scope for PA processing

ernest@303.nu · Post by **ernest@303.nu** » Sun Dec 12, 2004 12:29 pm

Now that we finally have our own PA system (total amplifier power 4.8kW RMS, 7.8kW peak) to throw out our little parties I spent some time using my Scope system (21DSP) to optimize the sound. The results were *extremely* good!

For those who know: our system consists of 4 old-but-trusty w-bin bass boxes (rated 800W each), 2 Cerwin Vega "Earthquake" bass horns (1.2kW each) and 2 Cerwin Vega 3-way tops (full range), also 1.2kW each. The (cheap) amplifiers we use are powerfull, but not known for their punchiness, so I had to compensate for that as well.

I ran everything at 96kHz/1msec latency. Crossover to the different amplifiers was done by Creamware (12dB/oct sounded best), as well as seperate processing for *each* amplifier channel!
This processing (for each amplifier channel) consisted of 31 band graphic EQ, 4 band parametric EQ, 4 band multiband compression/expansion (Optimaster), low/high enhancement (PsyQ), limiter set just below amplifier clipping level(with long release, thus working as a leveler). The channels feeding our bass-amplifier also had a bit of SPL Transient Designer on it to allow for tighter release. This especially worked great on the w-bins, which tend to be a bit 'lazy' and 'slow' at very low frequencies. The Transient designer compensated for this sluggish response, resulting in a tight bass.
The mid/high speakers were delayed a couple of samples to compensate for the longer signal route of the bass speakers caused by it design (time alignment), allowing for even tigher bass perception (no 'lag'). I did this by ear rather than calculating the time difference.

Input from the DJ mixer to Creamware went through an inexpensive Behringer compressor, set as leveler (ratio at "limiter" and with long release) to protect the A/D from over-enthusiastic DJ's. Output to the amplifiers went through CW analogue out (mid/high) and aditional D/A at the ADAT-port (@ 96kHz) for the lows.

The result: extremely warm yet tight sound. Bright but easy highs (you could even talk in front of the speakers), detailed mid, and thundering lows. A bit like hifi, but than at PA-level

A/B-ing the system with/without Creamware processing is a bit like comparing Yoko speakers to the newest active studio monitors.
A/B-ing 48kHz and 96kHz was very audible (better stereo, silk-like highs at 96kHz) so I decided to go for 96kHz.

Of course a 21 DSP system is a luxury to enhance a relatively inexpensive PA system, but I have my Creamware system anyway so why not use it outside the studio!

The 'winners' of this setup were Optimaster and PsyQ (in that they made the greatest difference). But really, all of the effects had their function and I really doubt I will ever dare to process a PA system *without* creamware anymore!

OK just wanted to share my enthousiasm

[edit] by the way the party was steamin' beyond sunrise

[/edit]

<font size=-1>[ This Message was edited by: ernest@303.nu on 2004-12-12 12:40 ]</font>

nprime · Post by **nprime** » Sun Dec 12, 2004 1:33 pm

That's so cool! I've always thought that Scope would be useful as a real time crossover for P.A.'s. Great to hear it worked so well, especially the extra processing you were able to pull off, imagine what it would have cost to do what you did with dedicated hardware...if you even could.

I hope someone at Creamware reads this, it's a completely un-tapped market for them.

R

nitty gritty · Post by **nitty gritty** » Sun Dec 12, 2004 1:50 pm

Feckin ace bro!!!

It's every dj's dream to play on a mega system and for the sound to be incredibly good.

Excellent work for the innovative thought process.

Whereabouts are you based and what do your djs play I'd love to know?

ernest@303.nu · Post by **ernest@303.nu** » Sun Dec 12, 2004 3:00 pm

On 2004-12-12 13:50, nitty gritty wrote:
It's every dj's dream to play on a mega system and for the sound to be incredibly good.

4.8kW RMS isn't exactly mega in my opionion... but for a private system it's quite OK

And yes, the DJ's that played that night really enjoyed the sound. (we've placed them facing the PA so they didn't miss a thing)

Whereabouts are you based and what do your djs play I'd love to know?

Near Nijmegen (the Netherlands). We throw out free parties mainly in squats and we have a semi-permanent setup at a squatted farm where we had parties up to 1500 visitors. Until recently we had to borrow or rent our soundsystems, but the hassle and (often) lack of quality made us buy our own system. Not a single second of regret

The DJ's play all styles of electronic music; techno/tekno, electro, drum'n'bass, IDM, etc.
I tuned the system for all kinds of music and now it pretty much eats everything using the same Creamware project file.

On 2004-12-12 13:33, nprime wrote:
I've always thought that Scope would be useful as a real time crossover for P.A.'s. Great to hear it worked so well, especially the extra processing you were able to pull off, imagine what it would have cost to do what you did with dedicated hardware...if you even could.

There are dedicated PA-processors that do the same thing (cross-over, processing and limiting in one unit), but they're expensive indeed, and not very powerful (easily driven to DSP overload)
Besides that, nothing offers this kind of flexibility; any crazy routing idea can be instantly excecuted. (which I did

)

Post by **garyb** » Sun Dec 12, 2004 3:40 pm

Immanuel · Post by **Immanuel** » Sun Dec 12, 2004 5:33 pm

Great to hear, that it works. I use Scope for x-over too. I would never use it to feed a tweeter/midrange unit without analog lo-cuts as a security, just in case a pop, should arise, or an extremely rare random shutdown ... "puff" from the converters.

ernest@303.nu · Post by **ernest@303.nu** » Sun Dec 12, 2004 6:37 pm

On 2004-12-12 17:33, Immanuel wrote:
I use Scope for x-over too. I would never use it to feed a tweeter/midrange unit without analog lo-cuts as a security, just in case a pop, should arise, or an extremely rare random shutdown ...

I thought about that.... but we use very powerful full-range cabinets for the mids and highs (each channel has 2x12" low/mid, 2" mid, bullit high, and internal passive x-over) so the tops should be able to cope with anything they could possibly be fed by the D/A. (security is within the passive filtering)

Cool to hear someone else is also using CW on their PA system!

Post by **hubird** » Sun Dec 12, 2004 10:16 pm

great job Ernest!
I used to use Cerwin Vega in a band in the past, it's great stuff, specially in the lows.

Damn, I missed this party, please put me on a email list somehow, I wanne join them all !!
I'll never forget the last summer party, it was great

ernest@303.nu · Post by **ernest@303.nu** » Mon Dec 13, 2004 3:50 am

On 2004-12-12 22:16, hubird wrote:
Damn, I missed this party, please put me on a email list somehow, I wanne join them all !!

We don't have a mailinglist yet. Next party will be december 26th! (5 year anniversary)

I'll never forget the last summer party, it was great

Yeah it was pretty sweet!
Good news for you: we won't stop organizing parties

Immanuel · Post by **Immanuel** » Mon Dec 13, 2004 4:01 am

I don't use it for PA. I use it for monitoring.

ernest@303.nu · Post by **ernest@303.nu** » Mon Dec 13, 2004 10:54 am

On 2004-12-13 04:01, Immanuel wrote:
I don't use it for PA. I use it for monitoring.

In what way do you use x-over when monitoring? (just curious)

Immanuel · Post by **Immanuel** » Mon Dec 13, 2004 11:01 am

Well, my monitor system is kind of ... disintegrated. For 2000Hz and up I use JBL 4411. Below that I use Epos es11, which are very "hi-fi". The foam surrounding on the jbl basses are gone ... age killed them.

So I use 48dB filters in series for a 96dB/oct x-over. This gives perfectly flat response, when summing the signal. I haven't checked for phase-issues though.