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GeorgeVW

Messing with FRFR Wet/Dry/Wet and CenterPointStereo

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Stopped by to visit Aspen Pittman on Friday to pick up one of his SpaceStation CenterPointStereo cabinets. Interesting concept — think of it as Mid/Side recording flipped around for a playback system. A 3-way front-facing system (coaxial low/mid driver and a super tweeter) reproduces the L+R signal (or what's in common for both left and right channels) and a full-range speaker placed underneath it fires the difference signal (L-R) sideways and 180°out of phase with the summed front facing output. If you've ever heard the Fender Acoustasonic SFX amp, that's Aspen's patented system at work. While it doesn't give you the hard left/hard right you would get from stereo speakers or a LCR (Left/Center/Right) setup, the big advantage of it is that the whole audience (and the band on stage) gets to hear a big stereo image. Huge spacious delays and reverbs and, man, oh, man, you can hear the Leslie swirl, all from a single source-point. With a 300° dispersion, the sound is very even in level almost everywhere. The surprising (and slightly freaky) thing is that the stereo passes through open doors and windows, since the "space" is created by the way your ears decode and combine the two sound waves. I can play something in the studio and, with the door open, someone standing down the hall can hear it with the same sound field I hear. No more having to sit in a small "sweet spot" to hear a large soundfield( which has always been the problem with using stereo in a live situation — most of the audience doesn't get to hear a fairly large part of the performance all that well). 

 

While by itself it's pretty darn cool, I figured that using it as the post-amp effects amp and feeding the signal from just before the post-processing chain to a separate "center" channel, I could get a pretty good approximation of a wet/dry/wet rig in much less space and with only the Helix and two power speaker cabs — in my case, the Spacestation SFX Mk2 (there is a newer version, but Aspen gave me a deal on the previous model) and an EV ZLX12P powered cabinet. 

 

So, inspired by a combination of the supplied Helix templates for FRFR Wet/Dry/Wet signal chain and Parallel Spans, I've started tweaking up some patches to take advantage of the expanded soundfield this system offers. As a quick review of the signal flow, the chain looks something like this: guitar input > mono stompbox-type effects (anything you'd normally stick in front of the amp) > amp+cab (doesn't matter if your using an amp+cab block or separate amp and cab/IR block) > Split (still experimenting with the variations I can get with Y vs A/B splits) with one side of the split going to Send 1 which feeds the EV cabinet and the other going to > stereo post-processing (delays, mods, verbs, whatever) > L/R outs > Space Station. 

 

Slowly coming up with some basic principles for designing patches to take advantage of this. It seems to be good to use 100% mix on the first stereo effect in the chain to maximize the "stereo-ness" of the final sound, since you've already got a speaker covering the mono "dry" part, and you want to maximize the "wet" to the stereo field. Sticking a stereo limiting amp on the tail end (the LA Studio comp in limiter mode) seems to make for a better result, especially if you're doing some crazy stereo filter stuff in the post section. 

 

As I get some full band practices and gigs under my belt with this system, I'll report back and add to this thread. So far, in the studio, it's pretty durn impressive, and I'm looking forward to pushing it forward. It seems to me like there might even be some way for Helix to do some variation of the routing and phase-flipping stuff in firmware so you could feed a summed signal to one speaker and a phase-reversed difference signal to another and get a similar effect. Hmmmmm … that's probably worth some further thought as well. 

 

 

 

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The concept sounds really cool on the surface, I'm interested in hearing how it pans out.  Pun intended.  :lol:

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The concept sounds really cool on the surface, I'm interested in hearing how it pans out.  Pun intended.  :lol:

 

Biggest problem is that it doesn't record well with traditional stereo miking techniques (and I'm not sure how a M/S recording would work, since it is, in fact, a point source). You can get a little idea by checking out the demo videos Aspen has up on YouTube (look for CenterPointStereo or CPS) under phones, but the videos come nowhere near capturing how enveloping the soundfield is live. I'd have to try a binaural recording, since that does a really good job of capturing a space, and listen back under headphones to see if that captures it (now where did I put that dummy head?). 

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Or just record Helix direct, treat the cab as a live thing only.

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Or just record Helix direct, treat the cab as a live thing only.

 

As a primarily improvisational band, we do a lot of live recording, and that starts to become a very complex setup with the routing on the Helix not quite flexible enough (that I've been able to figure), to do wet/dry/wet and regular stereo out at the same time. You'd need to get the signal taken off immediately post amp model to go both separately to a separate send and fold it back into your secondary stereo outs at the same time, while the post amp (stereo wet) signal needs different mix levels for the isolated wet mix and the regular stereo mix. Don't see a way to do that with existing routing options, so it's one or the other, not both. 

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Hi George any update on this? I have had a Helix Floor about 6 weeks and just had a go with my CPS v2 (that I use with Nord keyboard) with Powercab. Going to try W/D/W and some rotary sounds to see if worth taking to gigs. I suspect not, we play fairly standard rock/pop covers so no ambient/worship sounds with big reverbs/delays etc

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I've been using one for about 2 years and I love it!!I am a music minister at a local church (recently featured in mix magazine) where our sanctuary seats 700 people. I can fill that space with my Helix and the Spacestation and everyone hears a 3 dimensional image. I play JYV variax guitars outfitted with Fishman Triple Play MIDI pickups driving VST instruments on my laptop. I feed the synths into the Helix on USB 3&4 where they have their own stereo path (where I can add processing and use snaphots) then combine and output with the guitar signal into the Spacestation. The side firing speaker projects the my stereo guitar FX & the synths in lush stereo, while my guitar signal is primarily in the front firing speakers. Sounds amazing. I highly recommend the Amp!!

 

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