control) and/or the output level on the iPod to a level that doesn't clip (or distort) the input stage.

If the impedance mismatch is such that it distorts wherever you set the output, run through a DI. Whirlwind's "IMP" devices (Whirlwind IMP 2 | Sweetwater.com) are about $50 at Sam Ash/Guitar Center/Sweetwater. The Radial ProDI passives (industry standard in live PA work) are $99 or so. The Radial JPC is a phantom powered stereo device designed specifically for iPod and computer outputs for $199 (Radial JPC | Sweetwater.com).

And... watch the overall level. Most "in-ceiling" systems are meant for voice reproduction, not music, and especially not loud music. Back it down if it starts to distort, and be sure the impedance is matched if you can.

[Mike@DaleN.Y.C.]

I usually find that 3/4 up is usually safe, without too much distortion...remember that the 1/8'' is a headphone level, if you want to go -10 Line (at least I think so, I can't confirm that though) you'll have to get a dock of some sort and use the the bottom connector

[TranscendingM]

Yeah, same here with the about half way or 3/4 of the way up. Personal devices are basically like small amps with not much headroom or cushion. If you push them, they start to distort and break up. Set the iPod around that mark and then do most of the gain at the destination.

[Howie J]

Get one of these if you do this often. It will save you from many a hassle:

Radial ProAV1 | Sweetwater.com

Have two of them at work for teachers to plug their laptops/iPods/etc. to my board for presentations.

Howie J

[NorseHorse]

I've plugged iPods and computers into various boards and amps on MANY occassions. Clipping is never a problem because they can't send a strong enough signal to clip any reasonable line input.

Run it at 100% if you want. Especially if you are running it into a cheap mixer / amp. Sending a stronger signal will reduce the amount of hiss added by the receiving end since you don't need to add gain a second time. The downside to running at full is that you'll run out of batteries slightly faster.

I've used some of the DIs already mentioned, but mainly for the convenience of converting mini to XLR for long runs, either alone or in a snake. (Who wants to keep 100' of 1/8" cable around?!)

[TranscendingM]

Originally Posted by NorseHorse

I've plugged iPods and computers into various boards and amps on MANY occassions. Clipping is never a problem because they can't send a strong enough signal to clip any reasonable line input.

Run it at 100% if you want. Especially if you are running it into a cheap mixer / amp. Sending a stronger signal will reduce the amount of hiss added by the receiving end since you don't need to add gain a second time. The downside to running at full is that you'll run out of batteries slightly faster.

I've used some of the DIs already mentioned, but mainly for the convenience of converting mini to XLR for long runs, either alone or in a snake. (Who wants to keep 100' of 1/8" cable around?!)

I don't think it's a matter of clipping the line input on the destination. the problem is with the unit itself. I don't have the absolute latest and greatest, but the personal players I do have,ipods, cd players, etc., all have this characteristic of sounding distorted when you turn them up full. (Try it for yourself, like in your car for example) It seems around 1/2 or 3/4 mark sounds best.

That Radial box is pretty sweet btw, very handy.