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Unfaithfull to Kef
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Lee in Montreal
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Joined: 22 Aug 2009
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PostPosted: Tue Sep 21, 2010 9:21 pm    Post subject: Unfaithfull to Kef Reply with quote

Yup. I bought some vintage JBL Pro components and started playing with that.

I purchased a 2235h 15" woofer and built a 6.9cf (195L) bass reflex enclosure. The 2235h is the famous audiophile pro driver found in high end studio monitors such as the 4330 and 4335. These are not powerfull drivers as they are intended to go deep (Fs is 20Hz) and reproduce music accurately.

I am driving the woofer as we speak as a subwoofer. Damn it sounds good. I made two ports. One tuned to 20Hz (the driver's Fs) and one to 26Hz (the cabinet's resonance. I am testing by blocking the port. I fell in love with the vintage JBL Pro stuff. A very different world from Kef's. Wink

Will post pictures soon.
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Kef Calinda - since 1979
Kef Cantata - since 2009
Kef 105/2 - since 2009
Evo 105/2 - in the build
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speakerguru
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Location: Green Hut, Tovil

PostPosted: Thu Sep 23, 2010 10:02 am    Post subject: Re: Unfaithfull to Kef Reply with quote

Lee in Montreal wrote:
I made two ports. One tuned to 20Hz (the driver's Fs) and one to 26Hz (the cabinet's resonance. I am testing by blocking the port.

Shocked does each port see a separate volume? Otherwise you are just putting two acoustic masses in parallel, resulting in one resonance at a frequency set by the volume and the equivalent mass of the ports in parallel.
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Lee in Montreal
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PostPosted: Thu Sep 23, 2010 4:09 pm    Post subject: Re: Unfaithfull to Kef Reply with quote

speakerguru wrote:
does each port see a separate volume? Otherwise you are just putting two acoustic masses in parallel, resulting in one resonance at a frequency set by the volume and the equivalent mass of the ports in parallel.


I am using one or the other. Not both at the same time.
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Kef Calinda - since 1979
Kef Cantata - since 2009
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speakerguru
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PostPosted: Fri Sep 24, 2010 6:50 am    Post subject: Reply with quote

Idea ah-ha. Understood now.
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Lee in Montreal
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PostPosted: Wed Sep 29, 2010 6:25 pm    Post subject: Reply with quote

Here's what I just built.
195L enclosure with 15" JBL 2335h w/ Fs 20Hz






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proffski
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PostPosted: Thu Sep 30, 2010 11:06 am    Post subject: Reply with quote

Only one subwoofer? Tut tut! Wink

I'll bet that it makes the trousers flap when you play a good recording of something like the Saint-SaŽns's 'Organ Symphony'! Shocked
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Lee in Montreal
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PostPosted: Thu Sep 30, 2010 1:25 pm    Post subject: Reply with quote

Indeed only one as it is a test. 190L is big and I wanted to make sure I could do something that is easy to integrate. It is heavy, yet easy to move around. Soundwise, I am happy. Currently looky for a Yamaha PC2002M to drive that sub.
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proffski
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PostPosted: Thu Sep 30, 2010 8:17 pm    Post subject: Reply with quote

Impressive, what kind of music have you been trying it with?

http://www.jblpro.com/pages/components/2235h.htm
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Lee in Montreal
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PostPosted: Thu Sep 30, 2010 10:05 pm    Post subject: Reply with quote

I played all sort of stuff, fed by an ADCOM 5500 (yurk) and a Quad 606 (much better) and looking for a Yamaha PC2002M for that improved bass control.



I just sold four B300 to finance the purchase of the "new" amp. But things are going to be tough as I also just found a Quad 520f for dirt cheap, locally. Arghhhh...


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proffski
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PostPosted: Thu Sep 30, 2010 10:47 pm    Post subject: Reply with quote

Mm, I love the sound of BIG amplifiers, somehow more contol and ooh the bass...
I've had a couple of Amcrons (DC150 & DC300) and Krell SA100, it just loved to play with the KEF Model Four Reference series.
Somehow even when pushed the system never sounded too loud, that is until you tried to speak and then you reralised that the bass was modulating the air in your lungs, a bizzare feeling! Shocked

I think that they are now living happily in retirement somewhere in Scotland.
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Lee in Montreal
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PostPosted: Fri Oct 15, 2010 7:58 pm    Post subject: Reply with quote

Look what followed me home.



Yup. A pair of JBL 4530 (copies) with 2225h drivers, that I purchased to study, until I make my own with nice wood and finish. The 4530 cabinet is know for its great kick, while my other sub with 2235h will complement them with deep bass.
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Kef 105/2 - since 2009
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proffski
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PostPosted: Fri Oct 15, 2010 8:21 pm    Post subject: Reply with quote

Eek! You will be contravening some international arms treaties with these behemoths! Smile
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I contend that for a nation to try to tax itself into prosperity is like a
man standing in a bucket and trying to lift himself up by the handle.
-Winston Churchill
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Lee in Montreal
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PostPosted: Wed Oct 20, 2010 10:38 pm    Post subject: Reply with quote

proffski wrote:
Eek! You will be contravening some international arms treaties with these behemoths! Smile


The energy coming from these 4530 is incredible. Under 150Hz, the sound (shock wave?) comes from the large throat, acoustically amplified by the expansion rate of that "labyrinth". Above 150Hz, the sound comes directly from the driver. The kick coming from the cabinet literally shakes your pants. Playing at reasonable level literally makes the whole house shake. Everything resonates while the sound is still smooth on the ears.

But hey, as an ex DJ from the early 1980s, I had to have a pair of JBL 4530.

If I could, I'd like to have a set of 4520s, but then I need to live in celibacy.


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proffski
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PostPosted: Wed Oct 20, 2010 11:11 pm    Post subject: Reply with quote

One word.... AWESOME!!!
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I contend that for a nation to try to tax itself into prosperity is like a
man standing in a bucket and trying to lift himself up by the handle.
-Winston Churchill
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Lee in Montreal
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Joined: 22 Aug 2009
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PostPosted: Thu Oct 21, 2010 4:31 am    Post subject: Reply with quote

proffski wrote:
One word.... AWESOME!!!


Yup. The 4520s are awesomely gorgious. If you have the room. Imagine four woofers pressuring the air. And what's great is that the plans are available from the net. Therefore, they are easy to get if you want to build some.

BTW I just purchased a 240wpc pro Yamaha P2200 to power my 4530s... 50 lbs of amplifier. These things are built like a tank. Mine is a 1978 unit.

JBL 4520 - sub bass - two woofers


JBL 4530
- kick bass - one woofer

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Kef Calinda - since 1979
Kef Cantata - since 2009
Kef 105/2 - since 2009
Evo 105/2 - in the build
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