Just a thought on this subject.

I'm sure we've all felt the rumble of a subwoofer or anything else with a low frequency. This made me think of Newton's third law. For every action there is an equal and opposite reaction. Same thing with shooting a gun and the recoil. So if these bass frequencies are shaking us then there must be more energy required to shake us.

You probably got something there Danny.

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Brian
Work is energy per unit of time. If I have to move a speaker cone back and forth 20,000 a second, I think I am doing more work than if I do it 20 times a second.

I know I am missing something in my analysis, but I'm not sure what yet.

I'm guessing it might boil down to how much air you're moving in a given amount of time. Since the bass speaker only moves at 20Hz, it has to travel a lot further to move the same volume of air? So maybe you'll end up doing a lot of work to move that 20Hz speaker the distance it needs to go to make a noise?

That's maybe why those subwoofers look like they're about ready to jump out of the enclosure when you drive them with a couple hundred watts (and it takes a fair bit of wattage to move those cones).

I know those low frequencies get absorbed by a lot of things and that might be why we tend to feel rather than "hear" them.

Mel

Ben
I was told there'd be no math......

He he.

Brian
Work is energy per unit of time. If I have to move a speaker cone back and forth 20,000 a second, I think I am doing more work than if I do it 20 times a second.

I know I am missing something in my analysis, but I'm not sure what yet.

Hi Brian,

Let’s see if I can help or just confuse some more. I think it’s a matter of size…

It’s relatively difficult for a 12” cone to make a 20,000 Hz sound but relatively easy to make a 20 Hz sound.

From the opposite perspective, it’s easy for a 1” tweeter to make a 20,000 Hz sound but quite difficult for it to make a 20 Hz sound.

In the case of a guitar/bass speaker we have a speaker of a given size, let’s say a single paper coned 12”. And it operates well in about the 60-2,500 Hz range.

But it does need to move more air to make that 60 Hz note than it does to make, say, a 1,000 Hz note. The wavelengths are longer. Off the top of my head I’d guess about 8 feet at 60 Hz versus 10 inches at 1,000 Hz (don’t quote me on the numbers). Plus our ears are less sensitive to low frequencies, say below 100 Hz (google Fletcher-Munson curves). I think low E on a 4 string bass is 40 Hz. And I think that people just tend to like bass played louder than a sharper, more piercing high note.

So that 12” cone needs to work harder (i.e., needs more power input) to produce a bass guitar note of 80 Hz of the same perceived loudness (or to yield the same smile on a face) as a regular guitar treble note of 1,000 Hz.

Does that help or just confuse?

You feel bass sounds rather than hear them because our ears are not made for them as they are for mids and treble, because we communicate in these frequencies. Bass frequencies are not easily absorbed, you can hear them for great distances. A trebly sound is associated with something near by.

The Exotic Guitar of Kahuna Kawentzmann

You can get the boy out of the Keynes era, but you can’t get the Keynes era out of the boy.

Last edited: Mar 14, 2009 14:56:22

Nice explanation, I'm good now.

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man, this thread is an awesome micro-course on psycho-accoustics!

so when will we be diving into the"Haas effect"?

JonW had it right . It's the amount of "in and out" that's the key variable. The term for this is "speaker excursion". Bass speakers (and keyboard and PA speakers as well) allow for more excursion than guitar speakers do, so as to be able to reproduce the lower frequencies without damage.

Any guitar amp can be used for bass so long as a bass speaker is used with it. Whether the resulting sound is any good is a matter of personal preference. You won't hurt the amp, though.

In those old Vintage days we so love, the only difference between guitar and bass amps was usually that bass amps eliminated the 'verb and trem. Modern bass amps tend to have different tone stacks than guitar amps, specifically oriented towards bass tones.

So long as the Bandmaster is played at practice levels, though, it should be OK.

There is also the issue of open-backed vs. closed back cabs. I have heard it said- though I can't personally vouch for this- that a bass speaker can be damaged by using it in an open-backed cab, as the speaker excursion to the rear is not damped by the air pressure in the back of the cab. Closed back cabs are said to provide added damping of the rearward speaker excursion. "Tuned" ports are often added to closed cabs, to allow this extra pressure to escape and provide additional bass tone.

This may be more myth than anything, but one might be careful about putting a bass speaker in an open cab for this reason.

If I wax pot my pickups, will they work underwater?

Nice bit of cabinetry there, Jon! I like your closed/open back idea.

I don't play bass, so I'm not the one to ask about optimum set-ups for that. I'm just starting a rebuild of a P-Bass clone, as I figured it would be good to have a bass around the house for plunking away on, and for those late-night impromptu jams when friends stop by.

I would think, however, that 2 15"s might be a bit much unless you're planning on some serious gigging with the rig. Either a single 15" or a pair of 10" speakers ought to be plenty for most uses, or so my bass playing buddies would tell you.

If I wax pot my pickups, will they work underwater?

JonW
Thanks newey. I’m happy with the looks and sounds of the cabinet. But my real goal was to build it and still have 10 fingers afterwards, so I could play guitar.

Good idea to have a bass around. I may do the same. I’ve been thinking about this more lately. And I’m wondering what the ideal cabinet and speaker setup might be. I could just buy the speakers and build another cabinet. Maybe go with pine or something of the sort next time, to keep the weight down. Maybe build the cabinet and speakers and run it with the Bandmaster for a while. If I want to get louder, just keep the same cabinet and speakers but pick up a Showman or Dual Showman. Not sure what type of speakers to use, though. The only person I’ve seen here using what I might guess to be an ideal bass amp setup is WoodyJ. And near as I can tell, the speakers he uses are not being made any more. I’ve searched and read all the bass setup threads here. I’m open to suggestions. Maybe I should start a new thread. In the mean time, I’ll ask…

Anyone got any recommendations for the ideal bass speakers or cabinet configurations?

Bass players are a different breed than guitar players from a gear standpoint. While a majority of guitar players stick with gear whose designs date back to the 50's and 60's...Strats, Teles, Les Pauls, Fender, Vox and Marshall tube amps..many bass players seem to gravitate toward the "latest, greatest" gear available, especially regarding amps. While the Ampeg SVT with a 8x10 cabinet is still the standard for the big stages, there is an unbelievable array of bass amps to suit the needs of every bassists style. Speaker choice is also complex, depending on what you want. Everything from cabs with 5" drivers to 18".

With that said, I'm still pretty old school bass-wise. Duck Dunn, James Jamerson and Bob Bogle are my bass heroes. Yes, I am a huge fan of the Electro-Voice bass speakers, but they are getting hard to find and have become very pricey. E-V's current bass speaker appears to be the DL 12X and DL 15X, available at U.S.Speaker, site link: http://www.usspeaker.com/homepage.htm

The latest thing in bass speaker technology is the neodymium magnet. The neo magnets weigh a lot less than conventional alnico or ceramic ones and in my experience perform just as well. I have two Mesa bass amps with 12" neos, and they sound fabulous. Eminence seems to be the new leader in bass speakers, and they are priced very reasonably compared to a new E-V or an old JBL that will probably need reconing. SWR, Fender and other bass amp manufacturers are using Eminence speakers nowadays, so they must be decent.

Speaker size? That's a personal preference thing. 10's give a tight, focused sound. 18's (to me) are way too flabby. I like either a single or two 15's for stage work, and 12's in the studio.

Cabinet size/volume is very important. Although a Dual Showman is a very good bass rig with proper speakers, it would sound better if the cabinet were deeper (front-to-rear) as it is voiced for guitar, not bass. There is a lot of science involved in speaker cabinet design and porting that is way over my head. But I will say that tone-wise, the single 15" Fender clone cabinet that Eddie Katcher built for me several years back is the best-sounding single 15" bass cab I've ever played through. It is the same size as the very early single 12" tone ring Showman/Bassman cabinets (30" wide. 20" high), but I had Eddie make this one 15" deep (instead of 11.5") to get more cabinet volume. It's all you need in all but the bigger venues. Here's a pic:

Jack Booth
(aka WoodyJ)

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Last edited: Mar 24, 2009 17:57:52