I have got the chance to buy some "new" 12" bass drivers for £15.00 each with the following spec. Paper cone, double magnet;
3.2 ohm's
95 db/w
27.4 Fs
Qms 2.34
Qes 0.26
Qts 0.24
VAS 268 litre's
SD 514 cm squared
What do you think?
Sealed/Ported......... I thought that I would get 4 of them.
Hi Jerryo,
Looks like very good drivers. Although no x-max is given: At 1 W input using 4 of those drivers would surely shake my room wall if I had the opportunity to design suitable speakers.
I would build a Ht-woofer system comprising of 2 serial connected ported boxes in parallel with a T-TQWT driven by a ordinary sub bass amp.
Place the T-TQWT somewhere at the short room sides and the ported boxes spread out at both of the longer wall sides and test for best in room response.
If you aim for a isobaric or clamshell,minimum volume ported box using 4 drivers ,you could put them in the reflex box shown submitted, but the in room SQ will IMO be far below what's achievable with the T-TQWT and the 2 ported boxes.
PS: The T/S data is consistency checked using the HR input screens.
b
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Hi bjorno,
thank you for your reply; yet again you have shown how generous you are with your time by answering questions posted by less informed people like myself.
From what you say these drivers will be a good buy so I will probably go ahead and get them.
I will have to accept certain design restrictions to placate my wife so compactness of the box will have to be considered.
Would I have any success with a ported isobarically loaded configuration? Isobarik just to reduce VAS if for no other reason.
I have no doubt that the ideas you relayed to me would be very, very good but at the moment I think they may be just a bit beyond my available time and circumstances.
Thank you again
Jerry
thank you for your reply; yet again you have shown how generous you are with your time by answering questions posted by less informed people like myself.
From what you say these drivers will be a good buy so I will probably go ahead and get them.
I will have to accept certain design restrictions to placate my wife so compactness of the box will have to be considered.
Would I have any success with a ported isobarically loaded configuration? Isobarik just to reduce VAS if for no other reason.
I have no doubt that the ideas you relayed to me would be very, very good but at the moment I think they may be just a bit beyond my available time and circumstances.
Thank you again
Jerry
Hi Jerry,
Why not state your requirements on the speaker box dimensions from the beginning?
Who knows but you?
..Isobarik just to reduce VAS if for no other reason..
Jerry
Are you sure? : http://www.musicanddesign.com/Isobaric.html
b
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Hi bjorno,
that's an interesting study of isobaric loading; I wonder if anyone at Linn products has read it? I have found that isobaric loaded B139's produce some very deep and convincing bass. The distortion mechanism's mentioned are no doubt real but with the distortions of room acoustics they are probably not that important. But then i know nothing.
I do not know what size cabinet is going to be acceptable to my wife. I think perhaps I will never know until the speakers are placed into the room. I guess the phrase "as small as possible" would be on my wifes lips (as if that means anything)
I re-read some threads regarding "ripoles" recently and to be honest because of the simplicity of construction I might, just for the hell of it try them out. They do at least offer the smallest box configuration and if they don't work out as I imagine then not alot of material or time will have been wasted.
I can then move on upwards to more elaborate designs as necessary.
Cheers friend
that's an interesting study of isobaric loading; I wonder if anyone at Linn products has read it? I have found that isobaric loaded B139's produce some very deep and convincing bass. The distortion mechanism's mentioned are no doubt real but with the distortions of room acoustics they are probably not that important. But then i know nothing.
I do not know what size cabinet is going to be acceptable to my wife. I think perhaps I will never know until the speakers are placed into the room. I guess the phrase "as small as possible" would be on my wifes lips (as if that means anything)
I re-read some threads regarding "ripoles" recently and to be honest because of the simplicity of construction I might, just for the hell of it try them out. They do at least offer the smallest box configuration and if they don't work out as I imagine then not alot of material or time will have been wasted.
I can then move on upwards to more elaborate designs as necessary.
Cheers friend
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