Jensen P8R �n Karlsen 12

RE: Jensen P8R ìn Karlsen 12, posted on September 22, 2021 at 12:00:24
grindstone Audiophile Posts: 188 Location: GMT -6 Joined: August 10, 2008	FWIW -- Guessing that, as a group, we're not ignoring your post (and it's not dead here). Suspect we're all waiting for the resident Karlson-guy to show-up with your answer.

RE: Jensen P8R ìn Karlsen 12, posted on September 22, 2021 at 12:43:36
wclarson12 Audiophile Posts: 30 Location: Hudson Valley NY Joined: April 10, 2014	Well thanks. I'm very fond of this particular driver. Perhaps even 2 in the 15 inch Karlson

RE: Jensen P8R ìn Karlsen 12, posted on September 22, 2021 at 12:54:51
Bill Fitzmaurice Industry Professional Posts: 5371 Location: New England Joined: October 20, 2002	Loaded in a Karlson or any other box I don't see this musical instrument driver being much good for anything other than musical instruments, specifically electric guitar.

RE: Jensen P8R ìn Karlsen 12, posted on September 22, 2021 at 15:22:36

FRG7SWL
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Posts: 2109
Location: NorCali
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Wclarson12, have utilized Mesa/Jensen P10RI drivers in a pair of inherited ESS Model 10 cabs for over 15 years. Along with form-fitting Motorola piezo tweeters with Dayton 5.6 uF polyprop crossover caps & 16-gauge wiring. Stock 4-ohm woofs were nondescript, & stock Philips tweets were screechy. Now that pup sounds auld-skool magical, as befits its' Bradshaw Road roots. P8R's are described as being slightly cleaner sounding than ceramic C8R brethren, with that classique warm Jensen "harmonic bloom" tone. 8 ohm drivers have 92.5 dB sensitivity, & are rated for 25 watts. Speaker re-coner Ron Neil said Jensen alnicos were originally used for radio audio (as was Celestion's classique Blue alnico), but made harmonic history combined with Fender instrument amps. Enjoy! 73s para Sactown

Altec Lansing 421A, posted on September 22, 2021 at 16:30:48
Alpha Al Industry Professional Posts: 2958 Location: N. Carolina Joined: February 16, 2004 Contributor Since: December 3, 2015	The 15" woofer that was used in many Voice of the Theater systems was classified as a musical instrument speaker as well, but found other uses.

RE: Jensen P8R Ã¬n Karlsen 12, posted on September 22, 2021 at 18:11:25
Coner Audiophile Posts: 3703 Location: S.W. Washington state, USA Joined: November 17, 2001	I'd be surprise if Eminence didn't have one as good or better.

RE: Altec Lansing 421A, posted on September 23, 2021 at 05:06:01
Bill Fitzmaurice Industry Professional Posts: 5371 Location: New England Joined: October 20, 2002	Altec never made a driver for electric guitar. Drivers used in VOT, like the 418-8H, were often used for electric bass, but the specs for electric bass and electric guitar are totally different. The Jensen P8R is an electric guitar driver.

RE: Altec Lansing 421A, posted on September 23, 2021 at 07:09:55

Alpha Al
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Posts: 2958
Location: N. Carolina
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Contributor
Since: December 3, 2015

Altec Musical Instrument Speakers. It's my understanding that the 421A was designed specifically for bass guitar, but it was also used in a lot of Voice of the Theater boxes that were sold through music stores (not pro sound contractors).

http://greatplainsaudio.com/wp-content/uploads/2016/06/400-S

RE: Altec Lansing 421A, posted on September 23, 2021 at 07:28:33

Bill Fitzmaurice
Industry Professional

Posts: 5371
Location: New England
Joined: October 20, 2002

I'm well aware of the 421A, I bought one in 1970. It was not an electric guitar speaker. The Jensen P8R that's the subject here is. That's why it's been used by Fender since the 1960s. Don't believe me, read the description from Jensen.

https://www.jensentone.com/vintage-alnico/p8r

RE: Altec Lansing 417-8H, posted on September 23, 2021 at 08:29:27

FRG7SWL
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Posts: 2109
Location: NorCali
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Bill Fitzmaurice, Carlos Santana rocked Altec 417-8H speakers in his mid-70s Mesa Mark I amps. That tone is prominent on "Welcome" & "Borboletta" studio albums, as well as "Lotus" live album. Saw one up close-n-personal, courtesy late A Brown Soun owner John Harrison. Whilst picking up some hemp-reconed speakers, natch. John wondered if he could get $1,500 for it. Told him he could get that amount for moi's Mesa Mark I re-issue & hemp-reconed 2 x 12 Recto Cab, which moi would gladly trade for. Mr. Harrison politely refused. BTW, also heard Randy Rhodes preferred 817-8H speakers too! 73s para Sactown

RE: Altec Lansing 417-8H, posted on September 23, 2021 at 09:01:49
Bill Fitzmaurice Industry Professional Posts: 5371 Location: New England Joined: October 20, 2002	I used 417-8H as well, in my bass cabs and in the JBL4560 inspired horn loaded PA cabs I designed and built in 1969. With their long xmax the 417s didn't have the compressed sweetness that Greenbacks did even when driven by a 22 watt Fender Princeton that Randy Smith hadn't pooged. The Altecs could get a good compressed tone, but it was sourced by the amp and effects pedals, not the speaker.

RE: Altec Lansing 417-8H, posted on September 23, 2021 at 11:01:31
Alpha Al Industry Professional Posts: 2958 Location: N. Carolina Joined: February 16, 2004 Contributor Since: December 3, 2015	I'm a guitar player, and have played through 417's as well. They have a nice bright and clear tone, similar to a JBL D120.

RE: Jensen P8R ìn Karlsen 12, posted on September 23, 2021 at 14:31:14

Retsel
Audiophile

Posts: 1239
Joined: April 17, 2000

I just looked up the Q for those drivers, and it is very high - well over 1. Those drivers would work well mounted in an open baffle, but to come close to working for a Karlson, the box would have to be really big, which would be a waste of wood.

Drivers that work well in a Karlson have a much lower Q - at leas under 0.6. For the full sized Karlson, drivers with a Q of around 0.3 work really well. I use EVM-15L speakers which are also musical instrument speakers, but with a Q normally under 3, and they work really well in a K15.

Retsel

RE: Jensen P8R Ã¬n Karlsen 12, posted on September 23, 2021 at 17:53:52
wclarson12 Audiophile Posts: 30 Location: Hudson Valley NY Joined: April 10, 2014	Okay, thanks. I won't pursue that idea

RE: Altec Lansing 417-8H, posted on September 23, 2021 at 19:03:05
claudej1@aol.com Audiophile Posts: 817 Location: Detroit Joined: August 17, 2007	IN 1974, I used an Altec 421-8H in 20 cubic foot boxed, tuned by ear. Recently did a Simulation and I had a 40 Hz. peak before reflex rolloff. So I was right to do what I did. However modern tools would have had me build a small box. Mine were to minimize scrap from the plywood. 2 x 2.5 x 4 feet. Used the Badmeiff and Davis book's nomogram to start.

RE: Altec Lansing 417-8H, posted on September 24, 2021 at 05:02:30
Bill Fitzmaurice Industry Professional Posts: 5371 Location: New England Joined: October 20, 2002	It's maximally flat in 3 cu ft with a 32Hz Fb, but f3 is only 80Hz. That's not unusual for drivers of that vintage. The D130 was no better. 6 cu ft with a 40Hz Fb works reasonably well. 20 cu ft is nasty, but that was pre-Thiele-Small, where everything was hit or miss seat of the pants.

RE: Altec Lansing 417-8H, posted on September 28, 2021 at 08:13:41

claudej1@aol.com
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Posts: 817
Location: Detroit
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I agree with your comments. I was just a teen ager then. The Badmeiff/Davis book on loudspeakers had a nomogram (Jensen?) and that is how I got started building my third pair of speakers (which I made money with playing college dances with pre recorded music on my Crown Reel to Reel).

I remember spending about $1,000 on Altec and EV components for them, along with a 511B horn, 808 8a driver, etc. That was a LOT of money for a kid back then. Yes the box was bigger than it needed to be but they did sound very good. My next pair of speakers were Klipshorns, which I used to justify my first bank loan for them!

I'm not sure when Tecron TEF came along but I do recall something like a $20,000 price tag!

Now most speaker design software today is cheap or FREE to run on a laptop.

What a world!!!

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Jensen P8R �n Karlsen 12

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