Open Baffles

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Ali Tait
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Open Baffles

Unread post by Ali Tait »

Had the opportunity to visit Vic of Trans-Fi fame last night to have a listen to his interesting speakers, which I'd discovered in having a mooch around the net looking for info on my Banstanis OB's.

First of all, thanks are due to Vic for hosting me and allowing me to listen to his creations.

Short version - Wow. Just wow..

Long version - Vic took me upstairs to his living room, quite a large space, around 30ft. by 15ft. so room for speakers to breathe. We had a chat about the construction of the speakers and the various earlier iterations that are scattered around the room. Some photos below, but basically he uses some miniature scaffolding parts from a company near Huddersfield I think it is - total cost for all the parts and for them to cut the tubing to length was £99 delivered, so a bit of a bargain there. I'll try and find a link. The bass drivers are bolted together facing each other using some spacers of around 4-5", and hang in a cradle of the scaffolding supported by some small loops of cable. This seems to work really well - I checked to see if any vibrations were making there way from the drivers to the scaffolding and couldn't really detect anything, so this arrangement appears to work really well. The PRV mid/top drivers are hung from a U shape bracket, again with a loop of cable under the top drivers' magnet. Vic made some fish plates, more or less the shape of a dog bone to connect the four drivers together, all just hanging there from the top driver. The weight of the drivers keeps them steady. They are connected series/parallel a la Edingdale stylee.

It was all digital files we listened to, one particular track that struck me was a live version of Man/Machine. I can honestly say I've never heard a speaker in a living room get closer to how a live gig sounds ( or at least how I imagine it would sound not having been there). The scale, dynamics and sheer drive to the bass has to be heard to be believed - I've certainly never heard anything like it in a living room, it really is like being at the gig. The funny thing is though, the bass is in no way overblown, nor does it interfere with the mid/tops in any way, it's just there when it needs to be, and boy is it there! As Vic commented, you can't really appreciate music like this until you hear it with the full frequency range reproduced, and having now heard this for myself, I have to agree.

The 4" PRV drivers appear to be quite a bargain- I think they are around £75 each?

Mids and tops were very well reproduced, huge soundstaging too. Very clean and clear, and I didn't miss a tweeter at all.

Further details - The bass drivers are crossed at 275hz to suit the PRV drivers, using the DSP in the Behringer amps. I was surprised to learn there is no DSP used to tweak the low bass response due to the lack of baffle, these drivers are so capable that none is required - I can certainly vouch for that. Only caveat is sensitivity is not great, but as Vic again commented, watts are cheap - he's using a couple of 6000w NX Series Behringers which he paid £300 each- all he does is up the gain by 10db to match levels with the PRV's. Other than that they are run open, as I believe are the PRV's - they are run with a pair of Temple Audio boards, powered with a pair of supercap power supplies.

Well that's about it, I'm sure Vic will correct any inaccuracies, just like to say thanks again, it was a pleasure to meet you.

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EDIT - link to the metal store -https://www.themetalstore.co.uk/

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karatestu
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Re: Open Baffles

Unread post by karatestu »

Thanks for posting that here Ali. Extremely interesting. I have read about his adventures over at Audio talk (i think ??). Just goes to show what can be achieved and no dsp on the bass frequencies is very impressive :clap: It is a shame that my room is not really big enough for OB as i need the speakers to go right back against the wall if possible.

I have tried a very crude attempt at open baffle by just removing the back panel of my bass cabs. I liked some of what it did, i heard bass detail i had not before but with the speaker not far enough from the wall i don't think i was getting the full dipole effect. There was a "wooly" quality to the bass and it did not seem any quieter and there was no lack of it either.

Shame they look so industrial as i am not sure i could tolerate that (or the wife). Maybe i could put some on castors and wheel them out for listening ? Doc liked OB and i think i do to (along with many others).

:guiness;
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Ali Tait
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Re: Open Baffles

Unread post by Ali Tait »

I suppose the bass drivers could be turned sideways, to allow then to be up against a wall. Agree they are not the prettiest, doesn't bother me, but I did think that a frame could be made so they could be covered with cloth to make them a little more domestically acceptable. I would say they are less intrusive than a lot of OB's I've had or seen though.

There's a thread on Lenco Heaven on the history of these-

https://www.lencoheaven.net/forum/index ... ic=31371.0

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Re: Open Baffles

Unread post by savvypaul »

karatestu wrote: Thu Feb 06, 2020 11:51 am Thanks for posting that here Ali. Extremely interesting.
:guiness;
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Re: Open Baffles

Unread post by NSNO2021 »

+2 Wonderful thread 👍
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Ali Tait
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Re: Open Baffles

Unread post by Ali Tait »

Yes, great piece of lateral thinking on Vic's part, and such a great result too.

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Re: Open Baffles

Unread post by karatestu »

I have read on AT that he does in fact use the dsp :cry:
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Re: Open Baffles

Unread post by Latteman »

nilsatisnisioptimum wrote: Thu Feb 06, 2020 4:22 pm +2 Wonderful thread 👍
+3, I like the build concept and with a bit of imagination a cloth covering would be cool too
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Ali Tait
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Re: Open Baffles

Unread post by Ali Tait »

karatestu wrote: Thu Feb 06, 2020 5:53 pm I have read on AT that he does in fact use the dsp :cry:
Waiting for clarity, it is used for the crossover though. Either way I’m not bothered, they sound fantastic.

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