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Good day everybody stuck at home during this self quarrantene. I am sure this is an exhausting question, but I'm looking for Spec's of the 2205B woofer. If someone has 'Test Data' I could surely use as my gear is out of reach at the moment. I'd like to build an enclosre maybe the Onken enclosure, but no spec's. Reaching out to the membership... HELP?
Thanks.. in advance, Francis
I answered in another post? This was the answer:
You could find some useful data here:
http://www.jblproservice.com/pdf/Thi...Parameters.pdf
But the 2205B ? isnt listed there. But look at the 2215A and B you could find some hint whats differ the two from each other i.e. between an A and B (only LE and RE I guess)
Whats your DCR for the 2205B?
2205B is the 16 ohm version of the 2205A. Other than the VC DCR/impedance I believe all of the other parameters should be the same.
Widget
Hi Flodstroem, I also did not find my driver in this list... It is in the archive as a 16 Ohm 15" woofer.. the same as I have. Re. (if I remember correctly) is measured at 13.8 Ohms and the other as 14.3 Ohms.
http://www.lansingheritage.org/image...2205/page2.jpg
Was hoping someone had test gear and could share the spec's... Here's to hope! :cheers:
Francis
Hi Francis,
The info given to you by Flod and Widget is correct, as well as the one you found with regards to 2205. I can't offer you actual test gear measurements, anyway your sample may give little different data than another...
The attached printout is possibly the oldest set of 2205 TS parameters you will likely encounter, and it comes from JBL. It was given to me in 1980 by JBL's distributor in Canada (Gould Marketing) when I purchased the 2205H's (8 ohm). Btw the DC resistance tolerance for the 8 ohm version is 5.1-6.1 ohm (I have somewhere in my previous laptop a JBL document giving those DCR tolerance numbers. Any for 16 ohm? Need to see).
Forget about the box design shown on my printout (posted here for the TS not for box parameters). That cab (5.5 cu.ft./Fb 45 hz) is too large for higher output LF. I didn't use that to house the 2205 since it gave a drooping LF response. There was a response curve printed at the bottom of the printout, but I didn't keep this part.
In the old days, JBL distributors had a larger "pocket size" mini computer with printer to model boxes and the results were printed on thermal paper. Well, data printed on thermal paper disappears after a while... however lucky me had made a back-up photocopy of that printout, which is what I'm posting.
Since the 2205B is old I would use the numbers on the printout, even though they're pretty much the same as those in JBL's TS table (Xmax is a bit more generous on mine). I suggest using about 4 cu.ft./Fb 45-50 HZ enclosure for increased LF output. Don't expect high level deep bass from the driver, it was not designed for this purpose.
P.S. The 1991 fax on thermal paper sent to me by JBL distributor/dealer re 2214H TS parameters is now pretty pale, fading away too, even though its kept in a transparent plastic sleeve... Regards,
Richard
Attachment 86334
Thanks you so much! RMC, Mr Widget and Flodstroem you guys are the "BEST!":applaud:
You have made it possible to work out a design for my enclosure!
Francis
I'd expect that BL should also differ.Quote:
Originally Posted by Mr. Widget
Best regards!
Agreed. Also the Le would increase.Quote:
Originally Posted by Kay Pirinha
Look at the T/S parameters for the later speakers that are offered in two impediences (e.g., H and J), and in almost all cases, the BL and Le are higher for the higher impedience version.
Hi kay,
RE "I'd expect that BL should also differ." Yes, but...
Eargle discusses, in his Loudspeaker Handbook p. 34, the issue of driver impedance adjustment and the related (Bl)^^2/Re ratio, when moving from 8 ohm to 16 ohm driver.
"... the total length of wire in the voice coil will now be 1.4 times ... The new Re will be twice what it was ... and the new value of Bl will be 1.4 times greater. However, (Bl)^^2 will increase by a factor of 2, so we have kept the same ratio as before." (i.e. the Bl squared divided by Re ratio)
Detailed explanation shortened by me since I'm not a good typist... Regards,
Richard
Double impedance needs sqrt 2 times the turns number. Hence sqrt 2 times the BL. In short words ;).
Best regards!
I dont agree to that statement.Quote:
Originally Posted by Kay Pirinha
If for example looking at the JBL TS specs for the 2215A and B, 8 and 16 ohms BL is the same for both models. And thats logic. A 16 ohms speaker sees only half of the current than what the 8 ohms version sees. But voltage increase for the 16 ohms. Both handles the same power hence the same BL factor because there is a relationship between the input power in a given magnetic field and BL factor. My two cents........... :blink:
Quote:
Originally Posted by Flodstroem
The exception to the rule, which is why I noted "most."
http://www.jblproservice.com/pdf/Thi...Parameters.pdf
Hi Flodstroem,Quote:
Originally Posted by Flodstroem
with due respect, no.
1st: If we drive two almost identical loudspeakers that only differ in their impedances (8 vs. 16 ohms) with the same electrical power, the 16 ohms version doesn't draw half the current, but 1/sqrt2 times instead. The required voltage for the same power will be sqrt2 times as high.
2nd: The BL parameter doesn't have anything to do with the voice coil current. Instead, it is the product of the magnetic flux B in the gap and the voice coil wire length L, hence defined by the driver design. To cope with 1/sqrt2 times the VC current, the 16 ohms driver will have sqrt 2 times the VC winding turns compared with the 8 ohms one, and the wire cross section is 1/sqrt2.
Best regards!