Hello experts!

I would like to run a cheap experiment. I will take a 10 or 12" subwoofer
speaker, and wish to make it pulse from 0 - 20 Hz. I would like to do this
relatively cheaply.

Needs:

1) Function generator - would be nice to have a digital display, but not
necessary. I see function generators all over eBay. It seems I can buy
anything that can produce my desired frequency range. (?)

2) Amplifier - I have NO idea what specifications I need here. I just wish
to make the speaker pulse at the low frequencies. I would like a good
pulse, a muddy vibration would not be good. What do I need to look for,
what should my spec. concerns be?

3) Subwoofer - I would like something relatively lightweight that I can
easily hold in my hand. I'm guessing that isn't an issue, as the cheaper
the speaker, the smaller the magnet, and the lighter it is.

4) Connectors - I see function generators tend to have BNC outputs. do I
look for BNC to RCA connectors at Radioshack? How should I connect the
generator to the amp?

Thanks for the advice,

John

Don't do this.
You will throw the voicecoil of the woofer right out of the housing.
There is no way to make a 0 Hz signal. You must have a low frequency cutoff,
and the speaker/enclosure/drive circuitry must designed to handle this
cutoff.

"JohnB" wrote in message
...
Hello experts!

I would like to run a cheap experiment. I will take a 10 or 12" subwoofer
speaker, and wish to make it pulse from 0 - 20 Hz. I would like to do
this
relatively cheaply.

Needs:

1) Function generator - would be nice to have a digital display, but not
necessary. I see function generators all over eBay. It seems I can buy
anything that can produce my desired frequency range. (?)

2) Amplifier - I have NO idea what specifications I need here. I just
wish
to make the speaker pulse at the low frequencies. I would like a good
pulse, a muddy vibration would not be good. What do I need to look for,
what should my spec. concerns be?

3) Subwoofer - I would like something relatively lightweight that I can
easily hold in my hand. I'm guessing that isn't an issue, as the cheaper
the speaker, the smaller the magnet, and the lighter it is.

4) Connectors - I see function generators tend to have BNC outputs. do I
look for BNC to RCA connectors at Radioshack? How should I connect the
generator to the amp?

Thanks for the advice,

John

"JohnB" wrote in message

Hello experts!

I would like to run a cheap experiment. I will take a 10
or 12" subwoofer speaker, and wish to make it pulse from
0 - 20 Hz. I would like to do this relatively cheaply.

0 Hz is DC, an impractically low frequency for attempting to
reproduce audio. Think of it as raising the barometric
pressure in the room and keeping it there.

As a practical matter, 3-5 Hz are possible lower limits for
your experiment.

You want to do this experiment in a reasonably small room,
as that makes generating bass easier.

Needs:

1) Function generator - would be nice to have a digital
display, but not necessary. I see function generators
all over eBay. It seems I can buy anything that can
produce my desired frequency range. (?)

A low cost option - use the audio interface in your PC to
reproduce digitally-generated test signals.

2) Amplifier - I have NO idea what specifications I need
here. I just wish to make the speaker pulse at the low
frequencies. I would like a good pulse, a muddy
vibration would not be good. What do I need to look for,
what should my spec. concerns be?

You want an amplifier with good subsonic response. Many
common amplifiers are designed to roll-off response below 20
Hz.

3) Subwoofer - I would like something relatively
lightweight that I can easily hold in my hand. I'm
guessing that isn't an issue, as the cheaper the speaker,
the smaller the magnet, and the lighter it is.

Lightweight and low bass don't go together. Neither does
cheap.

4) Connectors - I see function generators tend to have
BNC outputs. do I look for BNC to RCA connectors at
Radioshack?

They have 'em.

How should I connect the generator to the amp?

If you're really fixed on that function generatgor, use
regular shielded cable. Use a regular audio cable with a
BNC-to-RCA adaptor.

JohnB wrote:
Hello experts!

I would like to run a cheap experiment. I will take a 10 or 12" subwoofer
speaker, and wish to make it pulse from 0 - 20 Hz. I would like to do this
relatively cheaply.

I don't know why you'd want to do this, but I'll answer the questions
where I have an answer.

I also suggest you post in:

rec.audio.tech

Needs:

1) Function generator - would be nice to have a digital display, but not
necessary. I see function generators all over eBay. It seems I can buy
anything that can produce my desired frequency range. (?)

2) Amplifier - I have NO idea what specifications I need here. I just wish
to make the speaker pulse at the low frequencies. I would like a good
pulse, a muddy vibration would not be good. What do I need to look for,
what should my spec. concerns be?

3) Subwoofer - I would like something relatively lightweight that I can
easily hold in my hand. I'm guessing that isn't an issue, as the cheaper
the speaker, the smaller the magnet, and the lighter it is.

For the amp and the subwoofer speaker driver, you could just buy a
powered 10" or 12" sub from eBay.com or elsewhere. Then you could take
the subwoofer speaker driver and hold that in your hand.

4) Connectors - I see function generators tend to have BNC outputs. do I
look for BNC to RCA connectors at Radioshack?

Try: www.RadioShack.com

How should I connect the
generator to the amp?

Thanks for the advice,

John

"JohnB" wrote in message
...
Hello experts!

I would like to run a cheap experiment. I will take a 10 or 12" subwoofer
speaker, and wish to make it pulse from 0 - 20 Hz. I would like to do
this
relatively cheaply.


0 Hz is not going to be possible, try for 5 Hz.

Needs:

1) Function generator - would be nice to have a digital display, but not
necessary. I see function generators all over eBay. It seems I can buy
anything that can produce my desired frequency range. (?)

You don't need to buy anything like that, you can use free test tone
generators that are downloadable. Try search for test tones.


2) Amplifier - I have NO idea what specifications I need here. I just
wish
to make the speaker pulse at the low frequencies. I would like a good
pulse, a muddy vibration would not be good. What do I need to look for,
what should my spec. concerns be?

Something that doesn't roll off as many amps are designed to do.
A price point would be helpful to better advise you.

3) Subwoofer - I would like something relatively lightweight that I can
easily hold in my hand.

I guess that depend on how strong you are, but as a rule, low bass and
lightweight do not go together. The most affordable 12" woofer I know of
capable of 20 Hz or lower is the Adire Audio Shiva @ $125.00 IIRC.
www.adireaudio.com


I'm guessing that isn't an issue, as the cheaper
the speaker, the smaller the magnet, and the lighter it is.


But if it doesn't have enough excursion, it won't get to the lower
frequencies.
I don't think you'll find a woofer capable of the very low bass that has a
magnet less than 40 oz. Typically a decent low bass driver will weigh 10lb.
or more.

4) Connectors - I see function generators tend to have BNC outputs. do I
look for BNC to RCA connectors at Radioshack? How should I connect the
generator to the amp?

Use a regular audio cable with a BNC-to-RCA adaptor, these are available at
Rat Shack and elsewhere. You should use shielded cable.



Thanks for the advice,

John