I recently moved to a new house, which has an area that I get to use for a dedicated home theater. It's a larger space than the old living room, and my subwoofer, a 10" Dayton Ultimax in a sealed box, just doesn't subwoof enough anymore.
So I decided to upgrade substantially and pre-ordered a pair of Stereo Integrity HT-18 v3's. I have a QSC PLX1602 (500w x2 [or 1600w bridged] into 4 ohms) to power them (for now; might get a second amp later). Now I just need to figure out what kind of box to put them in, and with that I could use some suggestions.
Box Size Constraints:
I'm planning to build a bar (as in, the kind one sits at to drink) just behind the front row of seats, so that the bar stools function as a second row of theater seating. The top of that bar is going to be on the order of 10' long, 40" high, and 18" deep. It has occurred to me that the structure of the bar would be a great place for a subwoofer, and it could be quite a large one. If I make the lower 2/3 of the box protrude from the front (screenward) side of the bar, I have close to 50ft^3 (1400L) to work with, without really taking up any otherwise-usable space.
There is also space up front with the LCR speakers. Not enough space for a second colossal sub, but enough for a decent-size ported box. So I have the option of using one driver in the bar structure, and one in the front of the room. That's what I would prefer to do if I can come up with a design that takes advantage of the volume of the bar structure with one driver, and a smaller design that should be possible to integrate with it.
Room Dimensions:
The room measures about 20'x25', with a bathroom built out of one of the corners, so it's really about 420ft^2. It has a suspended ceiling with fiber board tiles at 8' high, and the floor is carpet on concrete. The theater area itself takes up roughly 15' square, with the TV on the 25' wall, and the 20' wall on the right.
Performance Goals:
It's a home theater subwoofer and I like bass, so of course I want it to go as low as possible and be loud. Flattish to 20hz is a requirement, and I'd like to have tangible output in the mid-teens.
I've spent some time modelling boxes in Hornresp, and I've convinced it to make some squiggly lines that seem to correlate to a tolerable frequency response, but I'm realizing that I don't know what I'm doing enough to know broadly what kind of enclosure I should be trying to design. So that's my biggest question: what kind of thing should I be trying to make?
A big, standard, vented box seems to model pretty well around 22ft^3 (600L) per driver with a 14hz tune. With 10' of length available, a transmission line makes a lot of sense to me, since I could actually fit a 14hz line with one fold and no taper. That would actually be easier to build than a vented box in this case. A tapered or mass loaded line looks a little smoother in the sim. No matter what kind of box I model, it seems to want a tune between 14 and 18 hz, and the response looks pretty good with a volume around 400L, slightly better around 600L, and excessively underdamped (I think) if it's much above that. Is there anything I could do to make better use of a larger volume?
I haven't yet put in the work to learn how to make horns work without being inconceivably large. Is something like a tapped horn worth looking into for these drivers?
So I decided to upgrade substantially and pre-ordered a pair of Stereo Integrity HT-18 v3's. I have a QSC PLX1602 (500w x2 [or 1600w bridged] into 4 ohms) to power them (for now; might get a second amp later). Now I just need to figure out what kind of box to put them in, and with that I could use some suggestions.
Box Size Constraints:
I'm planning to build a bar (as in, the kind one sits at to drink) just behind the front row of seats, so that the bar stools function as a second row of theater seating. The top of that bar is going to be on the order of 10' long, 40" high, and 18" deep. It has occurred to me that the structure of the bar would be a great place for a subwoofer, and it could be quite a large one. If I make the lower 2/3 of the box protrude from the front (screenward) side of the bar, I have close to 50ft^3 (1400L) to work with, without really taking up any otherwise-usable space.
There is also space up front with the LCR speakers. Not enough space for a second colossal sub, but enough for a decent-size ported box. So I have the option of using one driver in the bar structure, and one in the front of the room. That's what I would prefer to do if I can come up with a design that takes advantage of the volume of the bar structure with one driver, and a smaller design that should be possible to integrate with it.
Room Dimensions:
The room measures about 20'x25', with a bathroom built out of one of the corners, so it's really about 420ft^2. It has a suspended ceiling with fiber board tiles at 8' high, and the floor is carpet on concrete. The theater area itself takes up roughly 15' square, with the TV on the 25' wall, and the 20' wall on the right.
Performance Goals:
It's a home theater subwoofer and I like bass, so of course I want it to go as low as possible and be loud. Flattish to 20hz is a requirement, and I'd like to have tangible output in the mid-teens.
I've spent some time modelling boxes in Hornresp, and I've convinced it to make some squiggly lines that seem to correlate to a tolerable frequency response, but I'm realizing that I don't know what I'm doing enough to know broadly what kind of enclosure I should be trying to design. So that's my biggest question: what kind of thing should I be trying to make?
A big, standard, vented box seems to model pretty well around 22ft^3 (600L) per driver with a 14hz tune. With 10' of length available, a transmission line makes a lot of sense to me, since I could actually fit a 14hz line with one fold and no taper. That would actually be easier to build than a vented box in this case. A tapered or mass loaded line looks a little smoother in the sim. No matter what kind of box I model, it seems to want a tune between 14 and 18 hz, and the response looks pretty good with a volume around 400L, slightly better around 600L, and excessively underdamped (I think) if it's much above that. Is there anything I could do to make better use of a larger volume?
I haven't yet put in the work to learn how to make horns work without being inconceivably large. Is something like a tapped horn worth looking into for these drivers?
Transmission lines are even larger and longer.
Just stick with a straight forward reflex/vented box.
Mechanically the driver is not designed to be space friendly.
The " smallest" box is around 8 cubic feet.
That is the thing about models. you can keep making the box bigger n bigger
and all looks well.
Then you have to realize just exactly how big 8 cubic feet is.
Having designed a few live audio boxes in the 8 to 10 cubic foot size.
It starts becoming a challenge to design them to fit through a standard door.
and a lot of doors are small
So keep in mind if your really gonna crawl in the 22 cubic foot zone. then build two.
44 cubic feet of boxes total will not fit through any door. The box gets built into the room.
then it never comes out.
You will have to do at least a double layer baffle and really concentrate
on bracing and side wall flexing.
Getting a flat response with a line is not very easy. you have to bring the driver
partially down the line and use damping material to maybe flatten it out.
Reflex is likely a more successful build. assuming the ports would be massive.
realistically you will likely use around 200 to 400 watts. So be a more realistic
power rating to see if you can maybe have ok port velocity. around 18 to 25 ms max.
To get low enough port velocity, and low enough tuning. Its a very large long port which
will be difficult to fit in the box as well at the full 750 watts.
Technically the efficiency bandwidth product is extremely low at 33
so the driver is more suited for sealed enclosures. All around mechanically
it doesn't seem to be designed to be accurate. no offense, its designed to move a lot.
So a sealed enclosure might be more fun.
Within reason you could build a unique reflex box, with a port that can be plugged. So you can see for yourself. or change the sound and be able to run sealed or ported.
Critically damped or a Qtc of .707 would be around 19.8 cubic feet sealed. So I would play with tuning in that volume as well. For a reasonably flat response shelf this driver
creates when its ported.
Just stick with a straight forward reflex/vented box.
Mechanically the driver is not designed to be space friendly.
The " smallest" box is around 8 cubic feet.
That is the thing about models. you can keep making the box bigger n bigger
and all looks well.
Then you have to realize just exactly how big 8 cubic feet is.
Having designed a few live audio boxes in the 8 to 10 cubic foot size.
It starts becoming a challenge to design them to fit through a standard door.
and a lot of doors are small
So keep in mind if your really gonna crawl in the 22 cubic foot zone. then build two.
44 cubic feet of boxes total will not fit through any door. The box gets built into the room.
then it never comes out.
You will have to do at least a double layer baffle and really concentrate
on bracing and side wall flexing.
Getting a flat response with a line is not very easy. you have to bring the driver
partially down the line and use damping material to maybe flatten it out.
Reflex is likely a more successful build. assuming the ports would be massive.
realistically you will likely use around 200 to 400 watts. So be a more realistic
power rating to see if you can maybe have ok port velocity. around 18 to 25 ms max.
To get low enough port velocity, and low enough tuning. Its a very large long port which
will be difficult to fit in the box as well at the full 750 watts.
Technically the efficiency bandwidth product is extremely low at 33
so the driver is more suited for sealed enclosures. All around mechanically
it doesn't seem to be designed to be accurate. no offense, its designed to move a lot.
So a sealed enclosure might be more fun.
Within reason you could build a unique reflex box, with a port that can be plugged. So you can see for yourself. or change the sound and be able to run sealed or ported.
Critically damped or a Qtc of .707 would be around 19.8 cubic feet sealed. So I would play with tuning in that volume as well. For a reasonably flat response shelf this driver
creates when its ported.
Last edited:
I would also go sealed and with a better driver for that. I'm busy also with some 12" dayton DCS305-4 and those with dsp eq can hit 20hz flat in a 34L (1.2cuft) sealed to about 105dB for one (that is at about 150w). Put a 4 of those spread in the room and you it above 110dB at 20Hz before running out of xmax. The box is 35x35x40cm in 18mm plywood. But this only works with dsp eq or a linkwitz transform circuit.
And this is only one example. Other drivers are even better (the Dayton UM series) and will need less eq in small boxes. But those drivers are expensive (above my budget for this).
And this is only one example. Other drivers are even better (the Dayton UM series) and will need less eq in small boxes. But those drivers are expensive (above my budget for this).
Member
Joined 2009
Paid Member
I also vote for sealed, but in a push-push configuration, e.g. Altair Sub (2x TRIO8's)
However, the Tapped Horn approach looks very interesting too.
However, the Tapped Horn approach looks very interesting too.
My wife isn't a big fan of huge speaker boxes either, but this isn't a speaker box, it's a BAR!
In any case, we now have an actual theater space that isn't the living room, so the theater is mine.
In any case, we now have an actual theater space that isn't the living room, so the theater is mine.
Sealed. This will go the lowest and allow for easier control.
But do note that the best way to get even bass is to place 2 or more woofers placed in the right places in the room for one driver to cancel out the modes ogf the other and vica versa.
Also a push-push sub makes a HUGE difference in terms of box load. Active reaction force cancelation.
You are at least 2 woofers short (you should have asked before pulling out the credit card).
From a quick glance the driver does look like it will be good sealed and would work in a TL (if you used the whole underside of the bar you might have enuff volume)
If the bar placement is not ideal for the woofers, you will have to rely on EQ to even things out. And EQ is used on a sealed box to dial in as low as you want. That kind of budget could get you a dozen SDX10.
Power is needed to be able to extend the bottom of sealed box. But this is a low quality brute force amplifier. If the price of the drivers you got are an indication of quality, you will not get the best of them with this amplifer.
dave
But do note that the best way to get even bass is to place 2 or more woofers placed in the right places in the room for one driver to cancel out the modes ogf the other and vica versa.
Also a push-push sub makes a HUGE difference in terms of box load. Active reaction force cancelation.
You are at least 2 woofers short (you should have asked before pulling out the credit card).
From a quick glance the driver does look like it will be good sealed and would work in a TL (if you used the whole underside of the bar you might have enuff volume)
If the bar placement is not ideal for the woofers, you will have to rely on EQ to even things out. And EQ is used on a sealed box to dial in as low as you want. That kind of budget could get you a dozen SDX10.
Power is needed to be able to extend the bottom of sealed box. But this is a low quality brute force amplifier. If the price of the drivers you got are an indication of quality, you will not get the best of them with this amplifer.
dave
I'm not sure why I would go with sealed boxes in this scenario when the box size doesn't matter. I have a couple of Hornresp models claiming I should be around 118db at 20hz with one of these drivers in a big ported box.
Member
Joined 2009
Paid Member
At the end of the day. It’s your project, why not just build what you fancy and have fun doing it.
Somewhere around 200 litres per driver for minimum EQ. Doesn’t look like it would need any EQ except to deal with the room.
dave
Member
Joined 2009
Paid Member
Member
Joined 2009
Paid Member
I built my push push on your recommendation, it’s the longest serving piece of kit that I have, so I’m rather pleased to have taken your word for it!
Do i have the right driver? I thot i saw $1100.
That cheap for an eightteen? Says the opposite about quality. That is very cheap.
That makes it even more critical to retain control which makes a sealed box an even better choice.
dave
Member
Joined 2009
Paid Member
I like sealed subs, guys. They can be great. But I'm not building sealed subs. I don't see anything in the models that makes me concerned about excursion in a vented box or quarter wave enclosure with a sufficiently low tuning frequency, and I am seeing almost 10db greater max SPL compared to sealed.
Sealed is the only enclosure type I've ruled out.
Sealed is the only enclosure type I've ruled out.
Last edited:
data-bass.com has testing and write-ups of some of the HT-18 variants as both a raw driver and in a sealed cabinet. it's worth having a look at the info on that site, and btw the author (Josh Ricci, who knows his stuff) is quite impressed with the performance/price ratio.
Member
Joined 2009
Paid Member
Here: Data-Bass: Subwoofer Measurements
Nothing wrong with narrowing down choices to vented / TL. The size of a TL may get quite long with a sub, but it can be folded. You can also do push-push in a vented / TL too.
Thing is, it’s a personal preference. The choice isn’t simply how loud it goes or everyone would pick the same. Vented boxes use a tuned resonance which produces group delay, amongst other things. There are subjective sound quality differences. Opinions differ, sealed is often credited with being the cleanest and tightest, vented with being boomy and extended which sounds impressive until you tire of it, TL somewhat in between depending on design and ripple suppression. My recommendation for sealed was based on my preferences and experience, not your, so not necessarily the best fit for you.
Edit: I’ve had good results from MLTL, mass loaded transmission line, for full range speakers. Not sure about use with a sub but could be worth looking into, kind of a combination of TL and vented reflex and can dig deeper than a BR in my experience.
Nothing wrong with narrowing down choices to vented / TL. The size of a TL may get quite long with a sub, but it can be folded. You can also do push-push in a vented / TL too.
Thing is, it’s a personal preference. The choice isn’t simply how loud it goes or everyone would pick the same. Vented boxes use a tuned resonance which produces group delay, amongst other things. There are subjective sound quality differences. Opinions differ, sealed is often credited with being the cleanest and tightest, vented with being boomy and extended which sounds impressive until you tire of it, TL somewhat in between depending on design and ripple suppression. My recommendation for sealed was based on my preferences and experience, not your, so not necessarily the best fit for you.
Edit: I’ve had good results from MLTL, mass loaded transmission line, for full range speakers. Not sure about use with a sub but could be worth looking into, kind of a combination of TL and vented reflex and can dig deeper than a BR in my experience.
Last edited:
The length is exactly what got me thinking about a TL. I'm making a 10' long thing, that's a straight 14hz line with one fold.
I too have had good results with MLTL full-range speakers. The L, C, R, side surrounds and heights in my 7.1.2 system are MLTLs with the Pluvia 7 driver. Yes, I have MLTLs mounted in the ceiling, which is quite silly. It all sounds seriously great, now I just need more bass.
I too have had good results with MLTL full-range speakers. The L, C, R, side surrounds and heights in my 7.1.2 system are MLTLs with the Pluvia 7 driver. Yes, I have MLTLs mounted in the ceiling, which is quite silly. It all sounds seriously great, now I just need more bass.
That is a quite different driver than i was looking at. First glance says sealed all the way.
Back in a sec with a size.
dave