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Looking for a change [message #78520] Mon, 02 December 2013 11:30 Go to next message
BFP is currently offline  BFP
Messages: 48
Registered: May 2009
Baron
Hello Wayne

I have a smallish room 12.5x20x8ft. I have experimented with a few speakers over the years including Newform 645 ribbons and lately a pair of GR research OB7s that I built from a kit. None of these speakers have meant my expectations in this room. I think back to the 70's when I was listening to a cousins systems that had Altec A7's or a pair of large 3 way 12" speakers of some sort.

These speakers seemed to have more body and realism in the lower mid range than I can get from modern speakers. I'm wondering if this is partially due to the narrow width of most modern speakers. A wider speaker like the Pi4 would have a much lower baffle step frequency. I am considering a set of Pi4 and am wondering what sort of bass extension I can expect in a room this size? I have 2 15" subs that I can use to fill in the bottom.

Currently, I have a summed mono setup for a crossover. The sub boxes are sealed and I am using an EQ circuit that funcionally is like the Linkwitz transform but uses circuitry that I came up with myself. The result is great deep bass but it always seems like the lower mids can't keep up. With the OB7's being a dipole in the mids, I need to move them away from the back wall 5 ft for the best imaging. This may also be a factor and I understand that the Pi4 is designed to be used close to the back wall.

I am ready to try something different and looking at the very well documented and researched Pi designs has made me think this may be a good place to start. I would also like to experiment with lower powered amps, tube and SS, and having a set of high efficiency speakers would be great.

Are corner horns a possibility in a room this small? It is a closed rectangular room but does have closet doors on the end wall where the speakers would be placed.

Could you send me a copy of the 4pi plans? I'd like to take a look at the cabinet details.

Thank You

Brian
Re: Looking for a change [message #78524 is a reply to message #78520] Mon, 02 December 2013 15:05 Go to previous messageGo to next message
Wayne Parham is currently online  Wayne Parham
Messages: 18706
Registered: January 2001
Illuminati (33rd Degree)

I've sent the plans. You've got mail!

I would suggest using your existing subs, flanking the mains, as described in these posts:
For more information:
Re: Looking for a change [message #78543 is a reply to message #78520] Wed, 04 December 2013 17:14 Go to previous messageGo to next message
BFP is currently offline  BFP
Messages: 48
Registered: May 2009
Baron
Thank you for the plans. I'll probably order the 290's from you. It may be a while before I get all the parts together to build these. I just missed out on getting a used pair of 2225 woofers that had been in a movie theatre system. The price was good and it would have given me a taste of the JBL sound. The price for new 2226 woofers is pretty steep. If I had to import them into Canada it would be crazy expensive. The Canadian distributer I've found carries Eminence and B and C woofers. When I look at the Omega response curve it has a funny dip in it between 2 and 300 hz as well as a good sized peak before the roll off. This is a pretty demanding application for a 15" woofer. I'm just worried that the Omega will not have the clarity in the mids that I'm looking for. Are there any other alternatives out there that are less pricey than the 2226?
Re: Looking for a change [message #78550 is a reply to message #78543] Thu, 05 December 2013 16:51 Go to previous messageGo to next message
Wayne Parham is currently online  Wayne Parham
Messages: 18706
Registered: January 2001
Illuminati (33rd Degree)

Sorry, no. This design is specifically for the Omega 15 or JBL 2226. The JBL is the premium model, as you know, and is worth the upgrade cost. You might try and find a used pair, but make sure they are in good condition. Factory reconed drivers are an option, but make sure they use original OEM parts.

Re: Looking for a change [message #78552 is a reply to message #78550] Thu, 05 December 2013 18:16 Go to previous messageGo to next message
BFP is currently offline  BFP
Messages: 48
Registered: May 2009
Baron
Wayne is the 2225 an acceptable substitute for 2226. There is someone trying to sell some 4508 boxes locally with what is probably 2225's in them. I thought he had sold them to someone else but apparently the deal fell through. Is there anything that I should specifically check other than VC resistance and the physical condition of the cone/surround. These were in a movie theatre.
Re: Looking for a change [message #78554 is a reply to message #78552] Thu, 05 December 2013 21:59 Go to previous messageGo to next message
HPower is currently offline  HPower
Messages: 16
Registered: October 2013
Location: Newmarket, ON Canada
Chancellor
BFP,

I hear you on the 2226 prices for us Canucks!


PM sent.


The 3 most feared words in racing... "Powered by Honda"
Re: Looking for a change [message #78555 is a reply to message #78520] Thu, 05 December 2013 22:04 Go to previous messageGo to next message
HPower is currently offline  HPower
Messages: 16
Registered: October 2013
Location: Newmarket, ON Canada
Chancellor
Hey Brian,

I just tried to PM you, but it looks like you do not have you PM feature tuned on in your preferences.

I am also sourcing out parts for a 4Pi build and rather than putting out the mega bucks that it takes to get a pair of new 2226s up here I just got a pair via Fleabay.

If you want to email me, I can go into more detail about my adventures.

Tom

tcol@rogers.com


The 3 most feared words in racing... "Powered by Honda"
Re: Looking for a change [message #78559 is a reply to message #78552] Fri, 06 December 2013 10:19 Go to previous messageGo to next message
Wayne Parham is currently online  Wayne Parham
Messages: 18706
Registered: January 2001
Illuminati (33rd Degree)

BFP wrote on Thu, 05 December 2013 18:16
Wayne is the 2225 an acceptable substitute for 2226.

It should work, but it's a combination I haven't measured. The 2225 (and the 2205 before that) were in previous versions of my designs, but those used different tweeters and crossovers. We've moved on since then, using better compression drivers and better horn flares. All these changes were incremental - no huge paradigm shifts - but they were often accompanied by small crossover changes to optimize for the components used. So since the 2225 hasn't been in the design path for a while, all I can say is "it should work" but hasn't been verified.

Re: Looking for a change [message #78560 is a reply to message #78559] Fri, 06 December 2013 10:56 Go to previous message
BFP is currently offline  BFP
Messages: 48
Registered: May 2009
Baron
Thanks Wayne. I figured it would not be optimal. I'm going to keep looking locally for used woofers. I've got most of the xover parts already, including 14g coils.

When the time comes to build I'll make a decision on the 2226 or Eminence.
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