half changin' with the Rola 8MX

aardvarkash10 · 29th May 2010, 03:04 AM

ok, so I have a few of these elderly not-such-great-spec ROLA (Plessey) 8 inch paper cone speakers with whizzer.

I also have 2 factory designs for a slot-vented 1.5 or 2 cubic ft box.

As I understand it, the chang was a similar situation - a design developed from an older slot vent box design.

If I maintain the same box volume, and follow a generic half chang layout am I heading in the right direction, and are there any watchouts on the trip?

I figure I'm only up for around $20 of materials, so an experiment for a wet weekend...

planet10 · 29th May 2010, 06:18 AM

Quote:

Originally Posted by aardvarkash10

As I understand it, the chang was a similar situation - a design developed from an older slot vent box design.

Not really. Scott crossed a Big Vent Reflex with a Fonken and got Calhoun... then he went nuts when it was shown to work really well.

dave

aardvarkash10 · 29th May 2010, 07:23 AM

thanks Dave - I knew you or Scott would be in to straighten out my antipodean thinking...

Nonetheless - am I miles wide of the mark?

Scottmoose · 29th May 2010, 09:17 AM

Without any measurements of the drivers, can't really pass much in the way of comments, other than noting that a lot of trad. BR loads were generalised for maximum efficiency at Fb, & then needed a fair bit of empirical adjustment to dial in. You might give them a shot in the Chang cabinet itself; Vb isn't too far off the 1.5ft^3 box you say you have plans for, so it'll probably work as well in that as anything based on the available information.

aardvarkash10 · 29th May 2010, 10:04 AM

thanks guys - can't ask for a lot more than that given the guesswork nature of the request!

kyoshisama · 4th December 2011, 06:40 AM

gday mate do you still have the old rola 8 inch speakers ???? i have an old valve amp and it was runnign an 8 inch rola speaker in it anthe idiot i bought it off threw the speaker away

(((
Geoff

29th May 2010, 03:04 AM	#1
aardvarkash10 diyAudio Member Join Date: Mar 2007 Location: Auckland, NZ	half changin' with the Rola 8MX ok, so I have a few of these elderly not-such-great-spec ROLA (Plessey) 8 inch paper cone speakers with whizzer. I also have 2 factory designs for a slot-vented 1.5 or 2 cubic ft box. As I understand it, the chang was a similar situation - a design developed from an older slot vent box design. If I maintain the same box volume, and follow a generic half chang layout am I heading in the right direction, and are there any watchouts on the trip? I figure I'm only up for around $20 of materials, so an experiment for a wet weekend... __________________ Yes, conservatism thrives on low intelligence and poor information. But the liberals in politics... continue to back off, yielding to the supremacy of the stupid. It's turkeys all the way down. - George Monbiot, guardian.co.uk, 6 Feb 2012

29th May 2010, 07:23 AM	#3
aardvarkash10 diyAudio Member Join Date: Mar 2007 Location: Auckland, NZ	thanks Dave - I knew you or Scott would be in to straighten out my antipodean thinking... Nonetheless - am I miles wide of the mark? __________________ Yes, conservatism thrives on low intelligence and poor information. But the liberals in politics... continue to back off, yielding to the supremacy of the stupid. It's turkeys all the way down. - George Monbiot, guardian.co.uk, 6 Feb 2012

29th May 2010, 10:04 AM	#5
aardvarkash10 diyAudio Member Join Date: Mar 2007 Location: Auckland, NZ	thanks guys - can't ask for a lot more than that given the guesswork nature of the request! __________________ Yes, conservatism thrives on low intelligence and poor information. But the liberals in politics... continue to back off, yielding to the supremacy of the stupid. It's turkeys all the way down. - George Monbiot, guardian.co.uk, 6 Feb 2012

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29th May 2010, 09:17 AM	#4
Scottmoose diyAudio Member Join Date: Mar 2005 Location: UK	Without any measurements of the drivers, can't really pass much in the way of comments, other than noting that a lot of trad. BR loads were generalised for maximum efficiency at Fb, & then needed a fair bit of empirical adjustment to dial in. You might give them a shot in the Chang cabinet itself; Vb isn't too far off the 1.5ft^3 box you say you have plans for, so it'll probably work as well in that as anything based on the available information.

4th December 2011, 06:40 AM	#6
kyoshisama diyAudio Member Join Date: Dec 2011	gday mate do you still have the old rola 8 inch speakers ???? i have an old valve amp and it was runnign an 8 inch rola speaker in it anthe idiot i bought it off threw the speaker away ((( Geoff

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