Ampeg SVT-210 Av frequency response. What's the truth?

[Buzz Grim]

I'm curious about the actual frequency response of the Ampeg SVT-210 AV cab. Ampeg lists it on their web site as -3db at 58Hz-5kHz and -10db at 40 Hz.
Bass Gear Magazine reviewed the cab in issue No.4 and had a measured response graph but unfortunately I can't clearly read the db scale on the left hand side of the graph on my PDF version of the article. It looks to me like the low end response starts to drop at around 120-140Hz and is down about 12db at 60 Hz. This would be nowhere near the published spec.
The -3db at 5kHz looks about right though.
Am I reading this graph wrong? Are the printed versions of this graph legible?
What is the actual -3db point for this cabinet?
thanks
Buzz

[billfitzmaurice]

Originally Posted by Buzz Grim

What is the actual -3db point for this cabinet?
thanks
Buzz

Off the top of my head 58Hz seems right. The -3dB point has no relationship with the maximum sensitivity of the cab, nor the average sensitivity of the cab. It has to do with the sensitivity within the region of the woofer's pure pistonic function, a concept that's completely lost on most manufacturers. Ampeg is an exception, and they do have a history of publishing honest specs.

[Buzz Grim]

Bill,
Did you see the frequency response graph in the Bass Gear Magazine review?
I'd just like your opinion of what it's showing.
Thanks
Buzz

[Buzz Grim]

Bill,
The cab I'm asking about is the small sealed 2x10 which has about .67 cu ft gross internal volume / driver.
I got interested in this partly from looking at the graphs on your web site for the sealed cab with Eminence Alpha 10's. I've also been looking at the suggested cab designs that Eminence gives for the Legend BP102 and the Legend B810.
None of these speakers seem to go that low in such a small cabinet.
Part of what's odd is that Ampeg gives the same -3db at 58 Hz spec for the 8x10 cabinet which has over 1 cu ft. / driver. It looks like the Eminence Legend B810 will meet this in a box that size so I'm not questioning that.
I'm questioning the -3db at 58Hz on the mini cab spec based on what I think is shown in the Bass Gear Magazine graph and also based on what I've seen from other Eminence drivers in a similar size box.

[Sartori]

Isn't the 210AV just a fourth of the 810, which as I recall is internally divided into four 2x10 chambers anyway?

[Buzz Grim]

Originally Posted by Sartori

Isn't the 210AV just a fourth of the 810, which as I recall is internally divided into four 2x10 chambers anyway?

No , The Svt210 AV is a scaled down version of the 8x10 cabinet which is as you say divided into 4 internal chamber. One 210 AV is smaller than 1/4 of an Ampeg 8x10 cabinet. Both are sealed cabinets. With the same drivers a smaller cabinet should have less low end extension than the larger cabinet. I'm not saying that the speakers in the 210AV are the same as in the 8x10 but I don't see any Eminence speakers that will give -3db at 58hz in a box as small as the 210 AV. Part of my curiosity is that I'm weighing building something against buying 210AV's. If the 210 Av's really have an F3 of 58 Hz they use special drivers that are different than anything I can buy from Eminence.

[JimmyM]

Well they are different drivers for sure. They're smaller magnets and they don't handle quite the power that the 810e drivers handle. Low end response, though, seems only slightly lighter than the 810e. If I add a pinch of bass boost, I can get the low end response out of them that I need. I'll be the first to tell you that they're not a cab for everyone, but I freakin' love them. I used a couple of them with my SVT Tuesday night, and it was all kinds of awesome.

[Seans]

As JimmyM has said they are certainly smaller magnets in the 210 than the current 810e and I think the cones are smaller too. If you're looking at making a cab, perhaps check out the heritage speakers, not sure of the part number or spec's, but I'm sure it's known here.

[tombowlus]

Originally Posted by Buzz Grim

It looks to me like the low end response starts to drop at around 120-140Hz and is down about 12db at 60 Hz.

Yes, you are reading those numbers correctly. That is how it measured for us.

[lookiel]

Well then Mr Bowlus,
Your measurements must be off since
Ampeg
NEVER
Lies
!
(unlike them dudes in Denmark)

[Jerrold Tiers]

Low frequencies are notoriously difficult to measure.

Long wavelengths, big open areas needed to avoid reflections, etc.

And there is a big difference depending on what environment is used..... is the assumption half space? Or 1/4 space? Measurements at LF can be off quite a bit if the measuring space is different for one measurement vs a different one.

I have no idea which set of numbers is correct in this case, but I know that the idea was always to get a correct result and be able to publish truthful results as specifications. The equipment to get good results was available (we used a TEF setup and had a large test volume, plus an available outdoor area).

There seems to be such a large difference in the numbers here that it is puzzling..... especially when smart users seem to report good performance, which you would not expect from the BG results.... Apparently someone is wrong, but I have no clue who.

it looks to begin with as if there is a difference in measuring space, at least. But I don't know the facts, and I don't know exactly how the BG tests (or the Ampeg tests) were conducted in the case of this cab.

[JimmyM]

All I can tell you is I've got a lot of experience with them on gigs, and if BG's measurements are accurate, it sure doesn't sound that way to me on a gig. With a little boost of the bass knob, not very much at all to be honest, the low end response is very similar to my vintage 810 minus the bigness of a cab with 4x the speakers, and mic'ed into a PA with my Heil PR40, I'm hard pressed to tell the difference.

[bassboysam]

going to revive this thread instead of starting a new one. If the 210AV is 1/4 of the 810 does that mean that it is a sealed 2x10 cab? I'm pretty sure it is but I just want to make sure.

Also Jimmy, Ampeg claims that it is a good replacement for an 8x10 in the studio. Do you agree, can it produce the same vibe at more sane volumes? We are going back to the studio in November and I need something to record with that will sound similar to my live sound which is heavily dependent on my 8x10

[tombowlus]

Originally Posted by bassboysam

going to revive this thread instead of starting a new one. If the 210AV is 1/4 of the 810 does that mean that it is a sealed 2x10 cab? I'm pretty sure it is but I just want to make sure.

Also Jimmy, Ampeg claims that it is a good replacement for an 8x10 in the studio. Do you agree, can it produce the same vibe at more sane volumes? We are going back to the studio in November and I need something to record with that will sound similar to my live sound.

Yes, the SVT-210AV is a sealed enclosure.

[gnjpowell]

Designing a cab to work well and sound great in real-world use may be different from designing a cab to measure and test well in the lab. Personally I'd rather have a cab that works well and sounds good in real environments. Ampeg has _some_ experience with this.... I don't often do gigs in the lab.... Think I'll buy one and find out for myself!

[bassboysam]

I picked one up this weekend and I am very very impressed. it sounds a lot like my 8x10, maybe a little brighter but it just took a slight tweak of my tone knob and it is pretty much bang on. Not very loud and no way I would ever be able to play a gig with one or even two of them but for the studio and home it is perfect.

[billfitzmaurice]

Originally Posted by Buzz Grim

Bill,
Did you see the frequency response graph in the Bass Gear Magazine review?
I'd just like your opinion of what it's showing.

I have not. But as I already stated f3 and f10 bear no relationship to the highest point of the chart, nor any averaged figure either. It's relative to the Transfer Function Magnitude. I don't know what the driver is in this cab, but the Transfer Function Magnitude of the SVT driver, for instance, is approximately 93dB, irrespective of the cab it's in. The cab is responsible for the f3 and f10 that's realized.

[Buzz Grim]

Originally Posted by tombowlus

Yes, you are reading those numbers correctly. That is how it measured for us.

Thanks for responding Tom. I still find it hard to believe that the -3db at 58 hz figure given by Ampeg is correct. For comparison, the Ampeg number is very close to the -3db at 56 hz. figure given for an Audiokinesis Thunderchild 112. I'm not saying that the Ampeg cabs aren't great little cabs, just that I don't think that it's likely that they can be so small and loud and go as deep as claimed by Ampeg.
The Bass Gear Magazine review graph seems to support this and looks to me to show about what you could reasonably expect from such a small cabinet with decent efficiency.

[billfitzmaurice]

Originally Posted by Jerrold Tiers

Low frequencies are notoriously difficult to measure.

Not really. All you need is an open field and a spot 50 feet or more from any buildings. You first measure the cab ground plane, the mic literally a half-inch from the ground, two to four meters away. That gives you the half-space result below the baffle step frequency. Then you put the cab on the ground facing up, the mic suspended above it, at least two meters away. That gives you the half-space result above the baffle step. Then you combine the two to get the full bandwidth half-space measurement.
Of course this is a bit of a chore in the city, or in winter, but it's still easier than building an anechoic chamber.

[beans-on-toast]

Originally Posted by billfitzmaurice

it's still easier than building an anechoic chamber.

I used to have one available that I used for recording. You get a strange sensation being in one, different from that of an ISO booth, when the door closes.