Discussion in 'Members' Systems' started by Doc Zinger, Feb 23, 2011.
Great system Doc, and nice narrative on the history of your system.
Would like a little help here with a possible redesign of my sub bass units.
I have been playing around with some of the speaker design software- winISD and plugged in the info/specs on the JBL 2225h drivers in my sub speakers to see what popped out.
The volumne spec came out alot different than the boxes I built, way smaller! I built these about 30 years ago, and don't remember how I came up with the box dimensions, maybe from some Speakerlab info from that era.
JBL 2225h specs; Ots= 0.28, Qms= 2.50, Qes= 0.31, Vas- 169.9 l, FS= 40.0,Xmax 0.20 in, (specs for the 2225h were listed in the program data base) and I now have JBL full spec from their site.
I plugged in the called for values for the program and got a vol of 3107.1 cubic inches( 1.798 cubic ft) in a ported box with 4" rd vent 2.57" long and optim..ID dimensions of 14.79" x 23.67"x 8.88".
The existing as built dimensions/vol are ID 16.5" x 26"x 18" with vol of 7,722 cubic inches(4.47 cubic ft) with a 4" rd vent 12" long.
There is quite a bit of difference here, seems like the calculated optimal dimensions with one at 8.88 inches give shape I haven't seen to often.
Guess I'm asking for someone who knows their calcs to point me in the right direction so I can determine if any changes would make an improvement to the speakers. I do have an Audio Control Richter Scale for the sub it has a built in 1/2 band 6step EQ, which I haven't set up. Could it be used to compensate for the box size.
I'm at the point I've got this itch to build something, rather than build some new speakers maybe I'll just rebuild and improve what I've got if it makes sense.
I'm planning on getting rid of the 6' cabinet between the main speakers and build an open frame 3 bay unit 5' long. And move all the amps off the speakers and into this stand and also go with shorter interconnects. Also think by moving the speakers a foot or so closer together will improve imaging if you go by the rule of 1/3rds= a third from both walls, a third between.(19' long wall). And rotate the subs 90degrees to move the driver center up. any ideas on all this are welcome.
Wow, that is a nice setup. Modest not...pride yes
If you consider that "modest" i'm glad I don't live within 100 miles of you. I don't think my ears could take it if you went to an "over the top" setup
Killer speakers. Dig it!
wow! that looks incredible. is that a NAD turntable? ive never seen one. looks like youve been at this for quite a while and know what you like. thats really what its all about right? have you thought about moving your speakers out into the room a little bit? i am not sure how big the room is, but you may enjoy the results.
thanks for sharing!
Finally was able to buy a pile of oak and get started on the new open style equipment rack to replace the 4 door unit.
A few pics of the start, hope to get most of it done this week, have alot more done than pics show but haven't snapped any new pictures yet.
Was hoping someone would give me a reply to my speaker question on post #23, I'm sure it's just because the right person hasn't seen it yet.
Great gear. Did you try posting your question in the DIY or Speaker forum?
edit: Nevermind, just noticed the original date of this thread.
A few more pics of new oak stand, will be a three bay open unit. The side bays will hold the HK 22 amp stacks on the bottom and the Parasound amp above on shelf. Will have floater shelves set on sorbane disks for the HK amps, the Parasound amps have build in vibration pads.
Will set the active crossovers in middle bay up high and the tuner/cass deck below. Turntable, preamp, and CD player will stay on top.
Very nice work! I like your style.:yes:
Finally got the new equipment rack finished and started the transfer. It was a chance to clean up and get rid of some clutter in the listening room.
Still need to rework the main speakers, new edges and a general clean up and a rework of the subs, am going to mod the porting by add second port and shorting length. Pics of new rack vs old set up.
Got my system rework done today except for some work on the sub units. Alot more work than I first thought, you make one small change and end up having to redo some other thing. Got the mains about 16" closer together which was done for better imaging, so far sounds like it has improved.
Also wanted to get the amps off of the speakers to eliminate possible vibe feedback, also put some Sorbothane pucks/discs under big amp stacks, turntable block and CD player, and a general clean up of hook ups/cables.
Looking to increase port size either by doubling or bigger port, need to research it some more. After this is done will push everything back to wall. A, couple of pics, I think it looks alot cleaner, more modern.
Like your 15" JBL sub. Very nice. It would compliment my Altec model 15's for our 2 channel HT system. What driver is it?
Thanks, 2225's going to recone into 2235's soon if I can ever get them out of the cabinets, they're surfaced mounted and have been undistrubed for about 25 yrs and seem to be stuck to the baffle. Trying not to screw then up so far, but getting alittle PO'd about the whole thing.
If the subs fit the bill as is and you are satisfied with them then there is no reason to mod them.
I too don't like a single sub which is why for my main system I have two (one under each main speaker) connected in stereo.
After a lot of thinking I've decided to try to sell the back end of this system- the 6 amps, 2 active crossovers, the 2 main speakers, the sub bass units, and all cables hooking everything up.
I will keep the front end- pre amp( WTF how could I give up my Classe DR5.) the turntable, CD player, and tuner. I plan to reconfigure a new combo using the Dynavox speakers I built a couple years ago and use a 18" Dayton driver in the cabinet I need to build, it's going to be one heavy SOB, but you need a lot of mass to control a driver this large IMHO.
I will start to clean everything up and maybe make some cloth speaker screens, will try to get some Klipshorn style black cloth is possible.
As heavy as these guys are (1000#+) this will be local endeavor most likely.
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