I need to beef 2-3db from 18w9545

elviukai · 8th March 2006, 08:03 PM

hi, I am thinking to add magnet to scan spek 18w9545. it has 88-88.5db I REALLY need at least gain 3%

it plays in 8ltr ported box how will change vas,qts and other pr.
the box volume is stricly limitation of 7-9ltr

thank in advance//

elviukai · 9th March 2006, 10:18 AM

anybody?

sreten · 9th March 2006, 11:43 AM

Hi,

Vas, Qms and Fs will not change.

You can estimate the change in Qe (and thus Qts) by messing around
in WinISDPro, decresing Qe until you get the efficiency you want, or
plug in the efficiency you want and let it work out Qe and Qts.

I presume you want to gain 3dB not 3%, (or do you want 3% real efficiency ?)

/sreten.

elviukai · 9th March 2006, 03:04 PM

hi thanks for the answer, I want to increase in 3db from 88db/w/m to 90-91db. that would be probably 3% gain in Bl force factor if I am not mistaken. is it posible to achieve 90-91db with extra magnet. as I understand one direction it woulkd be semi shielded and another direction increase BL and thus sensitivity? or I am mistaken? shame to say but I have never played with theese extra magnets and dont know anything

and what size and lenght magnet should be, maybe two extra magnets will do better. somehow I pesimistic about gain 3db from 18w9545-02.. it already have 88.5db.w.m and 120mm magnet. and BL is 8.5-9. anyone played with added magnets?

sreten · 9th March 2006, 04:41 PM

Hi,

the mystery is why do you need 3dB extra ?

Probably there is a much easier solution.

sreten.

PS edit:

Quote:

adding 47Ohm resistors in series to tweeter improoves low frequency response!!

Whilst true it doesn't do much for sensitivy, distortion or help high Q tweeters !

elviukai · 9th March 2006, 05:05 PM

there is no mistery -I am doing wilson audio(alreday alsmost done) watt puppy 6 clone. not similar speaker or look like WA system 7 but exact . exact enclosures size and volume, exact weight(last was very hard job, used materials which is very good for damp[ing but not for health) grils, labels . - exact speakers. and 90% close to original series filter, I alreday get the same FR , phase xover points all I need is increase midrange sensitivity 3db. now I use L pad 4db for tweeters and 2.7ohm in series with woofers. to decrease woofers sensitivity is not very good idea. it tooked alsmost year to colect technical info about this speaker and spend lot of money for original dedicated midrange drivers (taken from wilson Benech 10 000eur speakers)

the speakers itsel has increribly speed and power,slamm from such a big and weight woofers and especialy midrange. . but sensitivity is 87db. too low to folow originals. so here is all story..

so only way is to beef up 3db from midrange

adding 47Ohm resistors in series to tweeter improoves low frequency response!!

this one was a joke

sreten · 11th March 2006, 02:29 PM

Hi,

well using a autotransformer on the mid is a possibility, but
you'd have to scale the crossover component values to suit.

The consequence would lower impedance over the midrange,
but you should get a similar voltage sensitivity, dB/2.83V.

/sreten.

Nemophyle · 11th March 2006, 02:39 PM

i'm really interrested into this also ...

i have a couple of magnet i could use for testing, but i would need information about how to proceed.

I could then do some T/S tests and see how the parameters changes

elviukai · 11th March 2006, 06:50 PM

what is autotransformer?

are you suggesting to conect some thing to lower impedance of midrange?

infinia · 12th March 2006, 01:17 AM

Wilson audio used OEM drivers similar to versions you can get off the shelf. You are correct about calculations of BL to increase sensitivity. I believe modifcations were done to widen the gap length including more of the VC thus increasing the L not B in the product. Magnet added would need to be inside the closed structure to include the pole piece, not easy for DIY.

8th March 2006, 08:03 PM	#1
elviukai diyAudio Member Join Date: Apr 2003 Location: EU- Electronic Union country	I need to beef 2-3db from 18w9545 hi, I am thinking to add magnet to scan spek 18w9545. it has 88-88.5db I REALLY need at least gain 3% it plays in 8ltr ported box how will change vas,qts and other pr. the box volume is stricly limitation of 7-9ltr thank in advance// __________________ natural sound reproduction from traditional dynamic drivers?!! come on.. no no, it can be.. it must be!..

9th March 2006, 10:18 AM	#2
elviukai diyAudio Member Join Date: Apr 2003 Location: EU- Electronic Union country	anybody? __________________ natural sound reproduction from traditional dynamic drivers?!! come on.. no no, it can be.. it must be!..

9th March 2006, 03:04 PM	#4
elviukai diyAudio Member Join Date: Apr 2003 Location: EU- Electronic Union country	hi thanks for the answer, I want to increase in 3db from 88db/w/m to 90-91db. that would be probably 3% gain in Bl force factor if I am not mistaken. is it posible to achieve 90-91db with extra magnet. as I understand one direction it woulkd be semi shielded and another direction increase BL and thus sensitivity? or I am mistaken? shame to say but I have never played with theese extra magnets and dont know anything and what size and lenght magnet should be, maybe two extra magnets will do better. somehow I pesimistic about gain 3db from 18w9545-02.. it already have 88.5db.w.m and 120mm magnet. and BL is 8.5-9. anyone played with added magnets? __________________ natural sound reproduction from traditional dynamic drivers?!! come on.. no no, it can be.. it must be!..

9th March 2006, 05:05 PM	#6
elviukai diyAudio Member Join Date: Apr 2003 Location: EU- Electronic Union country	there is no mistery -I am doing wilson audio(alreday alsmost done) watt puppy 6 clone. not similar speaker or look like WA system 7 but exact . exact enclosures size and volume, exact weight(last was very hard job, used materials which is very good for damp[ing but not for health) grils, labels . - exact speakers. and 90% close to original series filter, I alreday get the same FR , phase xover points all I need is increase midrange sensitivity 3db. now I use L pad 4db for tweeters and 2.7ohm in series with woofers. to decrease woofers sensitivity is not very good idea. it tooked alsmost year to colect technical info about this speaker and spend lot of money for original dedicated midrange drivers (taken from wilson Benech 10 000eur speakers) the speakers itsel has increribly speed and power,slamm from such a big and weight woofers and especialy midrange. . but sensitivity is 87db. too low to folow originals. so here is all story.. so only way is to beef up 3db from midrange adding 47Ohm resistors in series to tweeter improoves low frequency response!! this one was a joke __________________ natural sound reproduction from traditional dynamic drivers?!! come on.. no no, it can be.. it must be!..

11th March 2006, 06:50 PM	#9
elviukai diyAudio Member Join Date: Apr 2003 Location: EU- Electronic Union country	what is autotransformer? are you suggesting to conect some thing to lower impedance of midrange? __________________ natural sound reproduction from traditional dynamic drivers?!! come on.. no no, it can be.. it must be!..


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9th March 2006, 11:43 AM	#3
sreten diyAudio Member Join Date: Nov 2003 Location: Brighton UK	Hi, Vas, Qms and Fs will not change. You can estimate the change in Qe (and thus Qts) by messing around in WinISDPro, decresing Qe until you get the efficiency you want, or plug in the efficiency you want and let it work out Qe and Qts. I presume you want to gain 3dB not 3%, (or do you want 3% real efficiency ?) /sreten.

11th March 2006, 02:29 PM	#7
sreten diyAudio Member Join Date: Nov 2003 Location: Brighton UK	Hi, well using a autotransformer on the mid is a possibility, but you'd have to scale the crossover component values to suit. The consequence would lower impedance over the midrange, but you should get a similar voltage sensitivity, dB/2.83V. /sreten.

11th March 2006, 02:39 PM	#8
Nemophyle diyAudio Member Join Date: Sep 2004 Location: paris	i'm really interrested into this also ... i have a couple of magnet i could use for testing, but i would need information about how to proceed. I could then do some T/S tests and see how the parameters changes

12th March 2006, 01:17 AM	#10
infinia diyAudio Member Join Date: May 2005 Location: Californication	Wilson audio used OEM drivers similar to versions you can get off the shelf. You are correct about calculations of BL to increase sensitivity. I believe modifcations were done to widen the gap length including more of the VC thus increasing the L not B in the product. Magnet added would need to be inside the closed structure to include the pole piece, not easy for DIY. __________________ like four million tons of hydrogen exploding on the sun like the whisper of the termites building castles in the dust

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