Re: Mystery Cabinets
Olsen's speakers date from the early 50s (maybe even late 40s), and a BC would be a likely place to find some.
dave
mrfeedback said:
Olsen's speakers date from the early 50s (maybe even late 40s), and a BC would be a likely place to find some.
An externally hosted image should be here but it was not working when we last tested it.
dave
Hello all...
Just got back from the UP and am happy to see the thread continuing.
This "big box" configuration is about the only type of box I've never played with and my life will not be complete without building them.
Mrfeedback, that is a very interesting comment about those boxes being very relaxed and free sounding. This is similar to other comments I have heard regarding infinite baffling, that the bass extension is very clean and unforced, i.e., no peakiness or strain as long as you stay within the limits of these older drivers.
They were designed to be powered by relatively low powered tube amps and will probably never match a high powered ported design for that "blow out the candle" punch.
I am not convinced, truthfully, that a box that heavy and rigid is necessary at lower listening levels. If the box is airtight and rattle free and big enough, I wonder if one would hear any effects from the boxes.
I'll probably build them a little lighter and beef them up later if necessary. I'll probably also put casters on them for portability.
Thanks again for all your input, glad to see there is some interest in vintage drivers...
Lee
Just got back from the UP and am happy to see the thread continuing.
This "big box" configuration is about the only type of box I've never played with and my life will not be complete without building them.
Mrfeedback, that is a very interesting comment about those boxes being very relaxed and free sounding. This is similar to other comments I have heard regarding infinite baffling, that the bass extension is very clean and unforced, i.e., no peakiness or strain as long as you stay within the limits of these older drivers.
They were designed to be powered by relatively low powered tube amps and will probably never match a high powered ported design for that "blow out the candle" punch.
I am not convinced, truthfully, that a box that heavy and rigid is necessary at lower listening levels. If the box is airtight and rattle free and big enough, I wonder if one would hear any effects from the boxes.
I'll probably build them a little lighter and beef them up later if necessary. I'll probably also put casters on them for portability.
Thanks again for all your input, glad to see there is some interest in vintage drivers...
Lee
Memories.....
Dave , thanks for going to the trouble in posting the pic.
I sort of remember the protrusions being more flat topped and hemispherical/conical (like the bottom of an egg carton) and a little further out towards the edge of the cone.
Also vaguely remember that they were Rola or some British firm maybe.
The cabinet material was maybe 16mm or so panelling.
This is 20+ years ago, and it was the morning after a big night of barbeque, campfires, live bands, boozing and camping out in a bush valley setting.
I still remember the sound of these the next morning though.
Eric.
Dave , thanks for going to the trouble in posting the pic.
I sort of remember the protrusions being more flat topped and hemispherical/conical (like the bottom of an egg carton) and a little further out towards the edge of the cone.
Also vaguely remember that they were Rola or some British firm maybe.
The cabinet material was maybe 16mm or so panelling.
This is 20+ years ago, and it was the morning after a big night of barbeque, campfires, live bands, boozing and camping out in a bush valley setting.
I still remember the sound of these the next morning though.
Eric.
Hi Lee, My friend who owns the heavy Lansing loaded cabinets, built these as a project whilst doing his EE degree 25 years ago - maybe more.
He told me that he had the particleboard panels custom pressed and were double pressured or something.
They were 2" thick and REALLY solid.
This is going quite extreme, but it works.
Cabinets of speakers like Duntech Sovereigns and the bass cabinets of Gensis 1 system are REALLY solid too.
For sealed cabinets this is required IMO within realistic considerations of course.
For open backed cabinets this can be much relaxed I expect.
An easy experiment just to mind is to go to the recycling center, buy two old doors for $10.00, cut suitable holes, mount the drivers and stand them up, and see what you get.
The rear going panels (that make it an open backed box) could be resonably light perhaps, or even a totally dead material like sheets of carpet, to give a degree of loading on the rear wave.
Just some musings.
Eric.
He told me that he had the particleboard panels custom pressed and were double pressured or something.
They were 2" thick and REALLY solid.
This is going quite extreme, but it works.
Cabinets of speakers like Duntech Sovereigns and the bass cabinets of Gensis 1 system are REALLY solid too.
For sealed cabinets this is required IMO within realistic considerations of course.
For open backed cabinets this can be much relaxed I expect.
An easy experiment just to mind is to go to the recycling center, buy two old doors for $10.00, cut suitable holes, mount the drivers and stand them up, and see what you get.
The rear going panels (that make it an open backed box) could be resonably light perhaps, or even a totally dead material like sheets of carpet, to give a degree of loading on the rear wave.
Just some musings.
Eric.
Altec 605A's
Gentlemen:
Please excuse me if this is not an appropriate time or place for my observation and question, but...
I, too, have some similar vintage gear (Altec 605 A's in perfect condition) and have started to design a closed box speaker using these 15 inch, coaxials.
The specs for this driver combo is Vas=14.33 cuft, Qts=0.25, Fs=30.30 and, I think that I choose the Qtc (0.7 for flat response). Using Alpha=[(Qtc/Qts) squared] - 1 which yields Alpha = 6.84.
With Vb=Vas/Alpha=14.33 cuft/6.84=2.045 cuft for closed box. This seems very small compared with the sizes referenced in this discussion. Also, a web search of reviews for the Altec 605A showed one written by Tom Brennan where his speaker boxes were about 7 cuft vented. I thought venting would make the boxes smaller compared to closed.
I must be mistaken in my understanding and/or calculations. Please set me straight while you all are on the topic.
Your input greatly appreciated!
Rick
Gentlemen:
Please excuse me if this is not an appropriate time or place for my observation and question, but...
I, too, have some similar vintage gear (Altec 605 A's in perfect condition) and have started to design a closed box speaker using these 15 inch, coaxials.
The specs for this driver combo is Vas=14.33 cuft, Qts=0.25, Fs=30.30 and, I think that I choose the Qtc (0.7 for flat response). Using Alpha=[(Qtc/Qts) squared] - 1 which yields Alpha = 6.84.
With Vb=Vas/Alpha=14.33 cuft/6.84=2.045 cuft for closed box. This seems very small compared with the sizes referenced in this discussion. Also, a web search of reviews for the Altec 605A showed one written by Tom Brennan where his speaker boxes were about 7 cuft vented. I thought venting would make the boxes smaller compared to closed.
I must be mistaken in my understanding and/or calculations. Please set me straight while you all are on the topic.
Your input greatly appreciated!
Rick
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