Laptop to Driverack PA2 setup help (levels)

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Grant Bunter
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Re: Laptop to Driverack PA2 setup help (levels)

#16 Post by Grant Bunter »

G'day Howie,

I understand your pain. The answer already has been given, in a round about way, regardless of if your a garage system guy or a pro sound guy.

Your issue is gain. Not the capability of the gain of the entire system. Just the lack of gain available from the laptop.
The driverack expects, no, requires, a line level input at a minimum, and the laptop can't provide that.
So lets look at all the answers to see if any provide you a solution.

Bruce is totally right in saying increasing the gain via the Radial device is a solution. Or plugging into a mixer instead (edit: which you'll probably need for the wedding(s) anyway).
He is also right in saying that trying to fix the problem via adjusting gain in the driverack simply introduces noise when it starving for signal
(Seth, I'd just like to remind you altering gain on the output side of the driverack not only increases noise in this particular case, but also always alters phase and EQ because it's post crossover. Also, the noise thing isn't always about audible, increasing the noise floor in gain makes for a less clean signal that becomes cumulative).

For your purposes, Joe actually gave you the right answer given your personal circumstances.
A quality external USB Sound card with line outputs would change things a lot.
Off the shelf laptops, unless they are squillion dollar jobs, do sound badly. Like every venue owner, every laptop maker by and large knows jack squat about sound. After all, you only need something that can go "ping" right?

You have to remember that the output socket on a laptop isn't a line out, it's a headphone jack. Headphones need different requirements to line devices.

Even though I use a mixer for my laptop and can adjust gain, I still bought a USB Sound Blaster external sound card to use for laptop based music, because the one I bought offers line L + R outs via RCA, and, funnily enough, is an improvement in sound quality. Like from "great" to "killer".
That's on an old Toshiba laptop running win 10 and using an old version of itunes...
Last edited by Grant Bunter on Wed Jun 08, 2022 4:49 pm, edited 2 times in total.
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Bruce Weldy
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Re: Laptop to Driverack PA2 setup help (levels)

#17 Post by Bruce Weldy »

howiez wrote: Wed Jun 08, 2022 3:49 pm OOF, I have a lot to answer.
Setup-wise I have a 3.5mm to dual XLR https://www.amazon.com/dp/B08859NMSZ?ps ... ct_details



into my big knob. https://www.amazon.com/dp/B08B62ZPYH?ps ... ct_details

Then dual XLR out to Driverack. I have the driverack set to -10db (with +4 i barely blink the blinkys).
Excellent! I'd forgotten that the DR had the sensitivity switch in the back.....Haven't looked at the back in a while...all of mine are racked up to keep prying fingers out.

I'll try 60Hz since wave from my PC next chance I get and report back my volts.

Yes, garage most of time, and actually that will run off a receiver and dual BASH sub amps. I wouldn't dare leave my Driverack and Crowns in there while i'm cutting BB for more cabs! When I use it for 2 weddings this summer, it'll be music only and VERY casual, i.e. anyone might play a song, which is why i shot for the big dumb knob. One venue it will be upstairs with a predetermined playlist, any my brother will monitor, during my sons wedding. The other wedding is at a cabin of a friend, and there it will be subject to drinking fingers. So i'll hide the rack best i can, and leave access to the laptop and big knob, or whatever i end up with after all this awesome advice.

That being said, I've been offered a Berry UB1204FX-PRO for free. I may try it, but I'm told there are issues. I like the Yamaha link, thanks Bruce! I was searching Guitar Center, and didn't come across any that simple. Amazon has crazy Chinese ones I'm afraid to spend 49.99 on. There is a company that makes Yamaha knock-offs that look exactly the same. Problem is that they use inferior components. If you go with a mixer (which if you are doing a wedding, it'd make it easier for announcements, etc, then spring for the Yamaha.

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Seth
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Re: Laptop to Driverack PA2 setup help (levels)

#18 Post by Seth »

The biggest reason the voltage measured lower than anticipated is that DMM's can only measure sine waves. It's not a gain issue that can't be appropriately adjusted for in the Driverack. 100%

Yeah, if you're going to want to use a microphone, may as well get a little mixer with a mic input.
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jimbo7
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Re: Laptop to Driverack PA2 setup help (levels)

#19 Post by jimbo7 »

Where's Bill at?

If I may throw my hat in the ring on this subject, I think you just need to get a mixer (a balanced one would be even better)

Like J_Dunavin, I also use MIXXX on a laptop. Before I went all balanced in's/out's my signal went from the laptop to a Behringer U-Control UCA222. From there it went to an old dj mixer with balanced outs -> Driverack -> amps. It worked great and had little to no perceivable line noise. After properly setting the Driverack up; even if I turned the gain to 10 and slammed the sliders up, it never clipped or distorted. I now go straight from laptop to mixer with USB then balanced XLR to Driverack then amp. It's been a minute, but I think I have a healthy balance between laptop volume and mixer volume/gain. The Driverack is pretty much flat.
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Strange Kevin
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Re: Laptop to Driverack PA2 setup help (levels)

#20 Post by Strange Kevin »

And, for more to think about, :)

Keep an eye our for a used "Native instruments Kontrol Audio 6"
Audio interface. Personal vote for the original version, but the Mk2 is similar.

Major selling points are, usb audio, balanced outputs (TRS), and a big gorilla volume knob on top!
Cheers!
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howiez
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Re: Laptop to Driverack PA2 setup help (levels)

#21 Post by howiez »

Grant Bunter wrote: Wed Jun 08, 2022 4:01 pm Even though I use a mixer for my laptop and can adjust gain, I still bought a USB Sound Blaster external sound card to use for laptop based music, because the one I bought offers line L + R outs via RCA, and, funnily enough, is an improvement in sound quality. Like from "great" to "killer".
That's on an old Toshiba laptop running win 10 and using an old version of itunes...
This is probably what I need short term, Thanks! I have a SB pro from 20 years ago for desktop PC with a breakout box and XLR, boy if only they made that for a laptop!
Seth wrote: Wed Jun 08, 2022 5:23 pm The biggest reason the voltage measured lower than anticipated is that DMM's can only measure sine waves. It's not a gain issue that can't be appropriately adjusted for in the Driverack. 100%

Yeah, if you're going to want to use a microphone, may as well get a little mixer with a mic input.
Seth, what kind of signal am I using to set voltage on the tops then? 60Hz for subs and...? I had never thought of the DMM not catching pink noise. I even got a TrueRMS meter last winter since my RatShack was 20 years old!
jimbo7 wrote: Wed Jun 08, 2022 5:38 pm Where's Bill at?

If I may throw my hat in the ring on this subject, I think you just need to get a mixer (a balanced one would be even better)

Like J_Dunavin, I also use MIXXX on a laptop. Before I went all balanced in's/out's my signal went from the laptop to a Behringer U-Control UCA222. From there it went to an old dj mixer with balanced outs -> Driverack -> amps. It worked great and had little to no perceivable line noise. After properly setting the Driverack up; even if I turned the gain to 10 and slammed the sliders up, it never clipped or distorted. I now go straight from laptop to mixer with USB then balanced XLR to Driverack then amp. It's been a minute, but I think I have a healthy balance between laptop volume and mixer volume/gain. The Driverack is pretty much flat.
Jimbo, what kind of mixer are you using since you are straight USB from laptop then balanced XLR to Driverack?
Strange Kevin wrote: Thu Jun 09, 2022 2:01 am And, for more to think about, :)

Keep an eye our for a used "Native instruments Kontrol Audio 6"
Audio interface. Personal vote for the original version, but the Mk2 is similar.

Major selling points are, usb audio, balanced outputs (TRS), and a big gorilla volume knob on top!
Cheers!
I love the simplicity of this Kevin, I see a few on FB marketplace for ~95 (an achievable goal), new for 200 (out of my budget for now).

I love this forum, I can't thank you all enough, world wide help at my fingertips!

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Re: Laptop to Driverack PA2 setup help (levels)

#22 Post by Bruce Weldy »

howiez wrote: Thu Jun 09, 2022 11:44 am
Seth, what kind of signal am I using to set voltage on the tops then? 60Hz for subs and...? I had never thought of the DMM not catching pink noise.
The 60hz tone is between the crossover points of the sub....pink noise is everything. If you feel the need to limit the voltage to the tops, then use something above the high pass of the tops. 500hz...1khz....

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Seth
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Re: Laptop to Driverack PA2 setup help (levels)

#23 Post by Seth »

howiez wrote: Thu Jun 09, 2022 11:44 am
Seth, what kind of signal am I using to set voltage on the tops then? 60Hz for subs and...? I had never thought of the DMM not catching pink noise. I even got a TrueRMS meter last winter since my RatShack was 20 years old!
I think even a trueRMS meter will just give you RMS voltage of mixed signals, instead of peak voltage that we need to set the limiter. But, I'm not 100% positive on that point. I've never used a trueRMS meter, so can't really say for sure.

I set the sub channel's limiter with a sine wave, apply the high pass, apply the low pass (I like to use Linkwitz-Riley here), hook the cab's up, and (using pink noise) EQ the sub to my desired response curve. Pink noise is used for EQing only. Then, with the sub turned off, I set up the tops. Apply the high pass (LR) and EQ it to it's portion of my target curve. Tops don't require a limiter, but I like to put one on just for the sake of why not add a little protection for inadvertent pops and clicks. I use 600Hz sine wave and set the tops limiter at the voltage value that corresponds with the drivers RMS rating. But, others set it for voltage of half the RMS rating and I think that's what Bill has mentioned in the past. To find voltage from Watts; SqRt of (Watts x Ohms) = Volts.

Once those are set, I play a sine wave at the crossover frequency on the sub only and measure the dB level. Turn off the subs, play the sine wave through the tops and adjust the gain for the tops in DSP (not on the amps, keep those full up) until it matches the level of the subs. (Grant, I'd just like to remind you that adjusting the gain at this point, on the output side of the driverack, will not increase noise, and wont alter phase or EQ, even though it's post crossover. If you wanna discuss it further, I'm happy to do so. Open a thread, post in the chat thread, or PM is fine) Then play the sine wave through both, sub and tops together. The dB level should now be about 6dB more than each on their own. If you used Linkwitz-Riley filters at your crossover point, the transition should be seemless. LR filters are -6dB at their specified crossover point and therefore sum to 0dB. If you play them both together and it's actually lower, flip the polarity of the subs (or the tops, either is fine) and it should fix the issue.


Then I finish up with a complete system EQ using pink noise then tweak to taste with familiar music.
Last edited by Seth on Thu Jun 09, 2022 2:28 pm, edited 1 time in total.
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howiez
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Re: Laptop to Driverack PA2 setup help (levels)

#24 Post by howiez »

I was wanting to limit my tops since I'm using the 'trailer park driver'. They are 150w/300w and I have 300w capability, I don't want to smoke them on the first try! My plan was to limit them at 34v, based on that formula, but perhaps 24v is the safer point. Subs will be limited at 49v based on our earlier discussion.

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Seth
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Re: Laptop to Driverack PA2 setup help (levels)

#25 Post by Seth »

howiez wrote: Thu Jun 09, 2022 2:28 pm I was wanting to limit my tops since I'm using the 'trailer park driver'. They are 150w/300w and I have 300w capability, I don't want to smoke them on the first try! My plan was to limit them at 34v, based on that formula, but perhaps 24v is the safer point. Subs will be limited at 49v based on our earlier discussion.
Honestly, either value will be fine. Wouldn't hurt to start conservative.
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howiez
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Re: Laptop to Driverack PA2 setup help (levels)

#26 Post by howiez »

Small update, turns out my youngest son has a Focusrite Scarlet Solo he was using for online gaming/chat whatnot. Link
We're going to try that tonight, see what kind of voltage we can get through the system.
I should have an update shortly

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Re: Laptop to Driverack PA2 setup help (levels)

#27 Post by Bruce Weldy »

howiez wrote: Thu Jun 09, 2022 3:12 pm Small update, turns out my youngest son has a Focusrite Scarlet Solo he was using for online gaming/chat whatnot. Link
We're going to try that tonight, see what kind of voltage we can get through the system.
I should have an update shortly
When putting tones through the driverack - make sure the AFS (Auto Feedback Suppression) is turned OFF.

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howiez
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Re: Laptop to Driverack PA2 setup help (levels)

#28 Post by howiez »

Ok, we have voltage now. I'm getting intermittent readings of over 70v with a 60Hz sine wave.
I have the amp gain set to 11.
I have all EQ and AFS turned off. I have level of tops and subs set to 0.0dB in the crossover.
I'm getting yellow clip lights on the sub/low channels on the Driverack.
The focusrite Scarlet set my windows volume to 100%. I'm using it's volume to control the level into the Driverack.
But at like 1/3 volume i'm getting clipping, before i even get to -20 on the Driveracks display, that doesn't seem right.
Is it possible my test tone is crapola?
I dragged the limiter threshold down until I hold near 48v, when I try 49, it jumps occasionally to 50/51?

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Re: Laptop to Driverack PA2 setup help (levels)

#29 Post by howiez »

I think I have my problem, file i downloaded was 0dBfs, I think i need -10dBfs to be 0dB?
So the file itself is set to clip levels?
Or am I misunderstanding?

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Re: Laptop to Driverack PA2 setup help (levels)

#30 Post by howiez »

Ok, maybe i'm not clipping, I thought the orange light for each channel was clip, but it's green, then orange for Threshold. I guess that means my overeasy limiter is working.
I also just realized, now that I have a pre-amp/line out, I never turned the DBX back to 1.4v, which would explain how I get high levels so quick. I'll change it and try again.
But I'm still curious about what level of test tone I'm putting through, maybe my 0dBfs was fine, I'm just coming out of the USB box too hot now.
That can't be the case though, since it's RCA L/R, that would be consumer level or -10dB correct?
DBX levels at wide open throttle
DBX levels at wide open throttle
Crown XLS 1502 voltage with limiter on
Crown XLS 1502 voltage with limiter on

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