Making a subwoofer?

[Stagea]

If you have an idea of your room response (either by calculation or measurement), you can probably factor that into your enclosure model. That way you'd need less equalization (and will often allow for a smaller enclosure and better power handling) to get a flat response in your room.

[spwath]

34 minutes ago, Stagea said:

When you model, it is a compromise between efficiency, physical size and power handling. Striking a good balance for your driver and room to meet your requirements is key.

Looks like the driver won't do that well, playing in the software. Any suggestions on something good under $200?

[Stagea]

23 minutes ago, spwath said:

Looks like the driver won't do that well, playing in the software. Any suggestions on something good under $200?

Reference level is providing upto 115 dB on the LFE channel. Factor in your room gain and the distance of your sub to give you a good idea of what sort of power and efficiency you'd need to hit that level (if you're building a reference level system). Most people are happy with much less than that, however.

 

Something like this if you're fine with maybe down to 15 Hz usable output.

http://www.sonicelectronix.com/item_81780_Audiopipe-TXX-BD2-15.html

 

[Stagea]

Something like this could drive it (or a PA amp that you can modify to quiet it down):

http://www.parts-express.com/yung-sd500-500w-class-d-subwoofer-plate-amplifier-module-no-boost--301-512

[spwath]

24 minutes ago, Stagea said:

Reference level is providing upto 115 dB on the LFE channel. Factor in your room gain and the distance of your sub to give you a good idea of what sort of power and efficiency you'd need to hit that level (if you're building a reference level system). Most people are happy with much less than that, however.

 

Something like this if you're fine with maybe down to 15 Hz usable output.

http://www.sonicelectronix.com/item_81780_Audiopipe-TXX-BD2-15.html

 

Is that any good? Seems rather cheap for a 15", and has big numbers (1800w) used to make people think it's better.

 

Also, I have a Yamaha em-150 ii pa amp if that is useful

[Stagea]

Just now, spwath said:

Is that any good? Seems rather cheap for a 15", and has big numbers (1800w) used to make people think it's better.

 

Also, I have a Yamaha em-150 ii pa amp if that is useful

Ignore the power rating as it's just the thermal limit of the voice coil. On a larger enclosure built for the home, a car subwoofer will reach the excursion limits way before the thermal limits are hit (unless you're asking them to play higher frequencies, which I doubt you're planning to do).

 

Home Theater subwoofers are work almost entirely on pistonic motion, so there is less "quality" to talk about outside of electromechanical linearity. In this use case, as long as the build is good enough and you have sufficient thermal capacity, then the T/S parameters should tell you most of what you can expect. 

 

The EM-150 II is too weak to make the most out of a good home subwoofer. 

 

 

 

[Stagea]

I wonder why it keeps on double posting. 

 

Relatively exotic subwoofer drivers (often used for HiFi) tend to perform well up to higher frequencies, allowing them to integrate well with smaller bookshelf speakers with very shallow crossover slopes. They are often low mass designs (making them do well with higher frequencies and more complex inputs).

 

For home theater heavy lifting, this is generally not necessary. Home theater systems run steeper slopes and generally run lower crossover points (if you have good main speakers) between the mains and the sub (100Hz or lower). The highest frequency LFE data would be around 200Hz, which even heavy drivers can handle (especially since there's not much complexity in the input signal).

[Stagea]

I failed to ask: Are you building a home theater subwoofer to begin with?

 

Generally for typical home theater, displacement and extension are king. For audio use, then it'd depend highly on your target application (there is more system variety in this field).

 

[spwath]

19 minutes ago, Stagea said:

I failed to ask: Are you building a home theater subwoofer to begin with?

 

Generally for typical home theater, displacement and extension are king. For audio use, then it'd depend highly on your target application (there is more system variety in this field).

 

I'm using it for my 4.1 system for mostly music and gaming

[Stagea]

1 hour ago, spwath said:

I'm using it for my 4.1 system for mostly music and gaming

I see. Would you still be using your small full range speakers? If so, then a smaller sub might integrate better with that system for music (especially if you do not expect substantial infrasonic output).

 

Home theater subs work great for gaming (since you get a lot of effects from games). If you have a lot of space, then that 15 inch driver with a ~6 cu-ft net enclosure (not including port volume and material volume) should be quite explosive. 

 

 

 

[spwath]

12 minutes ago, Stagea said:

I see. Would you still be using your small full range speakers? If so, then a smaller sub might integrate better with that system for music (especially if you do not expect substantial infrasonic output).

 

Home theater subs work great for gaming (since you get a lot of effects from games). If you have a lot of space, then that 15 inch driver with a ~6 cu-ft net enclosure (not including port volume and material volume) should be quite explosive. 

 

 

 

For now, but I might upgrade soon to something like the kef q100.

 

I don't really have that much space, so a smaller one would be better. I just happen to have 2 of those 15" on hand. But it looks like making even a large 6thv order bandpass sub will only get down to like 45hrz

And I can sell them for $200 each and get something nice

[Stagea]

Something like this models decently on a 2 cu-ft enclosure tuned to 20 Hz (Ported Enclosure):

http://www.parts-express.com/dayton-audio-ts280d-4-10-titanic-mk-4-subwoofer-4-ohm--295-401

 

This sub would not give you the extension of a larger subwoofer, but it would still be very formidable for a 10 incher. Make sure you get enough port area to prevent chuffing. A properly implemented infrasonic filter would also help improve overall power handling (and reduce distortion). 

 

If you want a small enclosure that plays low, consider using a passive radiator instead of a port.

 

 

[spwath]

9 minutes ago, Stagea said:

Something like this models decently on a 2 cu-ft enclosure tuned to 20 Hz (Ported Enclosure):

http://www.parts-express.com/dayton-audio-ts280d-4-10-titanic-mk-4-subwoofer-4-ohm--295-401

 

This sub would not give you the extension of a larger subwoofer, but it would still be very formidable for a 10 incher. Make sure you get enough port area to prevent chuffing. A properly implemented infrasonic filter would also help improve overall power handling (and reduce distortion). 

 

If you want a small enclosure that plays low, consider using a passive radiator instead of a port.

 

 

That one looks good. Now for a passive radiator, I would have to buy one correct? Where and how much are they?

[spwath]

9 minutes ago, Stagea said:

Something like this models decently on a 2 cu-ft enclosure tuned to 20 Hz (Ported Enclosure):

http://www.parts-express.com/dayton-audio-ts280d-4-10-titanic-mk-4-subwoofer-4-ohm--295-401

 

This sub would not give you the extension of a larger subwoofer, but it would still be very formidable for a 10 incher. Make sure you get enough port area to prevent chuffing. A properly implemented infrasonic filter would also help improve overall power handling (and reduce distortion). 

 

If you want a small enclosure that plays low, consider using a passive radiator instead of a port.

 

 

That one looks good. Now for a passive radiator, I would have to buy one correct? Where and how much are they?

[spwath]

9 minutes ago, Stagea said:

Something like this models decently on a 2 cu-ft enclosure tuned to 20 Hz (Ported Enclosure):

http://www.parts-express.com/dayton-audio-ts280d-4-10-titanic-mk-4-subwoofer-4-ohm--295-401

 

This sub would not give you the extension of a larger subwoofer, but it would still be very formidable for a 10 incher. Make sure you get enough port area to prevent chuffing. A properly implemented infrasonic filter would also help improve overall power handling (and reduce distortion). 

 

If you want a small enclosure that plays low, consider using a passive radiator instead of a port.

 

 

That one looks good. Now for a passive radiator, I would have to buy one correct? Where and how much are they?

[Stagea]

11 minutes ago, spwath said:

That one looks good. Now for a passive radiator, I would have to buy one correct? Where and how much are they?

Here's a passive radiator that's more than adequate for that subwoofer. 

https://www.amazon.com/Earthquake-Sound-SLAPS-M12-Radiator-Subwoofer/dp/B00K1GV8RM

 

If you wanna go with cheaper passive radiators (lower Xmax), you'd need more of them. 2 of these can be used for example:

http://www.parts-express.com/dayton-audio-sd315-pr-12-passive-radiator--295-496

[Stagea]

If you don't need reference-level output, the SVS PB-1000 is another option. That's only $499 and is great at that price. It won't hold a candle against a built DIY sub in output (granted you set aside a larger budget), but it'd probably cost less (since it already has an amp and a DSP at this price) and will come with a worry-free warranty (5 years). It still plays low enough to be thoroughly enjoyable.

[spwath]

24 minutes ago, Stagea said:

Here's a passive radiator that's more than adequate for that subwoofer. 

https://www.amazon.com/Earthquake-Sound-SLAPS-M12-Radiator-Subwoofer/dp/B00K1GV8RM

 

If you wanna go with cheaper passive radiators (lower Xmax), you'd need more of them. 2 of these can be used for example:

http://www.parts-express.com/dayton-audio-sd315-pr-12-passive-radiator--295-496

Any disadvantage to getting 2 cheaper ones?

[Stagea]

5 hours ago, spwath said:

Any disadvantage to getting 2 cheaper ones?

Nothing really. You'd just need more ballast since you'd be tuning two radiators. You can actually fire them in opposite directions so that they balance out each other out (preventing the enclosure from shaking the floor and moving about).

 

The main limitation is if they will work well with the enclosure volume for your driver, and how much mass they can accommodate (to get to your desired tuning frequency).

[spwath]

9 minutes ago, Stagea said:

Nothing really. You'd just need more ballast since you'd be tuning two radiators. You can actually fire them in opposite directions so that they balance out each other out (preventing the enclosure from shaking the floor and moving about).

Ok. Now I could probably fit a 12" if that could give me deeper extension.

[Stagea]

1 minute ago, spwath said:

Ok. Now I could probably fit a 12" if that could give me deeper extension.

If you can accommodate a larger enclosure, then it's okay. 

 

A suitable 15" driver can be made to do 12-15 Hz quite well when coupled with the right enclosure. Some 18" and larger subs can be used to deliver perceptible 10 Hz output (and lower). 

[Stagea]

I haven't modeled sub-woofers in a while but the last time I did it, I've not seen a production driver do better than the MTX Audio TS9924-22 for sheer capability (power handling, extension and output).

[spwath]

12 minutes ago, Stagea said:

I haven't modeled sub-woofers in a while but the last time I did it, I've not seen a production driver do better than the MTX Audio TS9924-22 for sheer capability (power handling, extension and output).

If I get rid of my bed and sell all my internal organs, I could use that.

 

Any ideas for a good 12"?

[Stagea]

3 hours ago, spwath said:

If I get rid of my bed and sell all my internal organs, I could use that.

 

Any ideas for a good 12"?

There are a lot of decent ones out there. Some will plumb much lower, though most will provide better efficiency.

 

For a single SLAPS-M12, this driver seems to model decently:

http://www.parts-express.com/dayton-audio-rss315ho-44-12-reference-ho-dvc-subwoofer--295-467#lblProductDetails

 

With the supplied ballast (255g), a 3 cu-ft net enclosure should return a response that's relatively flat down to 20Hz. Adding 145g more (400g total) should provide very strong extension down to around 17Hz, given you have an amp strong enough. 

 

You'd want something around 400W or more (clean) to do the build justice.