Ohm and size for a Sub Kick

[Fishmed]

What does the Ohm for a speaker need to be to be used for a Sub Kick?
What is the largest usable speaker size for this application?

[Radardoug]

The size and the ohmage have nothing to do with it. I presume that you mean a speaker that can deal with kick drum? Find a sub unit which does the job for you, there are many to choose from. You will see by looking at the range available that they come in all sizes.

[Fishmed]

I have some raw speakers laying around and thought i would build my own.

[against88]

roll a 1x15 bass cab in front of the kick drum. done-zo.

[AlexK]

Depends on the thiel-small parameters of the drivers, and what you want to use them for.

[DeeDrive]

Originally Posted by against88

roll a 1x15 bass cab in front of the kick drum. done-zo.

Word to that, I just stuck a 15" PA speaker I had lying around about a foot or two in front of the drum and ran a 1/4" cable from the speaker to the line in on my preamp. Blending with a D112, sounded unbelievably good, would never want to record drums without it again.

Just experiment, the yamaha subkick or the NS10 have a much smaller woofer than 15", and people seem to love that.

[soundmark]

AIWA 5.5" sub driver with a big ol magnet worked for me.

[ripple_fx1]

Interesting Q....I'd venture to say the higher the Z, the better voltage transfer. The more supple the suspension, the more voltage generated. The lighter the "rotor" assembly, the quicker response to air pressure changes. 16ohm carbon fiber or plastic 8" light-duty woofer or 6" midrange? I dunno - what do the real ones use?

[SonicSkippy]

Are there any specific specs that make a good driver for this? like low moving mass, or some other quality?

[beatsnblunts]

I made one with a base of a snare stand, a tom holder clamp and a 10inch susspension ring. Wish i had a pic for ya! I think i used a 10inch jbl woofer, anyway- way to big of magnet. All i got out of it was distorted square wave type of sound. Sucked for kick only worked on bass cab if you were looking for a sub snyth-moog typ of thing.

[Wavebourn]

I used a shelf type hi-fi speaker. Output from it is HUGE despite of low resistance.

[rodabod]

Originally Posted by Radardoug

The size and the ohmage have nothing to do with it.

Really? That's interesting. So, it's not preferable to use a higher impedance speaker? How odd.

[sameal]

it's funny this thread pops up. i just got finished doing some tests on the sub-kick i decided to build a few days ago. I'm in the preliminary stages right now. just hooked the wire to the speaker to see if it'd work. and it does.

i used a 8" subwoofer from an abandoned car stereo setup. works fine from the sound of it.

my biggest question is what to use for the built in pad. the signal coming in is too hot, and an inline pad must be installed.

this site: digitaldrummer.net - Sub-Kick project, which i found on g.s. on another thread of this very topic suggests a 10k with 1k shunt, but goes on to say this may not be optimal.

my question would be, what values would be optimal?

[fixdrummer80]

I use a ns-10 woofer mounted to a homemade stand, with a 30db pad. Sounds awesome for studio or live stuff.

[Fishmed]

Originally Posted by sameal

it's funny this thread pops up. i just got finished doing some tests on the sub-kick i decided to build a few days ago. I'm in the preliminary stages right now. just hooked the wire to the speaker to see if it'd work. and it does.

i used a 8" subwoofer from an abandoned car stereo setup. works fine from the sound of it.

my biggest question is what to use for the built in pad. the signal coming in is too hot, and an inline pad must be installed.

this site: digitaldrummer.net - Sub-Kick project, which i found on g.s. on another thread of this very topic suggests a 10k with 1k shunt, but goes on to say this may not be optimal.

my question would be, what values would be optimal?

What are the specs of your speaker?
I have an 8" 2ohm sub-speaker that I think I will try.

[Les]

I might mess with this some. Seems interesting. As an acoustics type, I would consider the following factors:

1) using an unbaffled speaker
This should work fine, as it will function as a pressure gradient microphone, like a ribbon. It will have a figure 8 pattern and major proximity effect.

2) size
Smaller should be fine as long as the resonant frequency is low enough. Response will rapidly drop off below Fs. A smaller cone will likely resond better to high freqiencies as well.

3) Damping
An unbaffled unloaded speaker may have a high q resonance, resulting in a very peaky response as a microphone. So the damping at resonance might be more critical. an easy way to control this could be with a variable shunt resistance.

4) Output
Should be huge. A divider prob would be good to get it down to typical mic level. Part of that divider would also be the shunt resistance mentioned above in 3).

So, I think I would pick a smallish speaker...perhaps 6 inches or so, with an Fs at or below 40 Hz with a fairly low Qes, less than .3.

Running unbaffled, I would use a shunt resistance such that total Q is 0.7-0.9. The shunt resistance would also be part of a resistive divider network feeding a balanced microphone input.

Just some thoughts...

[mixedupsteve]

Originally Posted by Wavebourn

I used a shelf type hi-fi speaker. Output from it is HUGE despite of low resistance.

Did you just wire it up to the speaker connections on the box with the crossover still in it? I've got a lonely 6" 2 way Infinity speaker I'd like to try out.

[Fishmed]

Would a crossover work in reverse?
What if you used several smaller speakers in parallel or series?

[rogerbrain]

ever tried it on a bass cab?

[Wavebourn]

Originally Posted by mixedupsteve

Did you just wire it up to the speaker connections on the box with the crossover still in it? I've got a lonely 6" 2 way Infinity speaker I'd like to try out.

Yeah, I connected it as is, no modifications. Just to try and see if it works, or what to change if I don't like it. But it sounded great as is, on line level in (!) Fortunately it had 63 Hz resonant frequency. Detuned (awfully detuned!) bass drum sounded as if it was carefully tuned by a magic device invented by John Roberts; the drummer did not believe that! However, John did not invent his smart tuner yet then... ;)

Also, I once experimented with small speakers in plastic globes. They sounded great, as well. I suppose, bare drivers would sound as well, but drier, with shorter decay due to lower Q.

[mixedupsteve]

Originally Posted by Wavebourn

Yeah, I connected it as is, no modifications. Just to try and see if it works, or what to change if I don't like it. But it sounded great as is, on line level in (!) Fortunately it had 63 Hz resonant frequency. Detuned (awfully detuned!) bass drum sounded as if it was carefully tuned by a magic device invented by John Roberts; the drummer did not believe that! However, John did not invent his smart tuner yet then... ;)

Also, I once experimented with small speakers in plastic globes. They sounded great, as well. I suppose, bare drivers would sound as well, but drier, with shorter decay due to lower Q.

Great, I'll give it a try. BTW John Roberts invented some magic Smoke devices too.

[sameal]

Originally Posted by Fishmed

What are the specs of your speaker?
I have an 8" 2ohm sub-speaker that I think I will try.

sorry it took so long to respond.


the speaker i used doesn't have any markings on it as too ohm. i think it's a dual voice coil? it has two spots to connect up too with two wires running to the cone for each spot.

while tampering with it i wasn't too wild about the results, but it needs more testing and a better housing.

[Hashbrown]

What i want to know is this:

Should the speaker be grounded?, and use a typical shielded twisted pair?
Would this take away some bass freq.?

I have an old hi-fi set with one driver down, so i'm thinking of using the other driver to experiment.

Would it be better to take it out of the cabinet, and mount it on something?

Thanks
HB

[strdsk]

See pics of these that I've built at Tonal Eclipse Mastering Studios on MySpace Music - Free Streaming MP3s, Pictures & Music Videos in the pics section. While there are no constants, 12 inch drivers work best for me...as do 8 ohm jobs. There's a fine line between having too much mass and a slow response and having too small a diaphragm and getting thwacky sounds. I house these in drum shells that can be tuned like a resonant chamber.

[scottmckaygibson]

NS-10 woofer is the norm for this type of job. To actually answer the question, it is about 6" and rated at 8 ohms, although much of that may not matter in the end.

[Wavebourn]

Originally Posted by strdsk

See pics of these that I've built at Tonal Eclipse Mastering Studios on MySpace Music - Free Streaming MP3s, Pictures & Music Videos in the pics section. While there are no constants, 12 inch drivers work best for me...as do 8 ohm jobs. There's a fine line between having too much mass and a slow response and having too small a diaphragm and getting thwacky sounds. I house these in drum shells that can be tuned like a resonant chamber.

This one?

[strdsk]

That's one. There should also be others on there.

[Francis Vaughan]

A few thoughts from the theoretical side of things. This is a lovely example of the symmetry of the physics. This symmetry goes quite deep. A mentioned earlier, the Q of the system will influence the sound. The Theile-Small parameters or the driver, the enclosure, and the electrical environment will all influence this.

A modern dynamic speaker is designed to be driven from a voltage source. This is essentially one with zero output impedance. This looks to the speaker as if you short the input out. Running the speaker into a low level input will pretty much look like an open circuit. This can mean a quite substantial difference in final system Q. This leads to an interesting tweakable parameter. Add a variable resistance between the speaker input terminals. Varying from about 1 ohm to about 20 odd should make for a noticable change in system Q and overall character of the sound. Just playing with a few fixed value resistors might be all that is needed to tune in a desired Q. A low load impedance will begin to drop the output, but since you need to pad it anyway this isn't exactly a problem.

Speaker drivers designed for different purposes have quite dramatically different physical charateristics. In particular those designed for use in an enclosure, versus those designed to be installed in a baffle only. The obvious source of the latter being car audio. IB drivers depend much more on mechanical stiffness, whereas boxed speakers rely more on the air inside the box. IB drivers tend to have higher mechanical Q, and thus will tend to be less affected by load issues. This is also true of most sound reenforcement drivers.

Symmetry of the physics would suggest that the sonic charater of the speaker when listening to music will in some form translate to a similar character when used in reverse - with the caveat that the Q may be different due to the different load impedance as described above.

In principle you can use a multiway speaker - the crossover will work in reverse - again with an assumption of the impedance of the los being zero to get the same crossover behaviour. However the physical location of the different drivers will mean phase issues. Speakers are designed to have correct phasing of the drivers at the listener. Any other location typically isn't going to work out. Coaxial drivers tend to avoid this.

Just some very late at night ramblings.