vintage cab design - when did it become science?

[TTA]

Even into the 1960's many car manufacturers were designing race cars based on look. Wings in f1 only started to be understood and adopted in the late 60's. By the 70's full ground effects were in use. People understood the science.

When bass cabinets were being use in the 15 bassman days was there understanding behind the design (thinking box dimensions and frequency response)? how about early ampeg/sunn/acoustic?

wondering if the 24 wide cabs was form or function for example?

i am guessing people knew their stuff when the svt/fridge came out in the late 60's.

 

[Slevage]

Even into the 1960's many car manufacturers were designing race cars based on look. Wings in f1 only started to be understood and adopted in the late 60's. By the 70's full ground effects were in use. People understood the science.

When bass cabinets were being use in the 15 bassman days was there understanding behind the design (thinking box dimensions and frequency response)? how about early ampeg/sunn/acoustic?

wondering if the 24 wide cabs was form or function for example?

i am guessing people knew their stuff when the svt/fridge came out in the late 60's.

My 1972 Bassman with diagonal 15's sounded like crap, but it was my first big amplifier and it was a Fender. My next amp was a 360. Massive and loud but….
Then a Sunn 15 scoop, later upgraded to an RB 800 wit 2-10's on top. Then various rack/speaker rigs. My current rigs are smaller, lighter and sound better, thanks to better designs and components.
When did design hit every day rigs? About 20 years ago-give or take a few years IMO.
I see SVT's at many shows, but I hear the massive PA. I saw Styx 2 weeks ago— no amps or speakers on stage though tube amps with speaker simulators were used by the guitarists. Sound and mix were as good as it gets.

 

[blr2]

There was certainly an understanding behind Jess Oliver double baffle design, so it must have been there already in the beginning of the 60's.

 

[agedhorse]

In the pro/commercial audio and cinema industries, there was a lot of scientific knowledge developing in the 1930's.

The information migrated downward in the 1950's but didn't get into the commercial MI markets until the 1970's, once TS parameters math (nomagraphs back then) was better understood.

 

[TTA]

In the pro/commercial audio and cinema industries, there was a lot of scientific knowledge developing in the 1930's.

The information migrated downward in the 1950's but didn't get into the commercial MI markets until the 1970's, once TS parameters math (nomagraphs back then) was better understood.

thanks.

was the (common number) 24 wide cab due to amps like svt's being 24 wide, or was there some design math behind it?

 

[Wasnex]

AFAIK most modern loudspeaker design is largely based on the work of Thiele and Small.

Here's a Wikipedia link you might want to read: Thiele/Small parameters - Wikipedia

Summary:

Thiele published in 1961, but remained largely unknown until his work was republished a decade later outside of Australia. This work has little real world use as it ignored enclosure losses. Small published in 1972, restating and expanding upon Thiele's work. ​

That's not to say others did not put effort into the engineering aspects of speaker design. Some designs probably even drew on the same foundational material that led to Thiele and Small's work.

Fender Tone Ring and the Ampeg Double Baffle are essentially ported cabs AFAIK. These designs pre-date Thiele and Small.

 

[ardgedee]

In the pro/commercial audio and cinema industries, there was a lot of scientific knowledge developing in the 1930's.

Was about to say something like this.

There've been scientists and engineers working on this for over a century. It took a long time for their work to coalesce into (relatively) simple formulas that provided repeatable results in cabinet design, and then, in a sense, it took even longer for speaker (the driver, cone etc) engineering to catch up, thanks to progress in the material sciences that have brought new synthetics, magnets, forming and assembly processes...

 

[Wasnex]

thanks.

was the (common number) 24 wide cab due to amps like svt's being 24 wide, or was there some design math behind it?

Intended to match the amps IMHO.

The Sunn 2000S cab was 30" wide.

Marshall 4x12s are also 30" wide.

 

[TTA]

Intended to match the amps IMHO.

The Sunn 2000S cab was 30" wide.

Marshall 4x12s are also 30" wide.

and hiwatt around 27 wide. i was reading marketing on them being built to vintage spec/dimensions and thought… "is that really a good thing?"

 

[Wasnex]

and hiwatt around 27 wide. i was reading marketing on them being built to vintage spec/dimensions and thought… "is that really a good thing?"

AFAIK vintage Hiwatt 412 were 30" wide.

Vintage spec is fine for guitar. Arguably not best for bass.

 

[fdeck]

Here's Thiele's 1961 paper:

https://diyaudioprojects.com/Technical/Papers/Loudspeakers-in-Vented-Boxes-Part-I.pdf

I think that there were a number of subtle turning points since then: Personal computers made it easy for pro's and laypeople to run modeling calculations, which I believe eliminated the need for Thiele's tabulated "alignments." The Internet resulted in massive dissemination of knowledge -- both true and false -- including readily accessible technical data for drivers. Even during my brief time on the earth, I've noticed a gradual increase in the sophistication of discussions among amateurs about speaker design. When I first joined TB, rules like "tens are fast and fifteens are deep, because physics, haha." Today, DIY'ers are sharing precise design and measurement data.

You're still on your own to separate the chaff from the wheat in the available information, as suggested by the fact that the AI chatbots can't make sense of speaker design.

 

[agedhorse]

thanks.

was the (common number) 24 wide cab due to amps like svt's being 24 wide, or was there some design math behind it?

24" was a common amp width. Actually it's a range of widths, but 24" is a good compromise for those wider heads.

 

[fretlessman71]

I am no engineer, but it seems to me that bass cabinets finally started to sound good to me when the ratio of speaker area to cabinet face area increased dramatically. Making a cabinet deeper, but no wider or taller than it needed to be to house the speakers, made a big difference in efficiency (my word to describe reaction time and tightness of sound). But that's worth exactly what you paid for it.

 

[JimChjones]

About 1972, when I started out, this was the book that UK driver suppliers touted to people who wanted to home build cabs. It actually dates back to the late 50s.

https://www.worldradiohistory.com/UK/Bernards-And-Babani/Bernards/b146-high-fidelity-loudspeaker-enclosures.pdf

Obviously it long predates Thiele and Small. There is some science there, and some of the larger designs shown are based on the sort of pro audio work AH mentions, but at the time, as a teenager, I never really made sense of all the tables and things intended to help constructing a ported cab, although it did make some use of the "Tuning" section, which actually described measuring an impedance curve. In the end though I just made a sealed box.

 

[Pdaddy1978]

Could it possibly be that 24" is exactly half a sheet of plywood?
Some design choices comes down to stuff that simple.

 

[agedhorse]

Could it possibly be that 24" is exactly half a sheet of plywood?
Some design choices comes down to stuff that simple.

Sometimes.

 

[D.M.N.]

and hiwatt around 27 wide. i was reading marketing on them being built to vintage spec/dimensions and thought… "is that really a good thing?"

AFAIK vintage Hiwatt 412 were 30" wide.

Vintage spec is fine for guitar. Arguably not best for bass.

DR103s were 25.2" wide, I think DR201s were about 28", and the cabs were 30".

Personally, I prefer 30" wide cabs, but that's purely based on aesthetics and disliking how a Sunn 2000s/Marshall/30" head looks on a smaller cab...

 

[rogypop]

Probably in the 80's in the wake of Thiele-small research on ported cabinets.
Up to then guitar and bass cabinets shared more or less the same speakers. Most cabs were either total crap or too unvieldy.

The Ampeg 810 worked since day one mostly because the sheer number of the (guitar) drivers it had so it could actually push some volume without farting out when slammed with 200 watts. The fact that it was solidly braced by being divided into four subchambers also did it a favour. Back then, and probably even now, the cabs were seldom braced internally, if at all.

 

[Ostie]

thanks.

was the (common number) 24 wide cab due to amps like svt's being 24 wide, or was there some design math behind it?

Maybe it was because you could cut a 4x8 sheet of plywood and make 4 baffle plates with no scrap. Just a SWAG.

 

[JimmyM]

There was certainly an understanding behind Jess Oliver double baffle design, so it must have been there already in the beginning of the 60's.

Bass cabs certainly were revolutionized by Jess Oliver with the B15 double baffle, but it was mostly a seat of the pants design.

The porting method he used was based on building a handful of prototypes and experimenting with the size of the slots in the inner baffle. Then the outer baffle directed the waves that came out of the port to the front of the speaker, which we now know to be an unnecessary step and an inefficient and costly way to port a cab. He had the idea that porting an otherwise closed cab would help reinforce lows and not waste the speaker energy like open back cabs.

He was right and he's rightfully held in high regard for that, but while it's still quite a beloved cab, it was made mostly by hunches that Jess had than science.