Front wall diffusers...

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es347

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Front wall diffusers...
« on: 19 Dec 2010, 04:31 pm »
Hey everyone, this board has been deader than disco recently so here's an opening volley for ya.  Since my VR5 annies have rear-firing tweeters, why would I want to have diffusers on the front wall?  It seems contrary to what Alberts tweeters are meant to achieve.  While on the subject, what about the Shakti Hallograph "optimizer"?  What's the magic of that $1K piece of wood that anyone could make in their wood shop?  Not meant to offend those who own them, but it seems like another Tice clock or Brilliant Pebbles deal.

Merry Christmas guys.

DARTH AUDIO

Re: Front wall diffusers...
« Reply #1 on: 19 Dec 2010, 05:11 pm »
Hey everyone, this board has been deader than disco recently so here's an opening volley for ya.  Since my VR5 annies have rear-firing tweeters, why would I want to have diffusers on the front wall?  It seems contrary to what Alberts tweeters are meant to achieve.  While on the subject, what about the Shakti Hallograph "optimizer"?  What's the magic of that $1K piece of wood that anyone could make in their wood shop?  Not meant to offend those who own them, but it seems like another Tice clock or Brilliant Pebbles deal.

Merry Christmas guys.

I own a pair of the Shakti Hallographs. Don't knock'em before your try them. They're amazing!! I've had non-audio friends over and they couldn't believe what they did to the sound.

bpape

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Re: Front wall diffusers...
« Reply #2 on: 19 Dec 2010, 05:51 pm »
Having rear firing drivers is exactly why you would want diffusion on the front wall.  Instead of getting a direct, beamy bounce from the rear, you'll get a much wider presentation with all of the energy preserved but arriving from different directions and different times to simulate a larger acoustic space up front - at least in the higher frequency range.

Byan

es347

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Re: Front wall diffusers...
« Reply #3 on: 19 Dec 2010, 06:19 pm »
Thanks for the replies.  How would diffusers like the shaktis work in the front corners as opposed to the wall directly behind the speakers?

JackD201

Re: Front wall diffusers...
« Reply #4 on: 20 Dec 2010, 04:56 am »
Spot on Bryan and by the way may Leslie Nielsen live on forever through your avatar :)

The Hallographs make sense especially when placed whee they are recommended, in the corners. Whether one could do better for the same amount is another issue altogether. It would really depend on what the room owner wants to achieve rather than the Hallograph's intrinsic properties or more simply what they alone bring to the table.


es347

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Re: Front wall diffusers...
« Reply #5 on: 20 Dec 2010, 05:34 pm »
I read a review of the hallographs in one of the vaunted rags and they found that they were most effective when placed directly behind the speakers which won't work for me.  The only place I can put them is in the corners.  So Jack, is that the recommended placement?  thx.

satfrat

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Re: Front wall diffusers...
« Reply #6 on: 20 Dec 2010, 07:56 pm »
It's my understanding that a rear firing tweeter's purpose is to add ambiance to the soundstage, more soundstage depth. Anything that would enhance that rear driver's purpose would be a plus I would imagine. Those Shakti Hallograghs are probably the most expensive way to achieve that tho, but they do less obtrusive than wall diffusers IMHO. While I have installed VMPS Ambiance Tweeters on the back of my Odessey Lorelei's and can attest to their effectiveness, I have no room for either diffusion option so I can't offer any actual experiences other than a personal visual preference opinion.  :|
 
Cheers,
Robin
 
Cheers,
Robin

JackD201

Re: Front wall diffusers...
« Reply #7 on: 20 Dec 2010, 09:02 pm »
Hi Gavin,

Yup. They were designed to be placed in the front corners. Practically anything diffusive in corners is a good thing for high frequencies anyway. Even cylindrical bass traps are diffusive at these frequencies. By looking at them, especially their height I can imagine a pretty good ray trace result with them in a room. What I can't seem to wrap my head around is how the resonant chambers work, or for that matter those little resonators by Tsang and Synergystic. I've heard the latter two and in a very quiet room they do make a difference. My only problem was that the differences were firstly faint and secondly were not always positive. Another variable to be bothered with. Who wants to get up and remove them little bowls and put them back on again when the differences are easy to listen past. The Shaktis however, resonant chambers aside, appear to have enough surface area to actually work resonant chamber or not.

Hi Robin,

Albert's ambience tweeters are a bit different. If one were to stand close to ear level with them from directly behind the speaker one would hear spookily full range sound. It's a strange thing for sure. While it does add corner fill, widening and increasing stage height in the rear, bringing up the rear ambience levels actually moves the stage forward and not back. Given standard untreated drywall front walls, most folks that prefer a stage behind the speaker plane keep their ambience tweeter levels low either off or 8'oclock at most, those at the plane somewhere at 9 o'clock and those that relish walk in stages closer to 11 o'clock. This of course depends on the front wall treatment. Where diffusion comes in handy is that when properly done overall tonal balance is kept even avoiding late arrival time beaming from the rear tweeters. An issue for those that want that walk in soundstage but not the HF boost that comes with running the rear tweeters pretty wide open.

It's a very thoughtful and useful feature for adapting the VR family of loudspeakers into varying acoustic spaces, especially non symmetrical ones in both shape and building materials but like any feature requires a bit of experimentation. Thankfully, it comes after the speakers have been set up for desired tonal balance with the tweeters off making the process more of an icing on the cake feature having distance to boundaries, toe-in and rake angles covered.

In the end I guess what it gives the owner are options for choosing one's preferred ratio of direct to reverberant energy. A subjective one of course but the adjustability actually means one may require less acoustical treatments versus say true dipoles. After 6 years and owning and using 5 different models from the 4jr to the 9 SEs, it's a feature I've come to rely on for the sheer utility and ease of use.

:)

Jack