Lots of input while I've been away
Dave, the room gain can only be a good thing - I'm trying to set myself a "worse case scenario", and then over engineer anything I go for.. I'd like a comfortable 115Db for the peaks in movies, and feel that 4 drivers eq flat to 20Hz would be able to do this, if I measure the drivers before I build the transform circuit, I'm hoping only to need a handful of gain at lowest frequencies to make flat.
Brian,
I said "lowish" watts, and I should have given a figure - lets say around 32 watts - this gives your 160 shivas 135.24 Db !thats a huge amount!
I'm only sifting this through my mind at the mo, I've got to finish my present project, but you guys have given me lots of food for thought, and I appreciate it...
Thanks
Rob
Dave, the room gain can only be a good thing - I'm trying to set myself a "worse case scenario", and then over engineer anything I go for.. I'd like a comfortable 115Db for the peaks in movies, and feel that 4 drivers eq flat to 20Hz would be able to do this, if I measure the drivers before I build the transform circuit, I'm hoping only to need a handful of gain at lowest frequencies to make flat.
Brian,
I said "lowish" watts, and I should have given a figure - lets say around 32 watts - this gives your 160 shivas 135.24 Db !thats a huge amount!
I'm only sifting this through my mind at the mo, I've got to finish my present project, but you guys have given me lots of food for thought, and I appreciate it...
Thanks
Rob
Just ran my 4 scanspeaks 8565-01's that are going into my stereo speakers, and they've got a total (combined)vd of 858 cm3 - this is about 102Db at max excursion.(20Hz f-3)
I'm pretty happy with this, as real music would never have that much 20Hz present in it. Hopefully I'll be able to "linkwitz transform" these flat to 20Hz, and enjoy a nice full bass at a low distortion level.
I'll just add that I probably listen at well below reference levels aswell.
Unless I got me sums wrong, I'm looking forwards to getting these built.
Rob
I'm pretty happy with this, as real music would never have that much 20Hz present in it. Hopefully I'll be able to "linkwitz transform" these flat to 20Hz, and enjoy a nice full bass at a low distortion level.
I'll just add that I probably listen at well below reference levels aswell.
Unless I got me sums wrong, I'm looking forwards to getting these built.
Rob
from someone who has been downsizing....(i started out with 2 JBL 2245s, then used 4 Audio Concpets 12" and now intend to make do with 2 Eminence 8") rob, the SS bass definition should be much better than the 12 or 15" you are looking at.
having used big bass setups (the biggest being 6 12" corner loaded) what i find is that as you get real low in freq. you have all sorts of room node hell. everything in the room resonates sooner or later, windows, chandeliers, etc... and i went made controlling all these resonaces within the confines of WAF.
i live in a brick/RCC constrcuted apt. and given this enviroment a F3 of 40Hz with about 200cm3 of displacement is adequate for upto 100db. any more and WAF rears its ugly head and the other in animate objects start their music too. 200cm3 works out fine at a 8" with 1cm one way linear throw is perfect.
having used big bass setups (the biggest being 6 12" corner loaded) what i find is that as you get real low in freq. you have all sorts of room node hell. everything in the room resonates sooner or later, windows, chandeliers, etc... and i went made controlling all these resonaces within the confines of WAF.
i live in a brick/RCC constrcuted apt. and given this enviroment a F3 of 40Hz with about 200cm3 of displacement is adequate for upto 100db. any more and WAF rears its ugly head and the other in animate objects start their music too. 200cm3 works out fine at a 8" with 1cm one way linear throw is perfect.
Hi Navin,
I'll be using a dedicated room for this setup, and only be using the subs with movies. I'm not really into high volumes, just good extention. (I listen to hip hop, drum and bass as well as jazz, blues and acoustic) so low bass needs to be there.
I'm reckoning that the peerless xls' will be good enough to fill in the .1 on my surround system. Although they're about the same price as the scanspeaks, so if I like mine enough I could go for more of the same
As I said earlier, this is mainly musings at the moment.
If I'm lucky I won't even need to eq the scanspeaks!
I'm making the active x/o's without any baffle compensation, as I will measure the speakers in room, and put the compensation circuit on a different board. This way if I move house etc I only need to change the one board to set them up.
Cheers for the input
Rob
btw whats the RCC bit of brick/RCC ?
I'll be using a dedicated room for this setup, and only be using the subs with movies. I'm not really into high volumes, just good extention. (I listen to hip hop, drum and bass as well as jazz, blues and acoustic) so low bass needs to be there.
I'm reckoning that the peerless xls' will be good enough to fill in the .1 on my surround system. Although they're about the same price as the scanspeaks, so if I like mine enough I could go for more of the same
As I said earlier, this is mainly musings at the moment.
If I'm lucky I won't even need to eq the scanspeaks!
I'm making the active x/o's without any baffle compensation, as I will measure the speakers in room, and put the compensation circuit on a different board. This way if I move house etc I only need to change the one board to set them up.
Cheers for the input
Rob
btw whats the RCC bit of brick/RCC ?
Where does the extra 3dB come from?
Dickason talks about the efficiency gain from combining acoustic waveforms in his Loudspeaker Cookbook, and talks about the extra 6dB when two correlated signals are added together.
Double the power into a speaker and that normally gives you an extra 3dB. So the question in my curious engineering mind is "where does the extra 3dB efficiency gain come from?" Any thoughts?
Mick
Dickason talks about the efficiency gain from combining acoustic waveforms in his Loudspeaker Cookbook, and talks about the extra 6dB when two correlated signals are added together.
Double the power into a speaker and that normally gives you an extra 3dB. So the question in my curious engineering mind is "where does the extra 3dB efficiency gain come from?" Any thoughts?
Mick
RobWells said:Brian,
I said "lowish" watts, and I should have given a figure - lets say around 32 watts - this gives your 160 shivas 135.24 Db !thats a huge amount!
Indeed you are right, I was just referencing the equations in the shiva white paper, which is for 1W / 1m. You definately could use much less then 160 shivas.
I think that 160 shivas with a lot of amplification would cause instant brain damage and loss of hearing.
Good luck in your project. It will be interesting to see how this comes out.
--
Brian
daatkins said:
David,
This is what I have found so far: http://www.remo.nl/alcone-8.htm . It appears to be Klang & Ton measurements. I am a bit skeptical to the rest of their T/S parameter results but I assume they got voice coil height = 15 mm and gap height = 8 mm right by simple physical measuring. Now if the maximum linear excursion is calculated as (Hvc – Hg)/2 +Hg/4 where Hvc is voice coil height and Hg is gap height then Xmax comes out (15 – 8)/2 + 8/4 =5.5mm, which is OK for woofer but not so great for subwoofer. For greater Spl you need two woofers but looking at their manufacturer quoted Qts value =0.46 you will end up with quite large enclosure and its not mini- sub anymore.
Argo
RobWells said:Hi again Dave,
I was interested in the shiva, but I'm "pretty" sure its not availabe in the UK. The peerless definitely is (at a price
A list of worldwide dealers for the Shiva and other Adire products is given at their dealer list here:
http://www.adireaudio.com/dealers.htm
For Great Britain, here is the dealer:
GREAT BRITAIN
Design 3DW3
15 East Mearn Road
West Dulwich
London SE21 8HA
PHONE: 20 8670 3770
E-MAIL: jc@design3dw3.co.uk <mailto:jc@design3dw3.co.uk>
For all I know, that might not be the only dealer. They might be the distributor, who supply other dealers throughout the country. In my experience, most distributors are very happy to give the public the addresses and phone numbers of the dealers they supply.
If you do contact them, you might consider posting the price of the Shiva and the Tempest. They might be of some interest to other British DIYer's.
Good luck!
planet10 said:
I'm not really sure, Dave. I'm kind of drawn towards a 5-channel a/v power amp from one of the better brands. Tag Mclaren possibly? Or I could go for 2/3 stereo power amps up to the 60/80 watts mark - this would give me some headroom.
Kelticwizard, I've just e-mailed them to ask for the prices. I'll post here if I get a reply.
Navin - "now i am getting jealous with you having dedicated rooms and all that"
It's only 1 room, and as I don't have kids my wife suggested using the 2nd bedroom as a lounge, leaving the main lounge/diner for my listening room/home theater. I guess I'm a lucky man
Cheers for now
Rob
RobWells said:
I've heard good things about the TAG/McLaren, and i know the Linn is nice, but those don't provide any amplification for the sub (the Linn doesn't).
I mangaged to score myself one of the Techics stand-alone processors and am always using a mismash of amplifiers. 2xNAD 7020 on the surrounds & sub, and a NAIM 160 on the mains (or at least will be once it is set back up). Everyything is always subject to change.
dave
""I've heard good things about the TAG/McLaren, and i know the Linn is nice, but those don't provide any amplification for the sub (the Linn doesn't).""
Tag do a 5-channel power amp to match their processors(100x5R poss.?). Linn do a few power amps, the lk100 is a fairly cheap used (2 channel) @30watts (IIRC)
Tag, lexicon and meridian lead the stakes in the processor races.(over here at least)
These musings have already spent about 6 months worth of next years savings
Rob
Tag do a 5-channel power amp to match their processors(100x5R poss.?). Linn do a few power amps, the lk100 is a fairly cheap used (2 channel) @30watts (IIRC)
Tag, lexicon and meridian lead the stakes in the processor races.(over here at least)
These musings have already spent about 6 months worth of next years savings
Rob
RobWells said:
The one i was thinking of was the classic -- DVD/Radio/Pre/Processor/5x50 -- all in 1 box.
An externally hosted image should be here but it was not working when we last tested it.
dave
I missed the 5x 50...sorry!(shows I'm not really up on av!- all I'm bothered about is dd 5.1 and dts, ex etc is a pleasant extra)
Looks really nice, trouble is my main L/R need 4 amps (when they're built), and my main source is my linn sondek lp12 (bought about 5 cd's in last 3 years against 100+ Lp's.
Also I use htpc for dvd's (barco 800 pj) and the dvd drive would be wasted ! _ radio is taken care of by satellite, leaving a pre/processor that needs an extra 4 amps to get going..
The way I'm looking at going is having an input selecter on the active x-over to select between stereo pre-amp and av pre amp. This allows me to play with valve pre's for the sondek/cd, and use the av for dvd, pc games, console games, sattelite tv and radio (plus my minidisc recorder, tape deck and the 78rpm record deck I'm looking for for my wife's nans collection that goes back to the 40's. (including chuck berry, lonny donnegan, eartha kitt etc..)
Also means I can use my yamaha av amp as a pre to get me going, and upgrade as and when funds allow.
Cheers
Rob
Looks really nice, trouble is my main L/R need 4 amps (when they're built), and my main source is my linn sondek lp12 (bought about 5 cd's in last 3 years against 100+ Lp's.
Also I use htpc for dvd's (barco 800 pj) and the dvd drive would be wasted ! _ radio is taken care of by satellite, leaving a pre/processor that needs an extra 4 amps to get going..
The way I'm looking at going is having an input selecter on the active x-over to select between stereo pre-amp and av pre amp. This allows me to play with valve pre's for the sondek/cd, and use the av for dvd, pc games, console games, sattelite tv and radio (plus my minidisc recorder, tape deck and the 78rpm record deck I'm looking for for my wife's nans collection that goes back to the 40's. (including chuck berry, lonny donnegan, eartha kitt etc..)
Also means I can use my yamaha av amp as a pre to get me going, and upgrade as and when funds allow.
Cheers
Rob
RobWells said:
A nice solution but not for you
What LP12 rig do you have? (i've owned something like 14 of them -- audiophilia nervosa).
Jeez, i've amassed my entire 30 CD library in the last 3 years (except for special ones -- like Viktor Lazlo) i limit myself to $2 CAD/CD. And LPs, only a 100. I've only bought a handful or 2 new ones but it is a rich time for the used album -- i'll probably get a couple hundred good albums out of the couple thousand i've scooped up in the last year or so (net cost of under a Loon each). And the album covers from the rejects make good packing material.
dave
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