Not exactly DIY, but the same approach with stage subs

[mk1981]

The most cost-effective way to add lots of high quality bass to a HT setup recommended here and elsewhere, is to make DIY subwoofers, getting largest diameter speaker available (15" or 18" if not larger), build an enclosure based on T-S parameters of the speaker and pair it with an outboard amplifier and a miniDSP.

The prospect of making an enclosure by myself is daunting. I don't have ready access to woodworking tools and fixing a mistake would be costly, so I was looking at the options available to me in Europe (sadly, I don't see premade subwoofer enclosures for home use, in contrast to the US).

I recently came across listings of lightly used or even unused (due to COVID) stage subwoofers. The price range is incredibly low like $150 for a pair of Wharfedale Pro SVP-18B up to $500 for a pair of Wharfedale Pro Delta X18B in perfect condition. The 18-incher in DLX series (released in between these two) is somewhere in between cost-wise.

Looking at Wharfedale's page for X18B here, the frequency response is 38 Hz-1.5 kHz ±3 dB, then goes down to 30 Hz at -10 dB. I figure if it's a major third down for each -7 dB, it would go to 24 Hz at -17 dB and just below 19 Hz at -24 dB, all at 99 dB. Pretty solid.
Looking at its manual, no reflex ports are visible, so it's probably a sealed speaker. The older model SVP-18B has three ports on the front, this one doesn't.

I won't be playing the subwoofer at 99 dB, I figure the peak SPL they ever reach is 100 dB, and will usually be played at no higher than 85 dB.

Anyway, aesthetics aside, I was thinking any of these large sub-bass units could be an excellent subwoofer in the home theater when paired with a 800 W amplifier and supplied through a miniDSP.

It seems like such an easy solution that begs to be paired with something like Behringer NX1000 or NX3000 amplifier and a miniDSP 2x4. A cosmetic cover would probably be necessary to make it living room-compatible, but it's not impossible.

What am I missing? Are DIY solutions, sometimes costing several times more per speaker, better in any tangible way, considering it's bass we're talking about?

 

[Wayne A. Pflughaupt]

What am I missing?

It doesn’t get very low – 38 Hz is basically it’s usable extension. That’s fine for pro audio use, but not so great for a home audio subwoofer. If you can live with that, then you’ll be happy with it.

The prospect of making an enclosure by myself is daunting. I don't have ready access to woodworking tools and fixing a mistake would be costly, so I was looking at the options available to me in Europe (sadly, I don't see premade subwoofer enclosures for home use, in contrast to the US).

If you can live with cuts that aren’t perfectly straight, all you need is a jig saw and a battery-powered drill.

Why would a mistake be “costly?” How much does wood cost in Europe??

Regards,
Wayne

 

[mk1981]

Yeah, it was later explained that this is actually a vented subwoofer, not a sealed one.

Wood is probably the same as in America. I guess it might even be cheaper (and less impacted by the price increases) because it's not used for construction as much.

Thing is, I can buy MDF in bulk or cut to my requirements. By bulk I mean they're large sheets that I can't really fit in a car (few people own a pickup truck, I sure don't), so buying pre-cut is the only way it can be done right.

Gluing the pieces together into a basic cube is not a problem. I guess I'd need a few clamps, nothing big.
Painting it requires consumables and very simple and inexpensive tools.
Screwing in feet and the speaker isn't a problem. Wiring it isn't a problem. Even making a grille isn't much of an issue (and I'd have to make a grille with children around).

The problem is cutting the large hole for the speaker (or speakers). The small hole for the socket is easy. It's the large one that's potentially a problem since it needs to be finished properly with an inset edge for the speaker to sit in. I couldn't seem to find this done as a service and I don't feel like spending several thousand on tools just to make a couple of subwoofers. Sadly, while there definitely were 15" and 18" subwoofers sold on the market, it seems none of them break since I'd expect at least a couple damaged ones to be resold just for the cabinet. No such luck.

 

[Wayne A. Pflughaupt]

You don’t even need clamps. It should be screwed together anyway. I like using flat-head sheetrock screws because they easily countersink flush. Use lots of glue on assembly, it should be squeezing out everywhere. Easy enough to clean up the excess with a wet rag.

Cutting the hole for the speaker is no big deal. I’ve done it myself, and my carpentry skills are basic at best. The speaker you get should include a template you can trace on the wood. After that, it’s an easy cut with a jig saw. The speaker will come with a gasket that will give an airtight seal the speaker to the box I’m sure there are some DIY speaker building sites you can find with more tips.

Regards,
Wayne