Proper Monitor Levels/Monitor signal chain

[Mitch Connor]

I've always thought my Tannoy Active Reveals (the original blue ones) were ridiculously loud for nearfield monitoring even though 50 watts isn't really on the high side of things. Anyway, in the past when I had them directly connected to the main outs of my Firebox I would barely raise the main output volume knob above the minumum -80 db line. In conjuction I would also drop the main out fader on the Firebox's virtual mixer -6dB. However, after reading this post:

http://www.gearslutz.com/board/1997224-post23.html

it appears that this is not ideal and that I may be running my audio signals through my Firebox's D/A converter at sub-optimal levels (please correct me if I'm wrong already). So, I recently brought out my old analog Mackie 1642 VLZ mixer and have been running the main outs of the Firebox into a stereo line level input on my the Mackie mixer and from there connecting my Reveals to the control room output.

With a -6dBFS 440Hz Sine wave test tone running out of the firebox (or maybe it was -4dbFS) and the virtual mixer fader all the way up at 0dBFS along with the main out volume knob all the way up (which reads 0 on the front of the unit though the manual says it ranges from -80db to +10dB. Maybe there's a difference between a lower case 'b' and an uppercase one. There are so many different dB scales that it gets rather confusing. Everything I've researched always shows 'B' being in caps, so I figure it's probably a typo. Perhaps the +10dB is a typo too) my Mackie's meter reads 0 dBu. Note that this is with all of the analog faders and trim pots at unity.

Everything so far seems good to me, however, I can just barely raise the control room output knob above infinity. At the 9 o'clock level it's already really loud. I know I can easily just bring the main faders down on my analog Mackie mixer to adjust the volume, but thought I was supposed to keep the signal around 0dBu to achieve the best s/n ratio running to my monitors. I wish there was a way to adjust the power amp in the Tannoy Reveals, but there isn't.

So my question is, is this normal? I never thought that reducing the digital level on the Firebox output would reduce the bit rate running to my monitors, but I guess that's the case. Is there something I'm missing? It's not the biggest problem in the world, but it seems strange that an 8 o'clock setting is a comfortable listening/mixing level when it's range is from 7 o'clock to 5 o'clock. It's not like there's a built in power amp in my analog mixer, only the monitors.

I searched the forums, but didn't really find anything directly related to this. Also since this is my first post here on Gearslutz, I apologize if there is a more appropriate forum/subforum that I should have posted this in.


Thanks,
Justin

[Mitch Connor]

It's been a few weeks without a reply so I thought a bump would be acceptable. Still curious if this is typical for active nearfield monitors. It seems like they have way too much power for their intended application. I could easily see myself blowing a speaker cone if I used half of their rated power. Any comments on this somewhat trivial question is greatly appreciated.

[Ethan Winer]

I use a small Mackie mixer the same way as you. I have the power amps set to be comfortably loud when the Mackie's output volume is not quite half way up. If your Tannoys don't have input levels I'd call that a serious shortcoming! Are you at all handy with a soldering iron? Four resistors will do exactly what you want - 10K in series and 1K to ground for each channel. If you can't solder, go to Radio Shack and buy an online passive volume control. The one I've seen for headphones with 1/8 stereo connectors should work.

--Ethan

[Mitch Connor]

Thank you for the reply. I've soldered some guitar pickup wires in the past, but don't think I'll be touching the my monitors. I just figured I must have something wrong in my gain stage (if that's the correct use of the phrase) if I can't run my monitors above a 1/4 of their power (just a rough estimate) without killing my ears and/or destroying the speakers.

The next monitors I buy will likely be passive, or at least have some way to control their internal power amp.

Originally Posted by Ethan Winer

I have the power amps set to be comfortably loud when the Mackie's output volume is not quite half way up.

You're talking about the control room output level, correct? Is everything else at unity with audio signals peaking at 0dBVU?

[steveschizoid]

A-Designs makes a passive attenuator (the ATTY); I have my Adam S3A's hooked up to one; it works great. Also, both your speakers and your convertor can input/output (respectively) -10dBv or +4dBv. Make sure they are both set to +4

[Ethan Winer]

Originally Posted by Mitch Connor

I've soldered some guitar pickup wires in the past, but don't think I'll be touching the my monitors.

No, I just meant wiring up adapter cables between the mixer and speakers, with the resistors inline with the cable.

You're talking about the control room output level, correct? Is everything else at unity with audio signals peaking at 0dBVU?

I use the Line Out on my mixer, but yeah, that's the general idea. The outputs from my sound card go to channel inputs on the mixer, and those stay at Unity most of the time.

--Ethan

[OVERNIGHT]

The Blue Sky monitor website has a system for calibrating monitor chains using a $40 radio shack dB reader and their own sine wave files that you can down load for free off their site. It's for film and tv use respectively but it's within the realm of normalcy when talking bout monitoring music.

I try to keep my software master outs at -0dB and do my reduction after the D/A. There is a bit rate shave-off (so I'm told) that happens as you roll off in the box. If stuff is hitting the output too hot then I have an issue within the session and need to start bringing down faders or inserting a bus comp. If nothing's in the red at the output and you can barely raise the fader then I'd think about some kind of clean/passive attenuator like the ATTY set sufficiently low that you could control a separate fader with reasonable range.

Active monitors with no output gain control seems like a bad design. What's to say they're both outputting at exactly the same level? Two ATTY's mentioned in an earlier post would fix that. Or a new pair of active monitors with gain controls.

[Mitch Connor]

Originally Posted by steveschizoid

A-Designs makes a passive attenuator (the ATTY); I have my Adam S3A's hooked up to one; it works great. Also, both your speakers and your convertor can input/output (respectively) -10dBv or +4dBv. Make sure they are both set to +4

My question here is, what's the difference between using a passive attentuator and just lowering the main out on my analog mixer? I imagine it has something to do with the signal to noise ratio of the mixer, but don't see how it would differ.

Also, the old school Tannoy Active Reveals only have a power switch and combo neutrik inputs on the back (with the 1/4" using unbalanced TS connections). As long as the an XLR cable is used it says they're accepting a balanced signal (+4). And the Mackie mixer only has a -10/+4 switch on the main outs. According to the manual the C/R outputs are balanced so again I'm assuming as long as I use a balanced cables I'm getting a +4 out from the mixer to a +4 in on my monitors. Note that I'm using 1/4" TRS to XLR cables.