Need help with choosing a budget subwoofer - some used options included

[yonyz]

I didn't specifically ask the woodworker to assemble it for me, but I think it was obvious that I want a complete build as seen in the screenshots of the model. I didn't tell him that I want him to just cut the pieces for me.

Regarding the vent, do you mean to ask if they'll install the PVC for me?
I didn't not mention it at all to be honest. Just faxed them the screenshots.

Can I use double vents of 267.5mm instead of one with an elbow? It would create a nice symmetry.

Also, can I placed the sub on its side if I move it to another room and decide it doesn't fit the way it's built?
What I mean by that is that the longest part of the enclosure will be on the floor (the 610mm side).
Of course I'll add rubber feet for that.

It would look like this, basically:

In fact, I think I wanna copy this design in terms of the double vents and the veneer and black painting. I think it looks beautiful.

 

[rojo]

I didn't specifically ask the woodworker to assemble it for me, but I think it was obvious that I want a complete build as seen in the screenshots of the model. I didn't tell him that I want him to just cut the pieces for me.

Regarding the vent, do you mean to ask if they'll install the PVC for me?
I didn't not mention it at all to be honest. Just faxed them the screenshots.

Can I use double vents of 267.5mm instead of one with an elbow? It would create a nice symmetry.

Also, can I placed the sub on its side if I move it to another room and decide it doesn't fit the way it's built?
What I mean by that is that the longest part of the enclosure will be on the floor (the 610mm side).
Of course I'll add rubber feet for that.

It would look like this, basically:

In fact, I think I wanna copy this design in terms of the double vents and the veneer and black painting. I think it looks beautiful.

Yeah, you need to make sure they plan to build in the vent pipe before sealing it up. It'll be much more difficult to install the pipe into a completed 6-sided cube. If they refuse, then I could redesign the box with a folded slot vent.

You can do two vents, but you should use two 5mm pipes I think. (Edit: wishful thinking) What sizes of pvc pipe do you have available? I'll have to recalculate the vent length. I don't think there's enough space in the box for two 10cm double length tubes, and their add displacement might mean we'd have to make the box larger. You can flare 5mm pipe using a heat gun and a metal mixing bowl for the look you want, and flaring will also reduce turbulence / chuffing.

Yes, this sub can be laid on its side if you prefer and can spare the floor space.

 

[yonyz]

Yeah, you need to make sure they plan to build in the vent pipe before sealing it up. It'll be much more difficult to install the pipe into a completed 6-sided cube. If they refuse, then I could redesign the box with a folded slot vent.

You can do two vents, but you should use two 5mm pipes I think. What sizes of pvc pipe do you have available? I'll have to recalculate the vent length. I don't think there's enough space in the box for two 10mm double length tubes, and their add displacement might mean we'd have to make the box larger. You can flare 5mm pipe using a heat gun and a metal mixing bowl for the look you want, and flaring will also reduce turbulence / chuffing.

Yes, this sub can be laid on its side if you prefer and can spare the floor space.

I don't understand the displacement issue of the pipes. Don't two 5 cm pencils take up the same volume as a single 10 cm pencil?

I'll have to ask whether they can install the pipe for me. I'll also have to get a pipe first.

I'll start looking for a PVC pipe tomorrow. If I don't find a 10cm one, can I buy a bigger one but cut it shorter? Obviously I won't be able to ask you while I'm at a store so I want to be prepared.

 

[rojo]

I don't understand the displacement issue of the pipes. Don't two 5 cm pencils take up the same volume as a single 10 cm pencil?

I'll have to ask whether they can install the pipe for me. I'll also have to get a pipe first.

I'll start looking for a PVC pipe tomorrow. If I don't find a 10cm one, can I buy a bigger one but cut it shorter? Obviously I won't be able to ask you while I'm at a store so I want to be prepared.

Firstly, I've got to say that I was mistaken about two 5cm vents being a suitable substitute for one 10cm vent. It would actually take four 5cm vents.

The tricky balance with vents is that the thinner the inner area of the tailpipe, the faster the air moves. If it moves too fast, you get audible port noise. I've read that around 20 meters per second at 125 watts is a good target. You'll want to stay around mach 0.05 or less in any case. But a wider tailpipe requires a longer vent to achieve the appropriate tuning frequency. And if the pipe is too long, it won't fit in the box. The single 10cm pipe achieves proper tuning near the target air velocity at a length that's reasonable for the box size. Using two 10cm pipes would require you to double the length to keep the same tuning frequency.

Before I investigate whether a two-port design is possible, I'd like you to tell me what size PVC pipes you have readily available.

 

[rojo]

Slotted design. The slot vent is 2.5cm x 34.4cm x 58cm, which should result in a tuning of 23.5Hz if the net volume after displacement of the driver, amp, bracing, and the vent itself is 71L. This model uses a wood thickness of 18mm this time. SketchUp project file is attached to the bottom of this post.

I noticed how the example photo you posted had a seamless front baffle, so I designed this one with the large pieces as the front and rear baffles for the same seamless finish.

Be advised that with a single front baffle the driver will be surface mounted. If you want the clean look of a flush mount driver as shown in your photo, you'll have to do a double front baffle. The inner one will have a hole cut for the basket (282mm), while the outer one will have a hole cut for the driver's outer diameter (315mm). This would make it easier for your carpenter to round over the slot on the face of your box if you want to pursue that. But all this will add weight and expense.

With this design, the vent air velocity at 125W peaks at 19m/s at 20Hz.

 

[yonyz]

Slotted design. The slot vent is 2.5cm x 34.4cm x 58cm, which should result in a tuning of 23.5Hz if the net volume after displacement of the driver, amp, bracing, and the vent itself is 71L. This model uses a wood thickness of 18mm this time. SketchUp project file is attached to the bottom of this post.

I noticed how the example photo you posted had a seamless front baffle, so I designed this one with the large pieces as the front and rear baffles for the same seamless finish.

Be advised that with a single front baffle the driver will be surface mounted. If you want the clean look of a flush mount driver as shown in your photo, you'll have to do a double front baffle. The inner one will have a hole cut for the basket (282mm), while the outer one will have a hole cut for the driver's outer diameter (315mm). This would make it easier for your carpenter to round over the slot on the face of your box if you want to pursue that. But all this will add weight and expense.

With this design, the vent air velocity at 125W peaks at 19m/s at 20Hz.

Thanks for the redesign.

With two front baffles, do I split the 1.8 cm size between the two pieces (9mm each), or use a total of 3.6 cm?

 

[rojo]

Thanks for the redesign.

With two front baffles, do I split the 1.8 cm size between the two pieces (9mm each), or use a total of 3.6 cm?

With two front baffles, the total thickness will be 3.6cm.

 

[yonyz]

With two front baffles, the total thickness will be 3.6cm.

Thanks. Going to the local Omega Audio in a few minutes, I might be able to find an amp for cheaper.

By the way, what about the diameter of the PVC pipe? I'm OK with using just one port, it's no big deal. If I find something bigger than 10cm, will it still work?

Edit: Well that was a waste of time. Omega Audio only has a 120W amp and a 10" woofer.
Checked 3 hardware stores for that PVC, no one has it in any size. Found an online store that has PVC pipes, no the size I need but it seems that it would be cheaper to just have the carpenter do the slot port instead.

Regarding the RSL Speedwoofer you mention before, how would it perform compared to this DIY build and the PB-1000?

 

[rojo]

Thanks. Going to the local Omega Audio in a few minutes, I might be able to find an amp for cheaper.

By the way, what about the diameter of the PVC pipe? I'm OK with using just one port, it's no big deal. If I find something bigger than 10cm, will it still work?

Edit: Well that was a waste of time. Omega Audio only has a 120W amp and a 10" woofer.
Checked 3 hardware stores for that PVC, no one has it in any size. Found an online store that has PVC pipes, no the size I need but it seems that it would be cheaper to just have the carpenter do the slot port instead.

Regarding the RSL Speedwoofer you mention before, how would it perform compared to this DIY build and the PB-1000?

With the ported version, if you find something bigger than 10cm, the vent will need to be longer to achieve the same tuning.

The RSL Speedwoofer beats the BIC, Klipsch, Dayton, and all the other entry level subs mentioned at the beginning of this thread. SVS PB1000 beats RSL. Unknown how this Infinity ranks, but I would guess it's somewhere between the RSL and the SVS. The Infinity models at 103.1dB at 20Hz, 250W peak at 1m. A 300W amp would get you one additional dB over the Dayton 250W plate amp we found, but one dB difference isn't going to be audible. Ground plane RMS value at 2m would be closer to 94dB, with corner loaded real-world performance closer to 100dB depending on the room. Sound & Vision published some CEA-2010A data for the PB1000, but their testing methods for this particular subwoofer seem a little questionable. That's not to say the PB1000 is not a capable subwoofer -- only that it makes comparisons very difficult.

Here's another option for folding in the slotted build. Revised project file is attached. I think I'd prefer the folding configuration from my post last night because of the amp location, but your carpenter might find this one a little clearer to read.

 

[yonyz]

With the ported version, if you find something bigger than 10cm, the vent will need to be longer to achieve the same tuning.

The RSL Speedwoofer beats the BIC, Klipsch, Dayton, and all the other entry level subs mentioned at the beginning of this thread. SVS PB1000 beats RSL. Unknown how this Infinity ranks, but I would guess it's somewhere between the RSL and the SVS. The Infinity models at 103.1dB at 20Hz, 250W peak at 1m. A 300W amp would get you one additional dB over the Dayton 250W plate amp we found, but one dB difference isn't going to be audible. Ground plane RMS value at 2m would be closer to 94dB, with corner loaded real-world performance closer to 100dB depending on the room. Sound & Vision published some CEA-2010A data for the PB1000, but their testing methods for this particular subwoofer seem a little questionable. That's not to say the PB1000 is not a capable subwoofer -- only that it makes comparisons very difficult.

Here's another option for folding in the slotted build. Revised project file is attached. I think I'd prefer the folding configuration from my post last night because of the amp location, but your carpenter might find this one a little clearer to read.

I can't thank you enough for all the time you've put into helping me with the designs and everything. I plan to finally order the enclosure, probably using your latest design.

I did just check up the website that sells the woofer, though, and I found they have many "car subwoofers". Do any of these stand out (up to a price of 500 [those are Israeli New Shekels])?

Regarding the port, I noticed you didn't draw any "legs" to support the added wood plates for the port. Will gluing them to the side panels be enough?

 

[rojo]

@yonyz Really glad I could help!

What's the address of the website you mentioned?

Yeah, the external walls and floor of the enclosure also work as internal vent walls. Gluing them to the side panels is the idea. I'm highly interested in watching the build progress. I hope you'll take pictures along the way and at the end, let us know how it sounds. Maybe start a new build thread to document the progress.

 

[yonyz]

@yonyz Really glad I could help!

What's the address of the website you mentioned?

Yeah, the external walls and floor of the enclosure also work as internal vent walls. Gluing them to the side panels is the idea. I'm highly interested in watching the build progress. I hope you'll take pictures along the way and at the end, let us know how it sounds. Maybe start a new build thread to document the progress.

Oops. Here it is. It's in Hebrew but Google Translate (using Chrome) will do the trick.

http://www.bombuy.co.il/סאב-וופר-לרכב/סאב-וופר-ללא-תיבה

I probably won't have photos of the building of the enclosure itself, since the carpenter will do it and I probably won't be there the entire time to take photos.

I'll definitely take photos before and after the paint job / veneer application, and with / without the woofers and amp.

By the way, are you familiar with the SketchUp Mobile Viewer app? Could be useful to show the carpenter the sketch, I'm just not sure if it has the Dimensions tool.

 

[rojo]

Oops. Here it is. It's in Hebrew but Google Translate (using Chrome) will do the trick.

http://www.bombuy.co.il/סאב-וופר-לרכב/סאב-וופר-ללא-תיבה

I probably won't have photos of the building of the enclosure itself, since the carpenter will do it and I probably won't be there the entire time to take photos.

I'll definitely take photos before and after the paint job / veneer application, and with / without the woofers and amp.

By the way, are you familiar with the SketchUp Mobile Viewer app? Could be useful to show the carpenter the sketch, I'm just not sure if it has the Dimensions tool.

I had modeled many of the drivers sold on that site before and recognized most as unsuitable for home theater. I added a couple more to my not suitable list. Looks like the Infinity 1260w really is the best choice.

I've never played with SketchUp Mobile Viewer. One of the reviews says the tape measure tool is very awkward to use. I'm not inclined to spend $10 to try it out myself, though. But you can rotate the model to any view you wish, add dimensions as needed, and export to 2D (jpeg). Print 4 or 5 of those from different angles and save yourself $10.

 

[yonyz]

OK, I'll go to the carpenter tomorrow. The latest model takes into account the 1.8cm thickness and everything, correct? It's fully ready to build? (just confirming before ordering the build ).

 

[rojo]

OK, I'll go to the carpenter tomorrow. The latest model takes into account the 1.8cm thickness and everything, correct? It's fully ready to build? (just confirming before ordering the build ).

All the wood sheets are 1.8cm thick (but I used 1.8cm (H) x 2cm (W) bars on the brace, just for symmetry). I believe it's ready to build. Do you need me to go ahead and render a second front baffle with the larger cutout for the outer diameter of the driver? Maybe I can Google and figure out how to render a round-over on the exit of the slot vent as well (but no guarantees).

 

[yonyz]

All the wood sheets are 1.8cm thick (but I used 1.8cm (H) x 2cm (W) bars on the brace, just for symmetry). I believe it's ready to build. Do you need me to go ahead and render a second front baffle with the larger cutout for the outer diameter of the driver? Maybe I can Google and figure out how to render a round-over on the exit of the slot vent as well (but no guarantees).

That would be great. Thank you.

Almost forgot - what about adding polyfill? Is it doable through the amp "window" on the back of the sub? And how much is enough? Or maybe it's not really needed?

Regarding the amp:
http://www.parts-express.com/dayton-audio-spa250-250-watt-subwoofer-plate-amplifier--300-803

It says "Line-level full bandwidth (10 Hz- 20 kHz) outputs/throughputs for adding or "daisy chaining" additional amplifiers. - Does that mean my speakers will get a full signal and produce bass too?

 

[rojo]

That would be great. Thank you.

Almost forgot - what about adding polyfill? Is it doable through the amp "window" on the back of the sub? And how much is enough? Or maybe it's not really needed?

Regarding the amp:
http://www.parts-express.com/dayton-audio-spa250-250-watt-subwoofer-plate-amplifier--300-803

It says "Line-level full bandwidth (10 Hz- 20 kHz) outputs/throughputs for adding or "daisy chaining" additional amplifiers. - Does that mean my speakers will get a full signal and produce bass too?

Ok I'll add another baffle this evening when I get a chance.

Polyfil, just experiment a little and see what sounds best. Start with 1/2 to 3/4 pound and see what it sounds like. Yes, you can shove it in through either the amp cutout or the driver cutout without difficulty. If you have an old sofa accent pillow you can cut it open and use the Polyfil from that if you wish.

Your observation about the line outputs appears to be correct. You could add a pair of 80Hz high pass Fmods to your parts-express order for an inexpensive crossover solution.

 

[yonyz]

Ok I'll add another baffle this evening when I get a chance.

Polyfil, just experiment a little and see what sounds best. Start with 1/2 to 3/4 pound and see what it sounds like. Yes, you can shove it in through either the amp cutout or the driver cutout without difficulty. If you have an old sofa accent pillow you can cut it open and use the Polyfil from that if you wish.

Your observation about the line outputs appears to be correct. You could add a pair of 80Hz high pass Fmods to your parts-express order for an inexpensive crossover solution.

Much appreciated.

Regarding the Fmods, there doesn't seem to be a 80 hz version, but a 70 hz one. If we go with this method though, is there a benefit to getting a Behringer iNuke 1000 instead?

Can the iNuke power the sub AND a pair of bookshelves?

 

[rojo]

Much appreciated.

Regarding the Fmods, there doesn't seem to be a 80 hz version, but a 70 hz one. If we go with this method though, is there a benefit to getting a Behringer iNuke 1000 instead?

Can the iNuke power the sub AND a pair of bookshelves?

What powered monitors do you have? Can they play solidly at 70Hz?

A big advantage to going Behringer iNuke is that, 10 years down the road if your amp dies, you won't have to look for a replacement with identical cutout dimensions. Another is when you crank your sub loud, a plate amp can sometimes rattle; whereas going with an external amp leaves your rear baffle solid and rattle-free.

The disadvantage is that you'll have to add several items to your shopping list: a Speakon cable and terminal, RCA -> TS adapters, and RCA splitters to send signal from your DAC to two destinations.

What bookshelf speakers did you have in mind for your Behringer to power? I thought your speakers were already powered? Anyway, the Behringer iNuke is only one or two channel. Adding bookshelf speakers + a sub makes 3 channels -- one too many.

If you do decide to go with the Behringer, I'd like to rework the brace to include the rear baffle in the bracing.

 

[rojo]

Here's a model with a double front baffle with the vent exit flared. If your carpenter doesn't have a router with a bit that can round over like this, then quarter-round trim moulding similar to these might also work if you can find it with 18mm sides.

In the project file I've left the second baffle detached so you can move it if needed to illustrate dimensions. Just triple-click the detached baffle to select the entire shape as a single object to move.