Hi Angshu
Ask an updated carpenter. Their are many of them who nowadays do lot of new stuff. Or if you have a Gautier showroom nearby, ask them. 3-4 mm is very small i think.
Navin
Check ur mail dude. Its increasingly looking like LH757 on 30th for me. If u r in the same bird then perhaps we can both indulge in the the happy things at kaiser strasse in FRA on sat night.😎
Ask an updated carpenter. Their are many of them who nowadays do lot of new stuff. Or if you have a Gautier showroom nearby, ask them. 3-4 mm is very small i think.
Navin
Check ur mail dude. Its increasingly looking like LH757 on 30th for me. If u r in the same bird then perhaps we can both indulge in the the happy things at kaiser strasse in FRA on sat night.😎
corbato,
i still have not got my passport. the police have no news about it either. lets see. april 27th even i will know. ping me then.
about the drivers the 20cm one does not look too bad. the Vas is quite small. However with the high Qts a aperiodc box might be the answer.
any idea about Bl, Xmax, Mms?
i still have not got my passport. the police have no news about it either. lets see. april 27th even i will know. ping me then.
about the drivers the 20cm one does not look too bad. the Vas is quite small. However with the high Qts a aperiodc box might be the answer.
any idea about Bl, Xmax, Mms?
T/S Parameter for Indian Drivers
Navin,
Here is the complete T/S parameter for Bolton 20LPW22. These measurements were taken a while ago on a different driver.
BOLTON 20LPW22
Sd.........214.0 cm^2
Vas........60 L
Cms........9.358e-04 m/N
Cas.........4.286e-07 m^5/N
Qms........4.18
Qes.........0.85
Qts..........0.71
Re...........6.8 ohm
Le...........0.715 mH
Mmd.........24.66 g
Mms.........26.63 g
Fs.............32 Hz
Bl..............6.52 N/A
Xmax..........6 mm
Cheers
Angshu
Navin,
Here is the complete T/S parameter for Bolton 20LPW22. These measurements were taken a while ago on a different driver.
BOLTON 20LPW22
Sd.........214.0 cm^2
Vas........60 L
Cms........9.358e-04 m/N
Cas.........4.286e-07 m^5/N
Qms........4.18
Qes.........0.85
Qts..........0.71
Re...........6.8 ohm
Le...........0.715 mH
Mmd.........24.66 g
Mms.........26.63 g
Fs.............32 Hz
Bl..............6.52 N/A
Xmax..........6 mm
Cheers
Angshu
does not look too bad. is it stamped frame? well even if it is we can modify that cant we? 🙂
can these specs be trusted? even then as long as the variations are not too off they can be used in an aperodic box.
what do they cost?
where in bombay can i get them?
can these specs be trusted? even then as long as the variations are not too off they can be used in an aperodic box.
what do they cost?
where in bombay can i get them?
T/S parameter for Indian drivers
I will try and take some measurements this weekend.
The 20LPW22 costs around Rs600, and should be easily available in Lamington road. If you cannot get it there let me know and I will ask the old man for his dealer's address in Bombay.
Angshu
I will try and take some measurements this weekend.
The 20LPW22 costs around Rs600, and should be easily available in Lamington road. If you cannot get it there let me know and I will ask the old man for his dealer's address in Bombay.
Angshu
Hi all,
I tried to measure the T/S specs of a Bolton driver (20SJW22, a pp-cone 8" sub(?)) using the methods given on Rod Elliot's website (sound.westhost.com, I think) and got some values that were very strange indeed, like negative Vas. Then again, it was done in a hurry, without proper sealing of the measurement box. Could someone give me an idea of how to do this? I remember reading somewhere that you can attach weights to the cone instead of mounting it on a sealed wooden box. I'd be glad if someone could give me some tips on this method, such as how much weight should I use (for a driver of the size mentioned). Thanks in advance.
Has Peerless India stopped using the "stars" logo of Peerless Denmark? I recently bought a pair of 5.25" woofers (for a 2-way multimedia speaker) which did not bear this logo. It had the typical "shiny paper" finish of other Peerless drivers I've seen on the net. No time to try and measure T/S params on those two.
I tried to measure the T/S specs of a Bolton driver (20SJW22, a pp-cone 8" sub(?)) using the methods given on Rod Elliot's website (sound.westhost.com, I think) and got some values that were very strange indeed, like negative Vas. Then again, it was done in a hurry, without proper sealing of the measurement box. Could someone give me an idea of how to do this? I remember reading somewhere that you can attach weights to the cone instead of mounting it on a sealed wooden box. I'd be glad if someone could give me some tips on this method, such as how much weight should I use (for a driver of the size mentioned). Thanks in advance.
Has Peerless India stopped using the "stars" logo of Peerless Denmark? I recently bought a pair of 5.25" woofers (for a 2-way multimedia speaker) which did not bear this logo. It had the typical "shiny paper" finish of other Peerless drivers I've seen on the net. No time to try and measure T/S params on those two.
1. yes peerless has stopped using the danish logo
2. there are 2 methods i know of to measure t/s specs added mass and fixed volume. i find added mass easier as one does not need to build a box.
the added mass i use is pieces of blutak stuck the the dust cap.
you have to break in the driver before you do this. the fast way is to run 5 W at Fs for 30 mins. I know there is a faster way but i cant think of it right now.
2. there are 2 methods i know of to measure t/s specs added mass and fixed volume. i find added mass easier as one does not need to build a box.
the added mass i use is pieces of blutak stuck the the dust cap.
you have to break in the driver before you do this. the fast way is to run 5 W at Fs for 30 mins. I know there is a faster way but i cant think of it right now.
Roadkill
You can download this Driver Parameter Calculator freeware which gives extensive information of how to measure T/S parameters.
http://home10.inet.tele.dk/cfuttrup/dpc049.exe
I have always wondered which is the best method to calculate Vas, closed box or added mass. though added mass is easier, you don't need a test box, but it can give inaccurate results because you cannot determine Sd accurately with a ruler. Little changes in the dia reflects a large change in Vas. I use a Rs 5 coin as it weighs 10gms. You can get it weighed accurately in a jewelers scale.
For Vas I personally use Robert Bullocks method which uses a test box with a port, but I suggest you read through the DPC documentation first. It is quite extensive.
Hope this helps.
Angshu
You can download this Driver Parameter Calculator freeware which gives extensive information of how to measure T/S parameters.
http://home10.inet.tele.dk/cfuttrup/dpc049.exe
I have always wondered which is the best method to calculate Vas, closed box or added mass. though added mass is easier, you don't need a test box, but it can give inaccurate results because you cannot determine Sd accurately with a ruler. Little changes in the dia reflects a large change in Vas. I use a Rs 5 coin as it weighs 10gms. You can get it weighed accurately in a jewelers scale.
For Vas I personally use Robert Bullocks method which uses a test box with a port, but I suggest you read through the DPC documentation first. It is quite extensive.
Hope this helps.
Angshu
well normally i use the Sd provided by the manufacturer. i wonder if the coin would rattle but blu tak can be made to any weight. do you add the weight to teh cone or to the dust cap?
I attach the coin to the dustcap with a spot of quickfix. Blutack is better, I am not sure whether the local jeweler will be happy to weigh it for me...just joking.
Thanks all, for the suggestions. I will try out the added weight method using a coin, I'm at a loss because I dont know what blu-tack is. I will try DPC. I really hope the Peerless drivers I bought are good ones (I forgot the shop name, it was on Lamington road, on the 1st floor of a building. Their shop board had "Peerless" clearly written there). If someone could name a dealer there (or better yet, in Bangalore or Chennai) who is reliable,that would be nice.
blutak is an australian product looks like plasticine. maybe a google search will tell you more. i get it at a local imported goods store in bombay.
i am too looking for a reliable dealer in mumbai (bombay). Chowdry trading is not as reliable as it was in the late 70s.
i am too looking for a reliable dealer in mumbai (bombay). Chowdry trading is not as reliable as it was in the late 70s.
You are bound to find Blutak in any good stationary or home store in Bangalore. It is known as re-usable adhesive. It is also available as Wonder Tack marketed by Arcus ltd. 8, Camac Street, Kolkata-700017. 50gms cost Rs 60.
I have bought Peerless stuff from Chowdhry Trading in Lamington road. Are there any other dealers. Peerless India only pointed me to Chowdhury Trading. The problem is the model number they carry does not match the International Peerless numbers.
Any one used Dainty drivers in India.
Cheers
Angshu
I have bought Peerless stuff from Chowdhry Trading in Lamington road. Are there any other dealers. Peerless India only pointed me to Chowdhury Trading. The problem is the model number they carry does not match the International Peerless numbers.
Any one used Dainty drivers in India.
Cheers
Angshu
peerless sent me to chowdry too. in the old days chowdry used to carry philips and bolton. the bolton cones i did not like. they were ployprop and were heavy. i have never liked poly cones the papaer cones (doped) are usually better.
Ramesh trading corp used to carry drivers too as did pioneer. i am not sure today. i can find out on july 3-4 once i get back to bombay. email me then.
Ramesh trading corp used to carry drivers too as did pioneer. i am not sure today. i can find out on july 3-4 once i get back to bombay. email me then.
Navin
Dude I'm back. Are you accessing your vsnl account? I need to send you some pics.
Angshu
Great posts. Is the old man (chopra??) of Bolton still active? Ask him why Bolton doesn't make it anymore the way they used to in early 70's.
Dude I'm back. Are you accessing your vsnl account? I need to send you some pics.
Angshu
Great posts. Is the old man (chopra??) of Bolton still active? Ask him why Bolton doesn't make it anymore the way they used to in early 70's.
i am in LA. yes i manage via webamil. I had signed on for internet roaming but it dont work. i will have to chew out vsnl when i get back. right now i use AOL to access the net then use webmail to get vsnl.
angshu is totally great. i think those 8" bolton drivers might be the answer for a cheap sub. i intend using 4 x 8" in push-pull or push-push.
however now i am on another kick. i was at the hi fi show in Neu Isenberg (May29-June1st) and saw the Gradient speaker. a small italian marque with a dipole using 2 x 12". it was very impressive. I might try to replicate that using 3 x 8" or even 4 x 8".
too bad i could not find to see the CES at SF (june 5-9). as things go i will be back july 3-4.
hey guys there was nothing that was spectacular at the either show so dont feel left out. i have been to a lot of these and DIY is way ahead of these guys. With all the tools the pros have you'd think they'd do beyond puttting 3-4 cones in a box.
the best part of teh German show.
Fink Audio Consulting had some nice measuring and anlysis software (it could measure distotion v/s Bl, Distortion v/s Xmax etc and even ananlyse cone movement and distotion in the freq. domain and time doamin based on cone flex etc...Spent most of one morning playing with this (under the watchful eye of Karl Heinz Fink).
from what i hear teh SF show was a sad rerun of the NY show at Hilton last year. coming so close on the heals of the German show it left most of the small guys gasping to keep up.
angshu is totally great. i think those 8" bolton drivers might be the answer for a cheap sub. i intend using 4 x 8" in push-pull or push-push.
however now i am on another kick. i was at the hi fi show in Neu Isenberg (May29-June1st) and saw the Gradient speaker. a small italian marque with a dipole using 2 x 12". it was very impressive. I might try to replicate that using 3 x 8" or even 4 x 8".
too bad i could not find to see the CES at SF (june 5-9). as things go i will be back july 3-4.
hey guys there was nothing that was spectacular at the either show so dont feel left out. i have been to a lot of these and DIY is way ahead of these guys. With all the tools the pros have you'd think they'd do beyond puttting 3-4 cones in a box.
the best part of teh German show.
Fink Audio Consulting had some nice measuring and anlysis software (it could measure distotion v/s Bl, Distortion v/s Xmax etc and even ananlyse cone movement and distotion in the freq. domain and time doamin based on cone flex etc...Spent most of one morning playing with this (under the watchful eye of Karl Heinz Fink).
from what i hear teh SF show was a sad rerun of the NY show at Hilton last year. coming so close on the heals of the German show it left most of the small guys gasping to keep up.
My views on indian drivers
I would like to post my views on indian drivers. I have built a two way floorstander with 8" Bolton IMW series (Rs 820 each)and Philips silk dome tweeters (Rs 250 each), 18 MM MDF sealed unit completely filled with polywool. The unit stands at 36 inches, depth of 12 inches and width of 10 inches. Internal volume is around 2 cu ft.
They sound crap with off the shelf two way crossover.
I have two choices now:
1> To discard the whole units and start with something like the D3 at speakerbuilder.net
2>Keep the cabinet and replace the two drivers with Dayton 8" and silk dome at parts express.
Any other ideas are welcome.
I have yet to give up on the drivers but my advice is to stay clear of indian drivers. Manufactureres probably do not measure T/S params and so never publish. One can't really control entities one cannot measure. AVMAX (june 2003) issue has an ad from TORVIN selling individual drivers but looked to me that they are for car audio only. Anyhow someone on this thread wrote that drivers are indeed sold by torvin. I plan to write and get the prices. I just hope that they do not turn out to be another peerless india. They never bothered to reply to my inquiry about their drivers. One place for good drivers I know is Partsexpress.com. Just look at the VIFA drivers which are on sale.
One can find someone in the software industry and ask him to get some of the drivers. Software engineers travel quite often to the US.
By the way Paleasha's 12" sub has got good reviews with AVMAX. How about getting the driver as a spare. Do let me know if one can find the address. I am based in Bangalore. Do let me know if some one is coming to AV EXPO at Le Meridian on Sunday
I would like to post my views on indian drivers. I have built a two way floorstander with 8" Bolton IMW series (Rs 820 each)and Philips silk dome tweeters (Rs 250 each), 18 MM MDF sealed unit completely filled with polywool. The unit stands at 36 inches, depth of 12 inches and width of 10 inches. Internal volume is around 2 cu ft.
They sound crap with off the shelf two way crossover.
I have two choices now:
1> To discard the whole units and start with something like the D3 at speakerbuilder.net
2>Keep the cabinet and replace the two drivers with Dayton 8" and silk dome at parts express.
Any other ideas are welcome.
I have yet to give up on the drivers but my advice is to stay clear of indian drivers. Manufactureres probably do not measure T/S params and so never publish. One can't really control entities one cannot measure. AVMAX (june 2003) issue has an ad from TORVIN selling individual drivers but looked to me that they are for car audio only. Anyhow someone on this thread wrote that drivers are indeed sold by torvin. I plan to write and get the prices. I just hope that they do not turn out to be another peerless india. They never bothered to reply to my inquiry about their drivers. One place for good drivers I know is Partsexpress.com. Just look at the VIFA drivers which are on sale.
One can find someone in the software industry and ask him to get some of the drivers. Software engineers travel quite often to the US.
By the way Paleasha's 12" sub has got good reviews with AVMAX. How about getting the driver as a spare. Do let me know if one can find the address. I am based in Bangalore. Do let me know if some one is coming to AV EXPO at Le Meridian on Sunday
i do have plans to visit the expo....
time not yet decided....lil work pressure...!
btw is it only on sunday...!!??
time not yet decided....lil work pressure...!
btw is it only on sunday...!!??
u work on sunday????
you can contact mahendra palesha he is based in poona. if i was in bombay i could give you his contact but avmax might be able to help. MP is quite a nice guy. he has atleast 2 testing setups. the drivers are imported (you can read bet. the lines).
indian drivers have given me plenty of heartaches. the onlyones that were any good were the Philips dirvers in the 70s. they had a full range at one time. 12" 8" 5" mid, 2" dome mid, 2" cone tweeter, 1" dome tweeter (2 types). I wont waste badnwidth quoting model numbers but there are posts out there that have this info.
cheers.
you can contact mahendra palesha he is based in poona. if i was in bombay i could give you his contact but avmax might be able to help. MP is quite a nice guy. he has atleast 2 testing setups. the drivers are imported (you can read bet. the lines).
indian drivers have given me plenty of heartaches. the onlyones that were any good were the Philips dirvers in the 70s. they had a full range at one time. 12" 8" 5" mid, 2" dome mid, 2" cone tweeter, 1" dome tweeter (2 types). I wont waste badnwidth quoting model numbers but there are posts out there that have this info.
cheers.
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