SWR 8x10 Quiet!?

For starters, try it with only one cabinet connected, then plug in the second. If you see a drop in volume when the second cabinet is plugged in, then there is a polarity issue somewhere. Adding a second cabinet should get something like 3-6 dB more volume.

Last year I took some in-room frequency response measurements of my Aguilar GS112 and Genzler BA12 cabinets (12” speakers in both), using a software measurement program with a calibrated mic. I was shocked to see that in a small church auditorium (a little under 4000 sq. ft.), response with both of them fell like a brick below 150 Hz, and was down a full 18 dB at 40 Hz. Forty-hertz is the fundamental of an open E string on a 4-string bass. This means that with these cabinets in this room, the lowest fundamental you’re getting is two octaves higher - somewhere way up on the G-string. Everything below that, you’re only hearing harmonics, overtones, etc.

Obviously, the situation can be worse with 10” speakers, which may not even get down to 150 Hz. (For the record: All else being equal, adding more speakers only gets more volume, not lower frequencies.)

Now, compare this to what your average guitar player is running. A typical guitar rig with one or two 12” speakers is fairly common. I haven’t taken measurements of any guitar cabinets, but I think we can reasonably assume that a typical 12” cab should also get down to the 100-150 Hz range (excluding those open-back combo amp rigs).

So here’s the deal: The lowest fundamental on a guitar with standard E tuning is 80 Hz. Well, in his situation, 80 Hz is much closer to 150 Hz than your 40 Hz is, which means the guitar player pretty much has all his low-end “grunt,” while you, the bass player, do not! So if he’s one of those players who loves his low end, that’s why you’re getting buried. This is actually a very common scenario – we get threads like this on a regular basis.

As I see it you have a couple of options, assuming you don’t have the polarity issue mentioned above.

One would be to add second amplifier, which would give you one for each cabinet, which would significantly increase your volume. Doubling up two cabs on a single amp the way you have been, it could be that the amp is simple running out of "steam" when pushed hard. If the amp has built-in limiters, that’s only going to keep things choked down.

The second would be to add a subwoofer, which would allow you to “get under him.” Maybe you can find a local pro audio shop or guitar store that does rentals, where it would only cost you a few bucks to check this out. The easiest thing would be a sub with its own built-in amplifier with an adjustable crossover. I’d suggest an 18” model, but nothing smaller than 15”. A sub is going to dig lower than a typical 15” or 18” bass guitar cabinet.

I recommend doing some research on any sub you consider renting, especially the frequency response specs. I came across one recently that had a completely ridiculous frequency response spec, something like 40 to 80 Hz. That’s practically a one-note sub! On the top end, it needs to get up to 150-200Hz, in order to blend seamlessly with your bass cabinet. On the low end, it would be desirable to find one that solidly gets down to at least 40 Hz.

Your amp head is going to need an output jack to get a signal to the subwoofer. I’d suggest setting the crossover in the 125-150 Hz range to start. Hit a low note on your bass and bring up the level until it blends with your SWR cabinet, filling out the lows you weren’t hearing (or feeling!) before. From there you can adjust the level and crossover frequency to taste.

Regards,
Wayne A. Pflughaupt

Ecclesia: Unique Arrangements of Hymns, P&W Standards, and Original Tunes
Administrator, Pedulla Club #45
Administrator, Tobias Club #133
Fretless Club #943
Big Cabs Club #23
My Rig: Stage and FOH Friendly
My Basses

 

Good suggestions so far.

A speaker phase issue came to my kind first as well. The old 9V battery test is an easy way to check it out. But running one cab at a time will likely tell you something as well. If each cab sounds more "alive" by itself, but they sound more muffled together, it could be a phasing issue.

Also, is your tone scooped? (I'm not knocking you if it is. You do you.) Sometimes a scooped tone is hard to get through in a band setting. It my rattle your windows at home by yourself. But it'll get buried with the band.... especially if your guitar players run a bass-heavy tone. If your tone is scooped, try adding some low mids back in. Low mids will kick you in the ribs.

 

It requires switching some wires on the speakers. If that's the issue, come back here with more details and we'll be able to help. If you're fortunate enough that your speaker wire is marked, it could be as simple as making sure all of the black wire (for instance) terminates on the same (positive or negative) terminal on each speaker. Sometimes whole cabs are wired in different phases. Sometimes one or more drivers in a cab can have switched wires.

 

With a little rigging you can check polarity without taking all the drivers out of the cabinets.

Assuming your cabinet has a 1/4" jack for the input:

Buy a cable with a 1/4" female on one end. Cut off the male plug and strip back the insulation about an inch to access the two internal lead wires. If you see only a single center lead with a shield, the shield will become the second lead. Unravel the shield and then twist it together. For the center lead wire, strip back the insulation to expose about 1/4" of bare wire.

Once this is done, and you have your cable with two exposed leads, touch the bare wires to a 9-volt battery. The shield should be to (-), and the center lead to (+). Watch the speakers the cabinet when you do this. You should see the cones of all speakers push forward. If the push backwards, then the cabinet’s polarity is backwards. If some speakers push in and some push out, the ones that push in are wired backwards.

If both cabinets show all the individual speakers pushing out when connected to the battery, then all is good.

Note, DO NOT keep the battery connected for more than a few seconds. If you leave it connected for an extended period of time, you run the risk of frying the speakers.

Regards,
Wayne A. Pflughaupt

Ecclesia: Unique Arrangements of Hymns, P&W Standards, and Original Tunes
Administrator, Pedulla Club #45
Administrator, Tobias Club #133
Fretless Club #943
Big Cabs Club #23
My Rig: Stage and FOH Friendly
My Basses

 

Or you could just plug in a regular speaker cable and touch the positive terminal of a 9 volt battery to the tip and the negative to the sleeve.