volume attenuator? -10dbV consumer level signal to a +4dbu input ASP8's

G

Goldenvoice388

New member
Hey all, I brought home a sweet pair of Event ASP8's.

I'm still running my trusty fresh-out-of-the-shop 388, and mixing to a Harman-Kardon CDR-20, consumer grade burner (24/96). The problem is, the CDR-20 is -10dbV consumer level outputs. I have it fed directly to the ASP8's. I have the monitor input trim all the way down, and they still crank out over 80db. (no sh*t, huh..)

So, is there any simple, effective, and affordable device which will lower the signal before it hits the Monitors???? (and keep the sound true)?

I know the 388 has balanced outs, which would be soooo simple to run to the monitors, but... I like to add a touch (or more) of compression before hitting the converters in the burner, and I wouldn't get to here that through the Montiors.

Also the fact that to get to know the monitors, I need to spend some time listening to major release stuff...

Lost, Goldenvoice :(
 
something isn't right. -10 should be lower than +4 to begin with. running directly from the +4 outputs should make it even Louder!
 
Could my problem also be related to the fact I'm plugging a 1/4" TS un-balanced into a 1/4" TRS balanced input, even though Event says that should be fine?
 
to the first question: no. -10 is .316 V and +4 is 1.23 V
to the 2nd question: maybe but in my guess probably not the problem. I run balanced +4 and unbalanced -10 signals to the same powered monitors with no problems. I think either you are too close to the monitors or what you think is the lowest volume setting is actually the highest. my monitors if you take them to full attentuation are off.
 
Goldenvoice388 said:
So, is there any simple, effective, and affordable device which will lower the signal before it hits the Monitors???? (and keep the sound true)?
Click to expand...

Yes, if necessary, a fixed or variable pad could give you some attenuation. A fixed pad takes three resistors per channel, plus in and out jacks in a box or on a patchbay or whatever. You tell me the impedance you want and dB of gain reduction and I can give you the resistor values, or I can give you the formula.

A variable pad could just be a stereo 10 Kohm potentiometer, again in a box with input and output jacks, though a cheap one may not be as accurate between channels as you might like. With a pot, connect the line output across the two ends of the pot and take the monitor input signal off the wiper.

I happen to use a Shallco stepped attenuator with 1 dB steps and calibrate 0 dB (all the way on) to the RP200 monitor standard (a -20 dBFS pink noise file produces 83 dB SPL at the mix location with one channel driven. The Shallco pot will run you about $140.

Cheers,

Otto
 
I was looking at the owner's manual for the 388 and on page 24, there's a picture of the rear jack panel; and there is -10db set of Monitor out jacks to feed your powered speakers and there is also a -10db set of stereo outs to feed the HK CD recorder directly without the need to connect it through the speaker's feed.

). The problem is, the CDR-20 is -10dbV consumer level outputs. I have it fed directly to the ASP8's.
Click to expand...
Your hook up ain't right!

Use the independent feeds that the 388 provides you with.

Cheers! :)
 
Goldenvoice388 said:
I like to add a touch (or more) of compression before hitting the converters in the burner, and I wouldn't get to here that through the Montiors.
Click to expand...
The 388 doesn't offer an insert point to the stereo buss where ideally a compressor could be hooked up to feed the recorder and still be able to hear what the comp is doing so, you have to run one in line to the HK's input but to hear the effect of the comp's settings, just get a simple input expander box to feed your speaker's input with a straight feed from the 388 being input 1 and the CD recorder's output being input 2 and control your monitoring volume directly from the speaker's level controls, assuming they have controls.
I have the monitor input trim all the way down, and they still crank out over 80db.
Click to expand...
That's weird?! That control should be able to completely attenuate the volume down to nothing? Bad design if that's so. :o

Cheers! :)
 
Here's what your manual says about input sensitivity:

"Input Sensitivity This control is used to compensate for different signal
levels that appear at the input. The control has a 20dB range; when set at maximum
(MAX), 1.1V RMS input at the balanced ins will produce full amplifier output.
Note that when the signal appearing at the input is too hot, the amplifiers may
overload, causing distortion. If this occurs, attenuate (decrease) the Input
Sensitivity by turning the control counter-clockwise."

So, once you've established that full CCR doesn't attenuate enough, you will need to attenuate the signal in some way. Let me know if that is still the case. I can't imagine another 20 dB wouldn't do the job, so a fixed 20dB pad should get the job done, or you could use a stereo pot. I'm not sure what the specs are on the linked Shallco pot. They do custom pots where you tell them what steps you want and Paul the engineer calculates all the components and they make it. The stepped attenuator is only needed if you are going to use a calibrated monitoring system which I highly recommend.

Cheers,

Otto
 
Oh, thanks so much for all of your help!

Yes, the 388 even has the balanced outputs, which I could hook directly to the monitors, but not being able to hear the compression or any digital clipping would not be a comfortable situation.

The HK's Analog Audio Output is rated at 2V RMS, +- 2 dB.

The stepped pot sounds like a very workable senario. My mind has also been toying with the following, and your input is greatly valued.

Picking up a used P4 or so, decent sound card, and software, from which I could master. Have also been considering going ahead an getting something like a firepod 8 channel, so I could dump all 8 388 tracks, then add synth, etc. Then mix, bla bla bla.

I have a fear here, though, about loosing some of the goodness the 388 contains, but probably not a big worry so long as I stay away from the cheapest converters...?

Thoughts?

I do have a jingle project nearing studio time, and for that will possably have to punt!

I do have a Mackie 1604 sitting in the top rack... could I run the HK outputs into that, and use it to attenuate the signal????

G :)
 
Goldenvoice388 said:
I do have a Mackie 1604 sitting in the top rack... could I run the HK outputs into that, and use it to attenuate the signal????
Click to expand...

Yeah, that will work fine. I"m not sure about the later ones, but the original 1604 had balanced main outs with a polarity reversal w.r.t. the input polarity. If you care, you might want to patch out of the unbalanced buss send, which I'm pretty sure is non-inverting. Also, using one of the stereo aux/returns will make setting the stereo gain easier, as long as the pot is accurate enough.

I happen to be using a stereo graphic eq unit for a purpose kinda like this: just running a signal through it to adjust the gain, but with the eq part switched out. If you have a stereo unit such as that, with a level adjust, it should also do the trick in setting the gain into your monitor inputs as long as you have enough range of adjustment.

Cheers,

Otto
 
Mackie CR 1604. I've had it since the early 90's maybe?

The original 1604 had balanced main outs with a polarity reversal w.r.t. the input polarity.
Click to expand...

So, you're telling me the main balanced outs are in phase reverse by nature?
What do you mean by w.r.t.?

I have the 1604 handy for more elaborate effects routing if needed, but seldom use it as such. It may also be put back into service for live work, as my current mixer has just failed me.

In your thinking on using the 1604, I'm a little lost as to which ins/outs you are recomending. Aux out (ie:basic effects routing) - but in where?
Would this leave the 'main' workings of the board for effects durring mix-down? (I don't "mix" on the mackie, but have run the 388 buss to/through it)...

I do have an old Soundtech stereo graphic, which could be used as you described. (I have 8 channels full parametric if needed) Would probably be my easiest fix. Why didn't I think of that?

Thanks so much Otto!

Goldenvoice :)
 
Goldenvoice388 said:
Mackie CR 1604. I've had it since the early 90's maybe?

So, you're telling me the main balanced outs are in phase reverse by nature?
What do you mean by w.r.t.?

I do have an old Soundtech stereo graphic, which could be used as you described. (I have 8 channels full parametric if needed) Would probably be my easiest fix. Why didn't I think of that?

Thanks so much Otto!

Goldenvoice :)
Click to expand...

That's the one (CR 1604) and yes, they did the inverted out on purpose. Probably figured folks would use the tip output (unbalanced) most of the time and didn't want another inverting stage in the way, maybe? I dunno.

Sorry, "w.r.t." is shorthand for "with respect to". An old habit from physics homework.

The graphic is worth a try, especially if you can bypass the actual EQ part of the thing.

And, you're most welcome.

Cheers,

Otto
 
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