Spatial Black Hole - Active Bass Trap?

poseidonsvoice · « **Reply #40 on:** 20 Feb 2012, 12:30 am »

Quote from: JohnR on 20 Feb 2012, 12:28 am

Clayton, do you have waterfall plots that yiu can share? The steady state plots don't really show that the unit acts as an absorber.

+1.

Anand.

JDUBS · « **Reply #41 on:** 20 Feb 2012, 01:24 am »

Quote from: poseidonsvoice on 20 Feb 2012, 12:30 am

+1.

Anand.

+2!!

-Jim

Habs Fan · « **Reply #42 on:** 20 Feb 2012, 02:42 am »

Wheres the mic?Looking at the pic's on SC's website I don't see the mic element ,it is not mounted in front of the woofers dust cap as in the Phantom.

Spatial Audio · « **Reply #43 on:** 22 Feb 2012, 12:45 am »

Spatial Black Hole - Time Domain Measurements

Here are 2 types of time domain plots: 3D Waterfall and EDT showing reduction in modal ringing:

A home theater subwoofer was used at the front of room, with a single Black Hole located against the middle of the rear wall. This test room is 11.7 W x 26 L x 8 H. These dimensions generate axial modes at these frequencies: 21.7Hz, 43.4Hz, 65Hz, 96Hz etc. These show up as sharp ridges in the Waterfall plots.

Black Hole OFF /\

Black Hole ON /\

Black Hole OFF /\

Black Hole ON /\

The decay time is cut by 40% to 50% below 63Hz mark.

Happy Listening,

Clayton Shaw
Spatial Computer / Clayton Shaw Audio Technologies LLC

JohnR · « **Reply #44 on:** 22 Feb 2012, 08:07 am »

Thank you for those

Rclark · « **Reply #45 on:** 22 Feb 2012, 08:11 am »

John, what do you think of that?

JohnR · « **Reply #46 on:** 22 Feb 2012, 08:43 am »

What do I think? Well, if you look at the waterfall plots at the 43 Hz resonance, it's fairly clear that the "Black Hole" reduces decay time at low frequencies quite dramatically. The reduction in decay time is apparent down to 20 Hz, and it seems to be effective up to maybe 100 Hz, although to a lesser extent. It looks to me that there's a frequency below which active absorption becomes more effective than passive absorption.

poseidonsvoice · « **Reply #47 on:** 22 Feb 2012, 02:03 pm »

Quote from: JohnR on 22 Feb 2012, 08:43 am

What do I think? Well, if you look at the waterfall plots at the 43 Hz resonance, it's fairly clear that the "Black Hole" reduces decay time at low frequencies quite dramatically. The reduction in decay time is apparent down to 20 Hz, and it seems to be effective up to maybe 100 Hz, although to a lesser extent.

I agree with you wholeheartedly here.

Quote

It looks to me that there's a frequency below which active absorption becomes more effective than passive absorption.

Okay, what do you/we mean by that? I think that the 40-50% cut below 63Hz as Clayton shows is great. Passive absorbers would need to be very large in order to replicate this, and probably numerous around the room, compared to the addition of a single equalized sub on the back wall. Smarter minds of the acoustics/room treatment industry can enlighten us more.

Of course the mic was only taken at one position, the listening position, which to most is all that matters. When you are talking about multiple seats, this may or may not change, dunno, until we see measurements.

Overall, very pleased to see this, although I am not completely surprised.

This would be great in smaller rooms, apartment dwellings, etc...saves space!

Anand.

JohnR · « **Reply #48 on:** 22 Feb 2012, 02:08 pm »

I think we're in agreement...

Habs Fan · « **Reply #49 on:** 23 Feb 2012, 05:00 am »

It appears to work as advertised at 60hz and below.I wonder if the rear mid wall positioning was found to give best results in that room or was it just chosen arbitrarlly?

spiritofmusic · « **Reply #50 on:** 24 Feb 2012, 04:33 am »

Hi, just an update as a v.happy user of the Black Hole, after a few weeks of continual listening. Bass resonances have really cleared in my room, esp.noticeable on bass heavy compressed cd's. So much so that I often pop around to the back of my Zu Def2s (4 x 10" rear firing woofers) to check if they're still pumping out bass (which they are, of course). What has happened is that the bass hump anomalies that were previously apparent as a colouration in my room are all but eliminated leaving a v.tight bass response, esp. enhancing kick drum, plucked bass notes etc.
The fantastic consequence of this is that mid range intelligibility, treble extension, and as a consequence transparency and soundstage have all improved dramatically.
I am not normally a fan of room treatments/system tweaks etc, and remain skeptical of so-called 'improvements' like the bsgt qol, neutralaudio x-drei, lessloss blackbody, shakti stones, which in my opinion only offer unscientific faddiness to this hobby. But the Black Hole gets my unambiguous recommendation, esp. since I suspect strongly that smaller/more difficult rooms, with worse bass nodes/standing waves than mine will benefit even more from it's use. The only other system improvement I would positively recommend is ditching all conditioners/filters etc. and going over to balanced power using a minimum 4kV transformer to plug all equipment into, eliminates restriction in dynamics that virtually all other devices other than balanced power impose on system sound.
I'm in contact with Clayton to see if he advises an additional unit in my room, since my space is much larger than the 25' x 15' space he recommends 1 unit to serve

RCduck7 · « **Reply #51 on:** 24 Feb 2012, 11:19 am »

Quote from: spiritofmusic on 24 Feb 2012, 04:33 am

The only other system improvement I would positively recommend is ditching all conditioners/filters etc. and going over to balanced power using a minimum 4kV transformer to plug all equipment into, eliminates restriction in dynamics that virtually all other devices other than balanced power

Slightly of topic but you mean something like these??

Those are twin balanced transformers.
I do have a 500VA for pre and source and a 1000VA for the amp section.
I got these from here...
http://www.sacthailand.com/
Their biggest is a 1500VA but you recommend a 4000VA for all equipment??
But anyhow, for the best results i think it is better to have more then one to not mix amps with sources, pre or other digital equipment in one block.

spiritofmusic · « **Reply #52 on:** 24 Feb 2012, 02:16 pm »

I'm based in the UK, so not familiar with that item, but yes balanced power transformer is the way to go. I would recommend nothing below 4kV, esp. if you're going to plug more than 1 power amp in. You don't even have to spend a ton of cash, my UK based transformer the equivalent of $600, a tenth of what I spent on my audiophile conditioner/filter before, although I am v.interested in a pro version called the Westwick 8kV(!) used in top London recording studios, 85kg of copper in your room! The advantage is that there is virtually absolutely no current limiting to the power amps which even the best conditioners can't compete with, and hence no restriction to dynamics.
So start off cheap, and see where you get.
All I know is this, plus the Black Hole are far and away the best bang for buck upgrades for my room/system, and I couldn't go back.

RCduck7 · « **Reply #53 on:** 24 Feb 2012, 10:15 pm »

Quote from: spiritofmusic on 24 Feb 2012, 02:16 pm

I'm based in the UK

Then you are a neighbour, or sort of. I'm from Belgium.
I'm intrested in the transformers you mention, i'll send you a PM.

Rclark · « **Reply #54 on:** 24 Feb 2012, 11:23 pm »

Wow. And no need to bulk up the room with traps. Very cool.

I'd also heard about transformers but never seen one.

Glenn Kuras · « **Reply #55 on:** 8 Mar 2012, 09:34 pm »

Quote from: JohnR on 22 Feb 2012, 08:43 am

What do I think? Well, if you look at the waterfall plots at the 43 Hz resonance, it's fairly clear that the "Black Hole" reduces decay time at low frequencies quite dramatically. The reduction in decay time is apparent down to 20 Hz, and it seems to be effective up to maybe 100 Hz, although to a lesser extent. It looks to me that there's a frequency below which active absorption becomes more effective than passive absorption.

Well may I disagree??

Actually we looked at something like this and I would say it does have its place but there are ways that passive can work if built right. And you don't need to fill up the room. Honestly I do like the theory behind active though
See below.

http://www.audiocircle.com/index.php?topic=104363.0

Rclark · « **Reply #56 on:** 9 Mar 2012, 12:24 am »

You're disagreeing with his interpretation of the graphs

why?

How many traps do you think it would take to match that performance, and how much would it cost?

JDUBS · « **Reply #57 on:** 9 Mar 2012, 12:54 am »

Quote from: Rclark on 9 Mar 2012, 12:24 am

You're disagreeing with his interpretation of the graphs why?

How many traps do you think it would take to match that performance, and how much would it cost?

Seriously? Uhh...his link should tell you exactly why. He has a competing product - which doesn't belong in this thread.

-Jim

Rclark · « **Reply #58 on:** 9 Mar 2012, 01:04 am »

Link doesn't say why he thinks John is wrong, nor the second question. Just curious.

The link is just a thread to a basstrap.

JohnR · « **Reply #59 on:** 9 Mar 2012, 01:58 am »

He is disagreeing with the supposition "It looks to me that there's a frequency below which active absorption becomes more effective than passive absorption." The new product "Scopus" is a tuned trap, which I wasn't considering. The one tuned at 40 hz is effective on a 34 Hz mode in the third graph posted here:

http://www.gearslutz.com/board/studio-building-acoustics/692050-gik-realtraps-5.html#post7597560

That is with 8 traps at $239 each.

Looking at the tiny absorption graph on the product page, it doesn't look like it will have much effect at 20 Hz. However that can always be proven wrong by building a different product.