Double Bass Amplifying without amplification...

[Matthijs]

Wouldn't the board where you put the end pin at the start of the horn basicly be the throat if the horn is closed at that end?

 

[Matthijs]

I was thinking of something like this. A circular platform, the bass is positioned in the middle. The bracing/support inbetween the two boards shape two exponentional horns. I did try to do a picture but failed. I'll try again sometime later

 

[drurb]

Wouldn't the board where you put the end pin at the start of the horn basicly be the throat if the horn is closed at that end?

Yes, but if the bass is placed on top of the cavity then you're not really driving it as a compression driver would.

 

[longfinger]

Thanks! It wasn't a complex build by any means, though. It wouldn't be hard for anyone to knock up, even with just good hand tools and some planning.

You're right, it was snare/hi-hat/ride, guitar & bass (playing standards); normally (if I'd had the PA there) I would have sung but not brought the drums as it's just too much to lug around (although I occasionally do both if the gig requires it (and pays sufficiently!)). The audience did like it; we usually get a good reception. Sold a couple of CD's & got a bit of coin in the hat; nice. No video, though, sorry; I'm never keen to leave a camera several metres away unattended! There's some older stuff on my website (Paul Sun - Jazz Vocalist: Videos), but nothing particularly recent; I've been pretty slack in keeping that up to date & fresh.

Nice.

If there is some money there in this gig, I would not abandon it so quickly. Some alterations of playing could make the situation more workable perhaps without having to carry a lot of staging gear.

some things to experiment with...

- ditch the full drum kit. Too much to carry and much louder acoustically than the other instruments. Try just the snare drum on a stand to play standing up, or use those marching band harnesses. Or even washboard percussion.
- sing using old style musical theatre projection
- songs: move towards simpler folk sounding soungs. Old standards played musical theatre style or folk style.
- guitar, use a capo, simpler triad chords, and get the volume from open string jingle-jangle. (if possible, use full bodied acoustic guitar without built in p/u + preamp.)
- bass , the usual
- if bassist and guitarist could sing backups while you sing, all the better.

Lower the "pain" involved, and the "pleasure" that remains might be enough to make the gig still worthwhile.

Eventually, this gig might be a better opportunity for a brass band, but until then...

 

[GrowlerBox]

... - ditch the full drum kit. Too much to carry and much louder acoustically than the other instruments. Try just the snare drum on a stand to play standing up, or use those marching band harnesses. Or even washboard percussion.

+ 1. A cajon can work pretty well under these sorts of circumstances.

 

[Nagrom]

Just do what we did before they invented the amplifier... It really wasn't all that long ago in music history.

 

[swingingoodtime]

Nice.

If there is some money there in this gig, I would not abandon it so quickly. Some alterations of playing could make the situation more workable perhaps without having to carry a lot of staging gear.

some things to experiment with...

- ditch the full drum kit. Too much to carry and much louder acoustically than the other instruments. Try just the snare drum on a stand to play standing up, or use those marching band harnesses. Or even washboard percussion.
- sing using old style musical theatre projection
- songs: move towards simpler folk sounding soungs. Old standards played musical theatre style or folk style.
- guitar, use a capo, simpler triad chords, and get the volume from open string jingle-jangle. (if possible, use full bodied acoustic guitar without built in p/u + preamp.)
- bass , the usual
- if bassist and guitarist could sing backups while you sing, all the better.

Lower the "pain" involved, and the "pleasure" that remains might be enough to make the gig still worthwhile.

Eventually, this gig might be a better opportunity for a brass band, but until then...

Thanks for the thoughts. Just to clarify, it's not a full drum kit; just snare, hi-hat & ride, so it blends well with the other instruments.

I'm also not sure that changing repertoire, singing louder for 3 hours & training the other muso's to sing along necessarily falls into the basket of 'less pain'...

And although there's money; it ain't much & not really worth getting the muso's off-side in the end.

 

[swingingoodtime]

I was thinking of something like this. A circular platform, the bass is positioned in the middle. The bracing/support inbetween the two boards shape two exponentional horns. I did try to do a picture but failed. I'll try again sometime later

I get what you’re saying: Two circular discs stacked with a gap between them, that gap forming the 360 degree horn mouth with the throat starting from the centre, with a shaped filler in between to produce the exponential curvature from the centre to the outer edges of the disc(s).

Les (drurb) is right in that driving a horn from a diaphragm that plays directly into the throat is completely different from trying to excite a side wall of the horn. Of course, if you cut a hole in the centre of one of the discs and placed a diaphragm there (for the endpin to rest on) then it would be firing into the throat but (i) you’d need a diaphragm that would need to support the weight of the bass but be flexible enough to vibrate down to the desired lowest frequency & (ii) the upper frequencies would get lost as a result of the 90 deg bend.

In addition, the things to remember about horns is that for best results:

Horns need to be a length equivalent to (at a minimum) a quarter-wavelength of the lowest cutoff frequency you’re trying to produce (actually, apparently you’ll only hear down to the lowest freq x 1.25 (eg, 40Hz cut-off, 48Hz audible), so aiming for an audible frequency means for a longer horn that will support the cutoff frequency). A 40Hz horn would be 2.15m (qtr wl) long! Even with mild foreshortening (which would sacrifice fidelity, which is already compromised by the fact that you’ve used a qtr wavelength instead of a full one) , it would still be about 1.8m-ish so:
(i) A circular platform would therefore need to be 3.6m in diameter (the radius being the horn length)
(ii) Ideally the mouth circumference needs to be equivalent to the FULL-wavelength cutoff frequency at a minimum, and the mouth the corresponding area for a circular mouthed straight horn (like a trumpet). The area of a 40Hz horn mouth with an 8.6m circumference would be 5.9m sq. The circumference of your 3.6m disc is 11.3m. To ensure that your mouth area is the same, the gap between the two discs would need to be 52cm (5.9/11.3 = 0.52).

So you’re looking at a 3.6m wide, 0.52m tall platform. Of course, you could scale these dimensions down for a higher cutoff frequency, but then you run into the problem that the 90deg bend in the throat is killing off much off the higher frequencies to begin with, which may defeat the purpose of the exercise to begin with...

 

[Matthijs]

I get what you’re saying: Two circular discs stacked with a gap between them, that gap forming the 360 degree horn mouth with the throat starting from the centre, with a shaped filler in between to produce the exponential curvature from the centre to the outer edges of the disc(s).

Les (drurb) is right in that driving a horn from a diaphragm that plays directly into the throat is completely different from trying to excite a side wall of the horn. Of course, if you cut a hole in the centre of one of the discs and placed a diaphragm there (for the endpin to rest on) then it would be firing into the throat but (i) you’d need a diaphragm that would need to support the weight of the bass but be flexible enough to vibrate down to the desired lowest frequency & (ii) the upper frequencies would get lost as a result of the 90 deg bend.

In addition, the things to remember about horns is that for best results:

Horns need to be a length equivalent to (at a minimum) a quarter-wavelength of the lowest cutoff frequency you’re trying to produce (actually, apparently you’ll only hear down to the lowest freq x 1.25 (eg, 40Hz cut-off, 48Hz audible), so aiming for an audible frequency means for a longer horn that will support the cutoff frequency). A 40Hz horn would be 2.15m (qtr wl) long! Even with mild foreshortening (which would sacrifice fidelity, which is already compromised by the fact that you’ve used a qtr wavelength instead of a full one) , it would still be about 1.8m-ish so:
(i) A circular platform would therefore need to be 3.6m in diameter (the radius being the horn length)
(ii) Ideally the mouth circumference needs to be equivalent to the FULL-wavelength cutoff frequency at a minimum, and the mouth the corresponding area for a circular mouthed straight horn (like a trumpet). The area of a 40Hz horn mouth with an 8.6m circumference would be 5.9m sq. The circumference of your 3.6m disc is 11.3m. To ensure that your mouth area is the same, the gap between the two discs would need to be 52cm (5.9/11.3 = 0.52).

So you’re looking at a 3.6m wide, 0.52m tall platform. Of course, you could scale these dimensions down for a higher cutoff frequency, but then you run into the problem that the 90deg bend in the throat is killing off much off the higher frequencies to begin with, which may defeat the purpose of the exercise to begin with...

You got my idea. Fitting in some kind of diaphragm in the shape of a smaller disk of a thinner material might work, but I don't think it is really nescesary as the major vibrations will be in the center and this contraption would be some kind of an compromise/combination of the design we saw in this thread and a horn. The top plat would work as one giant radiator, but with the larger part of the sound emanating from the middle. It's just an idea, but I don't think you'd need a pure one point sound source. Sure there will be all kinds of phase interaction between the top plate and the waves in the 'horn', but we're not going for hifi here. Chances are the lower frequencies won't be affected that much.

Also we don't need to go down all the way to 40hz. It's doubtfull the inital vibrations are strong enough in that region. I even doubt 80 hz would be nescesary, as what we want to achieve is some loudness in a live outdoor environment. I'd be happy with some boost down to maybe 160 hz. This makes it alot easier to get at a reasonable size.

 

[Matthijs]

To be more exact: I was thinking of two 'horns' emanating from the centre: each forming a 180 degree mouth. A 1.8 m radius (yes I know, that's not really portable) would be just enough for a 160 hz cutoff frequency and there won''t be an angle in the horn. The size of the horn mouth could be easilly achieved.

I don't think you'd need a lot of high frequencies. What you'd want is some extra thump inbetween 160 and below 1 k.

The big question for me is if there's enough vibration coming from that endpin to start with.

Besides: this is giving me ideas for an i-pod table

 

[Mike Goodbar]

Also, don't forget that just because you're having trouble hearing yourself, it doesn't mean the audience can't hear you. I've discovered that the bass tends to throw the sound forward. I was playing an ampless gig one night, working my butt off to be heard over the guitar drums and sax. During break, a guy who was sitting across the room recommended that I turn my my volume down.