800 Liter 21SW152 Tapped horns

[DrDyna]

Finally finished up the first pair of these tapped horns.

It's based on this design:

http://www.avsforum.com/forum/155-diy-speakers-subs/2731873-b-c-21ds115-23hz-800l-th-build.html

I've just re-oriented the exit. I wish I wasn't so lazy about dragging out the mic and laptop. I'll get around to it. Also still have to print or have the logos made. I'll drop some in room measurements over the next few days as time permits.

Edit: Oh, I should mention, there are still two more drivers for two more horns, it's just going to be a spring time project.

 

[chrapladm]

Not lazy just intelligent. You still want to be able to function also after moving said subs. As I said before great build.

Hopefully next summer I may try and build one of these subs also. Just have to finish up my other projects first.

 

[DrDyna]

I'll be curious to see what you think of it, if you go with building it.

I'll make a much longer post with some subjective stuff once I can do some tuning. I'll tell you what though, with just the basic filters, HPF around 14 hz and LPF at 70, both 48 db/oct...I don't think I'm going to have to do too much to it.

I may even drop the HPF completely unless there's a movie on, I doubt I could upset this driver unless I was really trying. I beat the snot out of them yesterday for 2 or 3 tracks and I couldn't even get the formers warm to the touch when I reached in there afterword.

 

[Todd Anderson]

Nice work... can you post an image of the front side of that massive driver? How big is it?

 

[DrDyna]

Nice work... can you post an image of the front side of that massive driver? How big is it?

It's a 21" driver. It doesn't look like it in pictures, but it's almost funny when you see it, like when you see a guy wearing one of those 4 foot long foam cowboy hats. It's got a 6" voice coil.

I pulled #3 out of the box, here she is next to one of my TC Sounds 12" woofers.

 

[Todd Anderson]

That thing is a BEAST. How much does it weigh?

Imposing looking guy, eh?

 

[DrDyna]

That thing is a BEAST. How much does it weigh?

Imposing looking guy, eh?

Yeah, they're pretty monstrous. I'm not sure exactly what the completed weight is, but if I had to guess, one full sheet of material is about 65 or 70 lbs, and each one is 3 1/4 sheets. With the driver and all the parts in it, it's probably right around 250 lbs.

They're heavy enough that when I wiggled them into position in the corner, I had to push from the bottom, and I had to put another subwoofer behind me so I could push off of it with my feet.

More than likely, these subs are going to be staying right where they are forever. The next two will be even worse, because those I'll probably make out of mdf...partially because I'm cheap, and partially because I'm actually kinda curious to A/B the two.

Edit: Unless you mean just the driver, that's about 45 lbs or so. It's actually surprisingly light for it's size with the neo motor.

 

[Todd Anderson]

DrD... I wish you’d taken some video of that maneuvering tactic!

Very impressive (and yes, the weight of the driver is totally shocking!)

 

[Matthew J Poes]

http://bcspeakers.com/en/products/lf-driver/21-0/4/21sw152

This is the driver. They are awesome. It's continuous power handling is 4000 watts and it has 16mm of linear one way excursion.

I'm a big fan of pro drivers like this for subs and jealous you can fit so many in your room. It's unreal.

My friend Mike has four of the 21DS115 in his theater in large ported boxes and that is an insane amount of clean bass.
http://bcspeakers.com/en/products/lf-driver/21-0/4/21ds115-4


Do you have HornResp simulations of these. I don't think I've ever seen a 21" tapped horn before.

It may be worth doing some listening tests to be sure but I think your idea to remove the high pass filter is reasonable. Each one of those should be capable of more than 135dbs at 70hz so I would be surprised if you managed to exceed Xmax or really for damage purposes xlim without being in pain. Those drivers are also bottomless and meant to be destruction proof. I think you will hear the problem long before you do damage.

 

[DrDyna]

http://bcspeakers.com/en/products/lf-driver/21-0/4/21sw152

This is the driver. They are awesome. It's continuous power handling is 4000 watts and it has 16mm of linear one way excursion.

I'm a big fan of pro drivers like this for subs and jealous you can fit so many in your room. It's unreal.

My friend Mike has four of the 21DS115 in his theater in large ported boxes and that is an insane amount of clean bass.
http://bcspeakers.com/en/products/lf-driver/21-0/4/21ds115-4


Do you have HornResp simulations of these. I don't think I've ever seen a 21" tapped horn before.

It may be worth doing some listening tests to be sure but I think your idea to remove the high pass filter is reasonable. Each one of those should be capable of more than 135dbs at 70hz so I would be surprised if you managed to exceed Xmax or really for damage purposes xlim without being in pain. Those drivers are also bottomless and meant to be destruction proof. I think you will hear the problem long before you do damage.

Sure thing, here's the Hornresp screens. The FR simulation is with and without lossy LE, although the response is probably closer to the non-lossy LE model (the one with stronger peaks at the ends)

 

[Matthew J Poes]

That looks good. The knee looks to be a bit under 25hz.

How did the excursion simulation look?

Pretty unreal to think about 1 watt giving you 103 db at 25hz. You could hit reference levels with this

 

[DrDyna]

That looks good. The knee looks to be a bit under 25hz.

How did the excursion simulation look?

Pretty unreal to think about 1 watt giving you 103 db at 25hz. You could hit reference levels with this
View attachment 5372

It makes pretty good noise before the signal lights on the front of the amp even flick on

Excursion at 2kW input.

 

[Matthew J Poes]

Yeah so even with 2kw you aren't exceeding Xlim, I can totally see running this without a high pass filter. Maybe a 1st order to provide a little reduction. I've seen a few scenarios where in room response of these benefit even from such a filter.

Anyway, sounds like you have some serious bass to play with now.

What was your previous subwoofer setup?

 

[DrDyna]

Yeah so even with 2kw you aren't exceeding Xlim, I can totally see running this without a high pass filter. Maybe a 1st order to provide a little reduction. I've seen a few scenarios where in room response of these benefit even from such a filter.

Anyway, sounds like you have some serious bass to play with now.

What was your previous subwoofer setup?

It's fun, that's for sure. The plan was to build two more, but after yesterday, I'm not so sure anymore. I think what I really need is some midbass modules, because that's where it seems like the system is weak.

As far as previous stuff, there's a pretty long list, but most recently I was using a pair of ultimax 15s vented, along with my tc sounds ml-od-tls, and I just picked up a pair of sealed SI HT18 d4 in about 5 cubes.

I'm pulling all those drivers out though, I'll probably go nearfield with them and build a cabinet to house them all that wraps around the back of a couch.

 

[BD55]

Those make quite the statement! The yellow is a really cool contrast. I imagine there are lots of rattles in that room to tame...or is that just your garage setup

 

[DrDyna]

Those make quite the statement! The yellow is a really cool contrast. I imagine there are lots of rattles in that room to tame...or is that just your garage setup

Hah, yeah, the garage doors rattle like mad.

This is my space for now, but in the future, I'm going to turn it into more of a den / great room rather than a garage. I'll probably cover over one of the doors for sure, but the second one might come in handy if I ever need to get these subs out of here

 

[Matthew J Poes]

Hah, yeah, the garage doors rattle like mad.

This is my space for now, but in the future, I'm going to turn it into more of a den / great room rather than a garage. I'll probably cover over one of the doors for sure, but the second one might come in handy if I ever need to get these subs out of here

While it isn't on par with what you built, I may have assembled a recent large subwoofer inside my theater because it would not be possible to easily get it in there. The room has a 30" door and a 24" walkway. Add in the thickness of the doors themselves when open and I have just 24" of total clearance really to get anything down into the theater. You could maybe fit something 28" or so if you had two big guys to lift it up and over the theater seats. Since the subwoofer and I weigh the same, that wasn't about to happen.

I made all this extra room up front for subwoofers that I can't actually get into the room!

 

[Tonto]

Have you ever considered doing a dado cut for the bracing panels? Seems like it would make glue-ups much easier. That's a big box to do by yourself. Or did those elves help out. Is that Baltic Birch? It's a shame to not stain it with a color besides black. Show off that grain! But that's just the woodworker in me. Great job on the build, thanks for sharing.

 

[DrDyna]

Have you ever considered doing a dado cut for the bracing panels? Seems like it would make glue-ups much easier. That's a big box to do by yourself. Or did those elves help out. Is that Baltic Birch? It's a shame to not stain it with a color besides black. Show off that grain! But that's just the woodworker in me. Great job on the build, thanks for sharing.

Thanks Yeah, I did consider staining it. I actually came pretty close to ordering wood dyes and trying to stain it those colors. I figure this way, if I get tired of it I can strip it off.

When I built my tqwt subs back in the day, another single fold that's very similar, but reversed taper, I did dado the baffle into the sides. I got lazy this time. Plus I've only got 6 clamps, so it takes me a couple of days to glue it up in stages anyway, so it was gonna be a pain in the butt either way.

 

[tesseract]

Man, I gotta get back over there and listen to these new goodies you have built lately, @DrDyna, including the active monitors!

 

[DrDyna]

Simulation vs reality, with and without crossover to mains. HPF defeated.

 

[chrapladm]

Looks pretty good. Did you ever try the one port option?

Sorry if it was mentioned before.

 

[DrDyna]

Looks pretty good. Did you ever try the one port option?

Sorry if it was mentioned before.

One port? Thar be no ports here, yarrr.

 

[chrapladm]

One port? Thar be no ports here, yarrr.

Not sure why I was thinking of the Skhorn. Sorry about that.

 

[DrDyna]

Not sure why I was thinking of the Skhorn. Sorry about that.

hah, no big deal, it's my own fault for entertaining the idea of building so many things outloud, lol.