Graham Holliman Velocity Coupled Infra Bass Speaker? - Page 4 - diyAudio
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Old 15th June 2004, 09:15 AM   #31
7V is offline 7V  United Kingdom
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Sorry guys but I still don't know what this design looks like. I downloaded the zip file but it didn't have a graphic. From the description it sounds like a Daline.

Has anyone got a simple schematic?
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Old 15th June 2004, 10:48 AM   #32
Coolin is offline Coolin  Netherlands
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Default Blowing over a bottle.....

I think this is the underlying principle only larger.

I supose thats pretty effecient.

Coolin
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Old 15th June 2004, 11:11 AM   #33
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Default Re: Blowing over a bottle.....

Quote:
Originally posted by 7V
Sorry guys but I still don't know what this design looks like. I downloaded the zip file but it didn't have a graphic. From the description it sounds like a Daline.

Has anyone got a simple schematic?

Quote:
Originally posted by Coolin
I think this is the underlying principle only larger.

I supose thats pretty effecient.

Coolin
Hi Steve

I have not seen this design yet myself, but i will make one if a design is given, modern drive units have much larger cone travel from ones made lets say 30 years ago, this was a limiting factor in the design way back then,IMO I am sure it will be like a Daline or T-line but working on another wave lenght i hope! It should be very effecient, to make infrawaves part of the music. There is nothing more impressive when demonstrating a pair of speakers when a person really has there opened.
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Old 15th June 2004, 01:01 PM   #34
synergy is offline synergy  United Kingdom
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Quote:
Originally posted by 7V
Sorry guys but I still don't know what this design looks like. I downloaded the zip file but it didn't have a graphic. From the description it sounds like a Daline.

Has anyone got a simple schematic?
check out the patent link back one page (providing you can do pdf's that is)

quite a comprehensive set of drawings and explainations
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Old 17th June 2004, 07:37 AM   #35
fragma is offline fragma  South Africa
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Wink AT LAST - THE FULL DESIGN AS PROMISED

AT LAST,

I have completed the document. Pictures and all. Appologies for the large size of the document, but the diagrams need to be quite clear to figure out whats actually going on.

Best of Luck lads, and pls send me feedback on any developments or discoveries you might make.
Mail me on oiltanker@webmail.co.za

Best Regards
Ryan
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Old 17th June 2004, 10:26 AM   #36
fragma is offline fragma  South Africa
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Default GRAHAM HOLLIMAN PLANS

OK, It seems my plans of 750k are too big compared to the allowed limit of about 100k.
Does is there anyone that can send the plans to to post here in some way, or on some site?
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Old 17th June 2004, 04:10 PM   #37
qi is offline qi
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There are ten full pages in the patent with lots of detail (I initially missed that ... DOH!)

...from the patent
Attached Images
File Type: png gh05.png (8.9 KB, 1617 views)
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Old 18th June 2004, 10:42 AM   #38
synergy is offline synergy  United Kingdom
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Default not entirely convinced it does what it says on the tin

i'd welcome your thoughts on this but first off thanks for the plans Ryan, i've put them on some space if anyone wants them, save hassling you too much eh? - Holliman.zip

right i've done a rough number crunch and i stress this was just a rough one i didn't have the time last night to draw it into a cad program and get the exact measurements

not having the specs available for the specially designed drivers originally used and without mailing wilmslow audio and having to wait for a response i've used 3 different drivers as a comparison (all eminence it was easier) and put it into AkaBak (the only thing capable of simulating this)

anyways i'm not entirely convinced for starters the efficiency wasn't as high as i was expecting and the smoothest line gave a 12dB roll off from 50Hz which could easily be obtained with a sealed box

however the biggest shock and this might explain the poor sound at high volumes was that at 1W the cone excursion was already well over 3mm

now it's quite possible i've made a mistake somewhere but i don't think so having rechecked it this morning

obviously better drivers maybe out there with tweaks to suit but see for yourselves - Holliman Response

black line = Kappa 15LF
green line = Beta 15
blue line = Alpha 15

i think it's possible the theory is sound however the application of it is flawed because of driver limitations namely the excursion and rather than using a low excursion driver a high one might be best ie the lab12 might be a good one
i didn't model it cos it would've meant redoing the whole thing
i might do so later as i'm going to have a play around with the whole design anyways and i'll let you know my results


the other side of this is bar movies and their effects what medium actually produces signals below 20Hz?

i was always under the impression the vinyl was cut between 30Hz and 15KHz with CD's being 20/20

bottom A on a concert grand might be 27.5Hz but i'm not convinced we hear that more than we do its harmonics

if that's the case are people simply feeling nauseous to some humble deck rumble or spurious groove distortion?

dave
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Old 18th June 2004, 11:28 AM   #39
7V is offline 7V  United Kingdom
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I haven't had the time to look into this thoroughly yet but it may be that the Helmholtz resonator theory is close to the mark.

If so, I would guess that unless the box size is large, the Q of the resonator will be high, giving a very steep curve and a precise frequency that is 'amplified'. Either side of this frequency the response won't be so good.

Can anyone go further on the theoretical side of the design?
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Old 18th June 2004, 11:52 AM   #40
synergy is offline synergy  United Kingdom
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i've mailed wilmslow audio with a view of getting details of the original drivers or something that would be suitable
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