I have been searching for the Thiele-Small data for the 605B, but with no luck so far.
I found:
http://alteclansingunofficial.nlenet.net/Thiele-Small.html
Which includes the 605A,
But how close are these?
Maybe someone measured their units?
I found:
http://alteclansingunofficial.nlenet.net/Thiele-Small.html
Which includes the 605A,
But how close are these?
Maybe someone measured their units?
Does GPA have recent measurements? ( Great Plains Audio / Great Plains Acoustics)
They bought all the old Altec Equipment and parts after they closed.
They bought all the old Altec Equipment and parts after they closed.
Not to my knowledge, they build(t) using the tools, dies, etc., they inherited and ultimately replaced when worn out, which matches up 'close enough' IME to the online published specs. That said, the 604 series have been 'all over the map'* and unfortunately those specs are 'lost' in two flash fire cooked HDs along with lots of now Altec unobtanium I got from the S.E. Altec Distributor's in-house engineering dept..
Some good info from the late, lamented Bill Eckle's web docs and who gave me most of the really rare WE/Lansing/Altec docs, etc., I've 'lost' and certainly the most knowledgeable I've personally known:
The Wayback Machine - https://web.archive.org/web/20120122053340/http://www.wmeckle.com:80/INTRO/SMALL/Altec.htm
The Wayback Machine - https://web.archive.org/web/20090614020447/http://www.wmeckle.com:80/INTRO/LARGE/Altec.htm
* Yet sum to fit the various recommended cabs 'close enough'.
Some good info from the late, lamented Bill Eckle's web docs and who gave me most of the really rare WE/Lansing/Altec docs, etc., I've 'lost' and certainly the most knowledgeable I've personally known:
The Wayback Machine - https://web.archive.org/web/20120122053340/http://www.wmeckle.com:80/INTRO/SMALL/Altec.htm
The Wayback Machine - https://web.archive.org/web/20090614020447/http://www.wmeckle.com:80/INTRO/LARGE/Altec.htm
* Yet sum to fit the various recommended cabs 'close enough'.
Agree, close enough with various recommended cabs over the years and Altec designs.
I dont think it would be a big shot in the dark.
Looking at the various 604 models to 605 models Qts and Fs are all different of course.
But the variations are all very similar and not miles apart.
Qts is approximately .20 to .27 from 604 to 605 series,
Vas is 14 to 19 cubic feet and Fs 25 to 30 Hz
Qes Qms all behave similar too. from 604 to 605
So a one size fits all cabinet would be suitable for all those series. Just taking in the average TS values
GM is better with quick alignments
To me it is looking very much 4th order either BB4 ,C4
So just run the numbers on the 605A and that would very much seem suitable. For many of those speakers
Better make tham Mechanically happy in good airspace. So right sized box and tune slightly below Fs
basically hitting 22 to 27 Hz port, should be fine.
These are low Qts drivers. Stay away from " weasel" bass and high tuning.
No matter how you model the low frequency curve wont be glaring and bass full in a transfer function model.
These are low Qts they have a gradual quick roll off, it is just how many behave regardless.
Make the volume correct, tune below Fs . In real life, the bass is what it is and normal EQ is more than fine
for the classic sound you would expect.
I dont think it would be a big shot in the dark.
Looking at the various 604 models to 605 models Qts and Fs are all different of course.
But the variations are all very similar and not miles apart.
Qts is approximately .20 to .27 from 604 to 605 series,
Vas is 14 to 19 cubic feet and Fs 25 to 30 Hz
Qes Qms all behave similar too. from 604 to 605
So a one size fits all cabinet would be suitable for all those series. Just taking in the average TS values
GM is better with quick alignments
To me it is looking very much 4th order either BB4 ,C4
So just run the numbers on the 605A and that would very much seem suitable. For many of those speakers
Better make tham Mechanically happy in good airspace. So right sized box and tune slightly below Fs
basically hitting 22 to 27 Hz port, should be fine.
These are low Qts drivers. Stay away from " weasel" bass and high tuning.
No matter how you model the low frequency curve wont be glaring and bass full in a transfer function model.
These are low Qts they have a gradual quick roll off, it is just how many behave regardless.
Make the volume correct, tune below Fs . In real life, the bass is what it is and normal EQ is more than fine
for the classic sound you would expect.
Yeah, my 515B's are tuned 0.707x (1/2 octave) measured Fs and what I normally design to except measured Fs if driven with a high output impedance (tubes, Class A/B).
FWIW, the 605A's factory cabs ranged from ~10.31 - 17.87 ft^3, so will be interesting to see what T/S has to say for the Bs.
FWIW, the 605A's factory cabs ranged from ~10.31 - 17.87 ft^3, so will be interesting to see what T/S has to say for the Bs.
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Thanks a lot, it is confirming the impressions I also got from looking across the datasheets and the comments on correction of previous data for the T-S listings. Where the Fs went from 25 to 30Hz for the 605A.
Considering how hard it was back then to ensure consistency on pulp units, it is really optimistic to expect lower variation.
After all that was a big part of the reason of the later Bextrene succes. Manufacturability and consistency improved greatly. Today this has improved a lot for the paper pulp processes.
I have also seen some measurements on 605B's that are showing better low end than I'd initially expect.
Most of the time we are good as long as it's not a peaky high Q tuning, pushing the boundaries in too small a cabinet 😉
Checking yesterday I found there is now a GPA-europe website! - actually since September.
Considering how hard it was back then to ensure consistency on pulp units, it is really optimistic to expect lower variation.
After all that was a big part of the reason of the later Bextrene succes. Manufacturability and consistency improved greatly. Today this has improved a lot for the paper pulp processes.
I have also seen some measurements on 605B's that are showing better low end than I'd initially expect.
Most of the time we are good as long as it's not a peaky high Q tuning, pushing the boundaries in too small a cabinet 😉
Checking yesterday I found there is now a GPA-europe website! - actually since September.