Graham Holliman Velocity Coupled Infra Bass Speaker? - diyAudio
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Old 22nd April 2002, 08:51 PM   #1
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Question Graham Holliman Velocity Coupled Infra Bass Speaker?

Has anyone here heard about the Graham Holliman Velocity-Coupled Infra-Bass Speaker? If is a very old design but a very efficient VERY low sub woofer box. I discovered the plans a while back and I dont know what driver to use. In the plans they say there is a LED circuit also to indicate the presence of infra bass activity (potentially dangerous!!). The crossover is also mentioned but the diagram of specifications are not given. I am trying to keep this as original as possible so if anyone has any of this information or has every heard of this design please let me know.
Thanks
Neopsp
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Old 23rd April 2002, 07:00 PM   #2
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Wow, I haven't heard about this speaker in a very long time. I was never convinced of the merits, or explanation given, of the technology, but i do have a copy of the patent somewhere in the depths of my files.
I do not believe the claims of high efficiency bass from small enclosures that many people tout. These claims are rarely substantiated.
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Old 23rd April 2002, 08:52 PM   #3
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I made contact with someone that has build the speaker and even has a letter from Graham Holliman. He was not to impressed by the Sub either. He said it was very boomy. I want to build this sub out of curiosity anyway . I am thinking of saving up for the Shiva 12" driver for such a project. What do you people think? When I oneday get enough money together and get the time (not within the next 3 months ) I will post what it sounds like.
Thanx
Neopsp
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Old 23rd April 2002, 08:58 PM   #4
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I recall something in "Hi-Fi Answers" mag in the mid 70's by the author but it wasn't small. It used a 15 or 18" Atlas driver from the UK specialist speaker maker Richard Allan Radio Ltd. I suggest you get in touch with Haymarket Publishing, London UK. They published a swag of Hi-Fi mags in the 70's of which Hi-Fi Answers was just one. These titles over the years eventually got rolled into one that is published today as "What Hi-Fi". If you are lucky they may still have something on file...
tomcat
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Old 9th June 2004, 10:15 AM   #5
fragma is offline fragma  South Africa
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Thumbs up Tried and Tested the Graham Holliman

Hi there, I see the posts here are rather old, however i did build the 10" unit and there are some very interesting things i found.
1. The box is very room fussy. The room needs a sealed room. Closed doors, and windows. In an open plan lounge kitchen etc, you wont even notice it. However if you do have a sealed room, preferably with a cement roof, floor, it will blow your mind.
2. It has to be coupled out of phase to your normal speakers. Positive to negative, and negative to positive. The output sound is 180 out of phase, and hence requires this.
3. The louder you play the speaker, the worse it sounds. Its extremly efficient in my opinion, and in the right room, even tapping on the back of the speaker cone, the room shakes. So...
4. ...in my opinion, a stiff cone, and a powerful amp are in order. The less the cone moves with low frequencies, the better the sound. If you turn it up with low fr's, it just flutters with the speaker struggling to get to its excursion limits.
5. Hence the reason why some ppl call it boomy...if its not in the right room, you just hear a little bit of a boom....nothing more.
6. However, in the right room, of which i have found only two...(my parents lounge,and in a student commune. The room was all cement, about 7meters X 7 meters, cement floor, and roof, and 2 sliding doors. All closed of course.
Even at 9 o clock on the amp dial of a cheap kenwood mini system concected in parrallel passive to one of the outputs, playing a pipe organ recording...my eyes were almost coming out of their sockets. As for purity, the deep tones were so distinct you could hear the individual beats of the low fr's. I could almost feel the air it was so thick. Its the lowest sub ive ever heard, and no one has ever demonstrated otherwise to me....not even on a $2500 active sub.
7. One drawback however is the very noticable gap between your 40Hz floor standers and the point where this sub starts breathing...at around 25Hz and down. You need a conventional sub to fill the gap. This design is for Extremely low fr's.
8. The danger to property and health...its true. After spending 2 hours on optimal placement, i had to take a break for 2 days. I had neck pain, and dizziness. (a number of times)
9. You REALLY do hear incredible sounds like mic bumps through the amp of a live recordding like Eric claptons unplugged. Song number 4, (12 or 10) on Enyas watermark, and few others...not many.
In Enya number 4, there is a sub fr undertone of around 15Hz the entire song that you cant hear on a conventional system. However, half way through the song you need to turn it down ....its too much to bear, but serves as a great demo.
10. Crossover, and driver. Well, at the time of building, i used an old cheapo Vifa 80W 10" driver, no crossover, and passive into that cheap kenwood Hi-fi, and that nearly blew me away even on a low volume. I fear anything more powerful than that!!!!!!!!!!!
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Old 9th June 2004, 03:46 PM   #6
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What's a Graham Holliman?

Your post is standing alone where it seems that it was meant to be part of an existing thread.
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Old 10th June 2004, 07:38 AM   #7
fragma is offline fragma  South Africa
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Thumbs up Tried and Tested the Graham Holliman

Hi there, I see the posts here are rather old, however i did build the 10" unit and there are some very interesting things i found.
1. The box is very room fussy. The room needs a sealed room. Closed doors, and windows. In an open plan lounge kitchen etc, you wont even notice it. However if you do have a sealed room, preferably with a cement roof, floor, it will blow your mind.
2. It has to be coupled out of phase to your normal speakers. Positive to negative, and negative to positive. The output sound is 180 out of phase, and hence requires this.
3. The louder you play the speaker, the worse it sounds. Its extremly efficient in my opinion, and in the right room, even tapping on the back of the speaker cone, the room shakes. So...
4. ...in my opinion, a stiff cone, and a powerful amp are in order. The less the cone moves with low frequencies, the better the sound. If you turn it up with low fr's, it just flutters with the speaker struggling to get to its excursion limits.
5. Hence the reason why some ppl call it boomy...if its not in the right room, you just hear a little bit of a boom....nothing more.
6. However, in the right room, of which i have found only two...(my parents lounge,and in a student commune. The room was all cement, about 7meters X 7 meters, cement floor, and roof, and 2 sliding doors. All closed of course.
Even at 9 o clock on the amp dial of a cheap kenwood mini system concected in parrallel passive to one of the outputs, playing a pipe organ recording...my eyes were almost coming out of their sockets. As for purity, the deep tones were so distinct you could hear the individual beats of the low fr's. I could almost feel the air it was so thick. Its the lowest sub ive ever heard, and no one has ever demonstrated otherwise to me....not even on a $2500 active sub.
7. One drawback however is the very noticable gap between your 40Hz floor standers and the point where this sub starts breathing...at around 25Hz and down. You need a conventional sub to fill the gap. This design is for Extremely low fr's.
8. The danger to property and health...its true. After spending 2 hours on optimal placement, i had to take a break for 2 days. I had neck pain, and dizziness. (a number of times)
9. You REALLY do hear incredible sounds like mic bumps through the amp of a live recordding like Eric claptons unplugged. Song number 4, (12 or 10) on Enyas watermark, and few others...not many.
In Enya number 4, there is a sub fr undertone of around 15Hz the entire song that you cant hear on a conventional system. However, half way through the song you need to turn it down ....its too much to bear, but serves as a great demo.
10. Crossover, and driver. Well, at the time of building, i used an old cheapo Vifa 80W 10" driver, no crossover, and passive into that cheap kenwood Hi-fi, and that nearly blew me away even on a low volume. I fear anything more powerful than that!!!!!!!!!!!

HOWEVER, I would like to see detailed instructions on the driver types to use(Long excursion speakers or very stiff types), how to mount the driver unit (whether you use spacers or just bolt it down), and any other tips, i.e. (crossover circuits, fr's etc.)


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Old 10th June 2004, 07:50 AM   #8
fragma is offline fragma  South Africa
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Default Sorry about that...

Hi Bill,

Sorry about that, Im new to the forum, so instead of clicking reply to thread, i created a new one. It was meant to go under the Graham Holliman bass enclosure some guys were talking about. If you search on google for "graham holliman" youll find the threads.

A bit more about it. Its called the Graham Holliman Velocity Coupled Infra Bass Speaker. Its an enclosure design from the year dot. Its very complex to build, but if you do a bit of diy, its not so difficult. I built the 10" version, but you can build the 12" or 15" design. Its an enclosure that works very differently from normal subs in that it increases and decreases the overall pressure of the listening room to achieve a bass response like you cannot believe. However, if you read (and you did) my response, it hence needs to be in a room, with all the doors shut, and windows shut to get the full effect. Open plan house just wont work at all. The lowest fr's im convinced i heard was in a room about 7mX7mX3m, cement roof, and floor...and simply plugged it into a mini system passivly (no filters, or amps) to the right channel (remember it must be connected wrong way around to work) and boy...i thought the space shuttle was taking off. Its not a sub you blast power into in my opinion, its so efficient, it takes a minute amount of power to reproduce VERY low fr's

The design notes claim it extends from 5Hz-25Hz. Yes...thats 5!!
Now shoot me if im wrong, but im sure ive heard mine go as low as about 12-15Hz, and i built the baby one!!!

If you dont hear low fr's immediatly even at low volumes, then the room is wrong....its room fussy to the extreme!
If you want the designs i have them on hard copy, i can scan them if you interested.

regards
ryan
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Old 10th June 2004, 02:32 PM   #9
Coolin is offline Coolin  Netherlands
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Default If your not joking...

I'd like the designs you have please...

thanks,

Coolin
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Old 10th June 2004, 02:37 PM   #10
dhenryp is offline dhenryp  United States
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So how about a picture or a link to more detailed description/plans.
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