8 x 10 cab

[Psycho Bass Guy]

I have a mate called Jason who lives near me who is a cabinet maker and after a recent gig where I used my amp on another mates Ampeg fridge Jason and I (over a few beers) decided that it would be good fun to make one of these cabs. Another close friend is the manager of one of the larger hire shops here so access to cabs for measurements and design details is not a problem. The most obvious speakers to use would be the Eminence Legend B810.

Out of interest does anyone have any other suggestions for speakers?

Believe it or not, the cheap Jensen MOD 32 ohm guitar speakers are great, at least as good as much more expensive speakers deisgned for tuned cabinets and high s/s wattage.  I have a friend who built a homemade SVT head and cab, and he used the MODS and loves them.

The question really is "which fridge?"? The original squareback with alnico CTS 10s, or the later angled back "bathtub with towel bar" and Eminence square mag ceramics? For me it will always be the former, probably with Ted Weber's bass 10s in the absence of original 'nicos.

I used to think that the ceramic speaker/tiltback cabinet happened at the same time, but my last-aquired SVT cab is a square-back that came stock with the Eminence ceramics. It sounds just like my others, but weighs about 50lbs more.  I've never heard a tiltback SVT cabinet that sounds as good as the square one, regardless of vintage.

[Psycho Bass Guy]

Why 32?
With 8 speakers you have lots if possibilities to get your desired impedance for the entire cab.
The Deltalite II 2510 are 8 ohms individually.
...
You could still keep the four sealed compartments but just wire them differently.
As four sets of two in series, (each will be 2x 8Ohm = 16Ohm), then put all four of those pairs in parallel, to make 16Ohm / 4 = 4 Ohm.

4 ohms total

32 ohms are required for all parallel connections, which in turn, are necessary for the speaker tuning/response and sound. Modern 32 ohm speakers for guitar still have this advantage over a series/parallel array of modern bass speakers at 8 or 4 ohms. There's more to the SVT cab's sound than sheer size and number of drivers.

[Highlander]

... Gotta admit it was a juicy sound.

Understood... I've still not got around to trying the Hiwatt with the 4x10 that comes with my MAG300... mind you, I don't intend to run the Hiwatt again until I do the re-cap...  (okay... I know... something else I've not finished... story of my life, etc...)

[Freuds_Cat]

Believe it or not, the cheap Jensen MOD 32 ohm guitar speakers are great, at least as good as much more expensive speakers deisgned for tuned cabinets and high s/s wattage.  I have a friend who built a homemade SVT head and cab, and he used the MODS and loves them.

I used to think that the ceramic speaker/tiltback cabinet happened at the same time, but my last-aquired SVT cab is a square-back that came stock with the Eminence ceramics. It sounds just like my others, but weighs about 50lbs more.  I've never heard a tiltback SVT cabinet that sounds as good as the square one, regardless of vintage.

OK I will fess up, I really started this thread in anticipation of this exact response from PBG.
But I figured it would make a good topic of discussion too.   

[Freuds_Cat]

Jensen MOD10-50-32  is a 50w  whereas the Eminence B180 is 150w apparently, thoughts?

[lowend1]

Jensen MOD10-50-32  is a 50w  whereas the Eminence B180 is 150w apparently, thoughts?

The original CTS alnicos have a fairly shallow cone, a good-sized voice coil (not sure of the exact dim) and are what we would consider to be low-wattage speakers these days.

[dadagoboi]

The original CTS alnicos have a fairly shallow cone, a good-sized voice coil (not sure of the exact dim) and are what we would consider to be low-wattage speakers these days.

When wired in parallel very capable of handling rated watts of the infinite baffle SVT cab...anybody heard of the 'sweet sixteen' concept of the '40s?  I've always thought there was a connection with the SVT.  16-5 inch speakers.
http://www.roger-russell.com/columns/columns.htm#sweet

'Modern' example
http://www.rightchoicekids.com/Sweet%20Sixteen/Sweet%20Sixteen%20System.htm

The SVT cab was also the first production bass cab I can remember seeing with front mounted speakers which really increase the structural integrity of the cabinet.  Now the standard way of mounting speakers.

[Psycho Bass Guy]

Jensen MOD10-50-32  is a 50w  whereas the Eminence B180 is 150w apparently, thoughts?

Higher power handling in this case is a negative. A higher power rating means a larger voice coil, which will be heavier and thus, the speaker is less efficient. The power rating for those speakers is the thermal limit at which the voice coils burn and not a reflection on their excursion or low end. When paralleled, the cabinet has a 400 watt rating and all speakers share the same voltage and current, which is not the case with speakers hooked up in series in any form. You're far less likely to blow individual speakers that are all connected in parallel for this reason. The original CTS SVT speakers were somewhere around 70 watts each in power handling; the later Eminences are supposedly 100 watts.

Since they SVT cab has small air volume and is sealed, the lower rated resonance of the new Eminence is also immaterial. The SVT cab works on the same principle as Bag End subwoofers: the cabinet can accept low end boosts from EQ to have more bottom up to the actual thermal limit of the drivers. In a ported cabinet, the mechanical excursion limits would cause the driver damage at frequencies below cabinet tuning at far less wattage than the actual power handling of the driver.

[gearHed289]

The early SVT cabs are rated at 240 watts, so I always assumed the speakers were 30 watts each. Is that correct? They went to 400 watts when MTI bought Ampeg around 1980.

[Psycho Bass Guy]

The 240 watt "rating" was a marketing gimmick from the get-go. That tidbit and most of the other info online about the SVT cab is just repeated myth.

[lowend1]

The SVT cab was also the first production bass cab I can remember seeing with front mounted speakers which really increase the structural integrity of the cabinet.  Now the standard way of mounting speakers.

You might just be right about that - the SVT came out in '69, IIRC, and everybody was still using their Sunns, Marshall, Hiwatts, etc. - all rear loaded. The Acoustic 360 doesn't really count because the box wasn't sealed/infinite baffle, IMO.

[dadagoboi]

You might just be right about that - the SVT came out in '69, IIRC, and everybody was still using their Sunns, Marshall, Hiwatts, etc. - all rear loaded. The Acoustic 360 doesn't really count because the box wasn't sealed/infinite baffle, IMO.

The 3 full depth/width dividers that turn it into 4 separate enclosures also make it a strong S.O.B.

[gearHed289]

The 240 watt "rating" was a marketing gimmick from the get-go. That tidbit and most of the other info online about the SVT cab is just repeated myth.

Hmmm... What do you assume is the reasoning to lie about the power handling of the cabs? So people buy two? That info is right out of a 1973 Ampeg catalog BTW, not online. So what IS the actual power handling of a 70s SVT cab? I built a 410 version (2 sealed chambers...) and loaded it with speakers out of a 70s Ampeg. Would like to know the real handling ability just for the hell of it.

[Psycho Bass Guy]

Hmmm... What do you assume is the reasoning to lie about the power handling of the cabs? So people buy two?

Precisely: Ampeg must have figured if someone could afford a full SVT stack, they should go for the upsell. Decades of players using SVT's and other big heads on a single cabinet with no problems holds a lot more water than 70's ad copy.

That info is right out of a 1973 Ampeg catalog BTW, not online.

I know. Unfortunately in the 70's, Ampeg got caught up in the BS wars that were common among musical instrument amp makers. Acoustic, Fender, Gibson, Sunn, and especially Peavey (along with a bunch of others), liked to 'fudge' things too.

So what IS the actual power handling of a 70s SVT cab? I built a 410 version (2 sealed chambers...) and loaded it with speakers out of a 70s Ampeg. Would like to know the real handling ability just for the hell of it.

No one has ever actually driven an SVT speaker to destruction to get its rating and published it, but Ted Weber was shooting for a 40 watter with his unfinished CTS clone before he died. In the early days of Talkbass, an Eminence rep checked the numbers on the drivers and that's where the 100 watt rating for them came from, but a few years later, that info was apparently lost by Eminence. I know I put over 400 watts of heavily compressed tube power into my oldest cab with all stock CTS speakers and it has never barked.  I did some sweep response tests on mine years ago, but offhand, I can't find any of the raw data; I just remember being pleasantly surprised at quite a 'few nuggets of wisdom' in regards to the SVT cab being soundly proven false. You can probably safely consider your 4x10 at least a 200 watt cab as long as it is sealed.

[Freuds_Cat]

Jensen MOD10-50 voice coil is 32mm

http://jensentone.com/mod10-50.php

Eminence B810 voice coil is 50.8mm

http://www.eminence.com/pdf/Legend_B810.pdf