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**jeff_free69** · 11-24-2014, 08:51 PM

Re: ViPeR: Mini-Array ( w/ "buyout" ribbon)

Dressed to Kill!

To clean up the woofer cabinet I used the PE carbon fiber vinyl laminate all around (it got pretty scuffed up on its way from Roman's shop to my basement)

Since the cabinet (originally built by Roman) had dual woofers, I had to improvise a coverup. I'm sure a better craftsman would come up with a more subtle solution; but I opted for the "I meant to do that" approach

To make it a little more interesting I attempted a book-matched pattern on the extra front panel, forming a "V" ( for "Viper" , of course)

I thought I'd eventually replace the screws with something sexier, but ultimately I realized I like the tougher, rock-n-roll looking effect of the stainless steel. It matches the studio decor nicely.

In between the top and bottom is a 12" stand, made from black granite tiles over MDF.

FYI : NYDIY EVENT COVERAGE starts here: http://techtalk.parts-express.com/sh...84#post2022884

Attached Files

**jeff_free69** · 11-24-2014, 09:50 PM

Re: ViPeR: Mini-Array ( w/ "buyout" ribbon)

OK Fast Forward -since then :

I took some time recuperating from lugging all that stuff back and forth! Since this is a bi-amped system I also had to bring all my own electronics. (thank goodness my very understanding girlfriend has an SUV)

The main cabinets are powered by a reasonably hefty emotiva amp. But one thing I haven't paid much attention to is the sub/bottom amplification. All this time I've been using a 25 year old analog electronic PA crossover (EV tapco) and a 50 WPC emotiva mini-amp. And that's what i went to the show with.

Now that the show is over I've moved on to improving that. Funny thing is, its not that easy!

I thought a pair of dayton SA230 sub amps (conveniently on sale), would easily improve things.

Home

http://www.parts-express.com/dayton-audio-sa230-230w-subwoofer-amplifier--300-813

Dayton Audio SA230 230W Subwoofer AmplifierDayton Audio's SA230 subwoofer amplifier delivers all of the clean, solid power required to drive small-to-medium sized subwoofer speaker systems. Its tabletop design is compatible with many other popular electronic devices and different styles of multimedia furniture. The SA230 is engineered to provide high fidelity subwoofer amplification and is tailored for home audio and home theater audio systems. Its variable gain, bass boost, crossover frequency, and phase adjustment guarantee perfect integration with any audio system in any listening environment. Short circuit and thermal protection built-in.Specifications: • Rated power output (1% THD): 156 watts into 8 ohms, 233 watts into 4 ohms • Signal to noise ratio: 85 dB A-weighted • Input impedance: 12K ohms • Input sensitivity: 75 mV • Gain: 0 dB to +10 dB • Bass boost: 25 Hz to 50 Hz • Low pass adjustment: 40 Hz to 180 Hz @ 18 dB/octave • Phase adjustment: 0° to 180° • Dimensions: 17-1/4" W x 3-3/4" H x 13-7/8" D • Power requirements: 120/230 VAC, 50/60 Hz • Stand-by power rating: 120V 0.82W • Weight: 21.05 lbs.With a Dayton Audio 5 year warranty, it’s more than a guarantee, it’s a promise. We stand behind our products and our warranty is a demonstration of our commitment to quality and reliability.

The Vifas start naturally rolling off just above 200 (there is no HPF), plus there's a tough room node null at around 190. So I need to crossover the subs relatively high, ~200. (I need 2 for stereo, because at this frequency they are very clearly directional).

But the SA230 just isn't letting me fill it in as good as my good ol' EV tapco does. Unfortunately the LPF 180Hz upper limit left a bit of a hole. You can see the measured difference in the 2 graphs.

If anything its worse - instead of a ~10 db swing , its now more like 15. Granted,we're only talking about an affected span of 3 or 4 notes, but no sense in marching in reverse!

(Once again - all measurements are at the listening position ~82 inches)

Attached Files

**jeff_free69** · 11-24-2014, 10:02 PM

Re: ViPeR: Mini-Array ( w/ "buyout" ribbon)

Plan C on the sub amplification:

Try an available SPA500 (I have one several years old).

Home

http://www.parts-express.com/dayton-audio-spa500-500w-subwoofer-plate-amplifier--300-807

Dayton Audio SPA500 500W Subwoofer Plate AmplifierOne of the most technologically advanced subwoofer amplifiers on the market today! The Dayton Audio SPA500 subwoofer amplifier is based on a state-of-the-art Class-G circuit topology that combines the proven high power, high fidelity characteristics of a Class-AB amplifier with a patented tracking down converter power supply to achieve an operating efficiency up to 86%. You get the efficiency of a Class-D amplifier without compromising audio quality and reliability. The Class-AB output stage provides the clean and low-distortion sound that audiophiles demand, without any of the instability problems that plague other high-efficiency amplifier designs.This American-designed and engineered amplifier uses patented circuitry that continuously tracks the input signal to modulate or control the voltage available to the output stage. This "tracking" capability delivers the exact amount of power based on demand instead of constantly keeping it in reserve, so the output stage only draws the amount of power that is required at any given time. Less energy is wasted as heat, and more power is available for the subwoofer driver. With its enhanced thermal management, the SPA500 is an upgrade over previous models—making it a nearly bulletproof amplifier choice for today's demanding HT audio and music playback applications.Specifications: • Rated power output: 273 watts into 8 ohms, 540 watts into 4 ohms with 0.92% THD (based on one-third power duty cycle) • S/N ratio: 98 dB (A-weighted) • Low-pass crossover: 30 - 200 Hz, 24 dB/octave • Input voltage: User switchable 115/230V (Euro cord available) • Dimensions: 11-15/16" W x 11-15/16" H x 5-1/4" D; Cutout dimensions: 10" W x 10" H.With a Dayton Audio 5 year warranty, it’s more than a guarantee, it’s a promise. We stand behind our products and our warranty is a demonstration of our commitment to quality and reliability.

Its got a more flexible crossover (200HZ @24db) and a parametric EQ, not to mention more power (though I don't think that's an issue)

Looks like this puts me in pretty good shape - since I already have one, I will only have to buy one (also on sale, plus an additional Black Friday $25 off , so it would actually be cheaper....

Attached Files

**Navy Guy** · 11-25-2014, 01:34 AM

ViPeR: Mini-Array ( w/ "buyout" ribbon)

Looks good, Jeff. Wish I could've got a prime seat to hear these at NY DIY. I was way in the back and off to the side a bit so I'm sure my experience was quite different to yours at home.

**jeff_free69** · 12-27-2014, 01:03 PM

Re: ViPeR: Mini-Array ( w/ "buyout" ribbon)

Recently I finalized the bass module.

On the woofers there was temporarily an Emotiva 50W miniamp, being low-passed by an old ElectroVoice PA analog crossover.

Thats been updated with a pair of Dayton SPA500's (bolted back to back).
They're crossed over around 200, so they're not really sub's

The mains run full-range (no HPF), currently powered by an Emotiva amp (on bottom of rack)

**kenny_k** · 12-27-2014, 07:50 PM

Re: ViPeR: Mini-Array ( w/ "buyout" ribbon)

Jeff, you make things so complicated. ;)

**jeff_free69** · 12-31-2014, 01:40 PM

Re: ViPeR: Mini-Array ( w/ "buyout" ribbon)

Originally posted by kenny_k View Post

Jeff, you make things so complicated. ;)

Sure, Anybody can do it the easy way

In all honesty, it was tempting to leave the EV crossover+ miniamp as is (even at 50WPC, it never broke a sweat).
but it just seemed ... wrong.

I like to think its as much about the journey as it is the destination.
But yeah, I am looking forward to doing some actual recording projects now!

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ViPeR: Mini-Array ( w/ "buyout" ribbon)

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