Goodmans ARU Unit - Do they work?

[altecman]

In a earlier post I was talking about how my large vintage Goodmans 3 way speakers have a ARU (model 172) fitted and wondered if anyone has had experience with these devices.
It's seems that some are saying that these units were basically designed before T&S parameters became available and tube gear was common.
As I've moved all my tube gear on (due to high maintenance issues not sound) I find that the high damping factor of modern SS amps might be the reason why ARU units don't produce bass as they were advertised to.
I have always had success with ported boxes and wonder if anyone has changed their ARU equipped Goodmans to a more conventional ported design.

I've roughly calculated that my boxes are 12 ft3 (330 litres) and will tune them to 35 hz. I'm going to removed the ARU unit and blank the hole with a panel fitted with 2 X 109mm ports, 63mm in length. This way the box hasn't been alterated so that I can revert back in case this doesn't work.

 

[kbott]

my situation was a little different than yours I had a pair of goodmans sherwood cabinets that I bought without ARU's. when i added them it was like a night and day difference to the better. whatever you do dont get rid of them or alter the cabs as your resale value will just be parts

 

[altecman]

Thanks for the advise. There doesn't seem to be much resale value for Goodmans gear unless there are Axiom 80's, it's a pity as they seem to be well made. I just have to try something different as there's no bass and when you have twin 12" in a 330 litre box it's a little disheartening.

 

[kbott]

those4 aru's will go for $200/pair on eBay without any problem don't know what yours are loaded with but ny pair of sherwoods with audiom 50, midax trebax crossover and aru's sold for $1350 before the holidays people typically part them out but complete cabinets are pretty rare and will command decent money

 

[altecman]

The driver complement for each box is: Audiom 51 x 2, Midax 400, Trebax 100 x 2 (only one fitted at present), XO/950/5000 xover, variable step attentuator x 2 & ARU 172. The cabinets aren't factory made Goodmans but by a cabinet maker circa early 60's, as the craftmanship appears to be beyond most home builders. In one of my earlier post there are photos with the original cloth and doors fitted, since then I've removed the silk cloth as it wasn't acoustically transparent.

 

[kbott]

while I have seen one knockdown kit manufactured by goodmans on ebay in the last few years most goodmans of that era were made according to goodmans plans that one bought and then loaded with components I've never seen one with a vertical mid but then again I never bought a booklet with the plans they're about 15-20 pages and pop up on ebay occasionally

i can't help you with the bass issue mine had very satisfying low end thump i sort of regret selling them as my wife really liked the look. Oh well things change but you do have something unique and valuable I think you're partly expecting something to sound not like it was intended

 

[seanrr]

I know this is an old thread, but I could not resist resurrecting it since I am trying to build an ARU cabinet. I thought this old article I dug up from EJ Jordan, who created the ARU for Goodmans, was appropriate to this thread. In the article, most of which is way over my head, he looks at the "Theil Small" parameters with skepticism...

http://www.ejjordan.co.uk/PDFs/parameter_game.pdf