First of all, many thanks to Erich at DIY Sound Group. This is the third pair of subs I've built from flat packs and they've all been great. Without DIYSG, I probably never would've attempted a sub build.
My previous subs were Dayton 18" HO's in 4 cu/ft sealed boxes. I was happy with them. But then, I started planning to install an electric AT screen, and I wanted something that would be a bit closer to the wall. Plus, I always wondered...should I have gone ported vs sealed???
The Stonehenges fit the bill with a relatively shallow depth as well as having the benefit of raising up my center channel so that it's almost in line with my L/R's.
So far they sound great. I'll be taking measurements in the next couple days and posting comparisons of the sealed 4cu/ft boxes vs the Stonehenges in my room. Stay tuned.
Thanks. The flat packs are really easy to assemble. It was the size and weight of these boxes that became difficult, especially after I lined the inside with denim insulation.
My first thought was to veneer them like I did with my previous set of subs but these were so big and heavy that I painted them instead. They're not perfect if you look up close, but from a few feet away they look nice.
After I get my screen and projector up and running, I might go back and build some grills for them.
I have all of my AV equipment in the adjoining bedroom hidden in a closet and controlled with my Harmony remote and IR repeater. From what I saw, it didn't look like the Behringer could be operated with IR. Plus I had already run two 50 ft runs of subwoofer RCA cable through the floor across the garage and up through the bedroom for my previous subs. I'm also a MAC guy and it looked like I needed a PC to set up the dsp in the Behringer.
I know the Behringer and Crown offer more bang for the buck than a plate amp. But I paid more for convenience in the end. And the 1000 watts each seems to be plenty.
I just ran some measurements using Fuzzmeasure and the same equipment I used when I ran measurements with the sealed boxes last year. I'd like to get some opinions on them.
The blue graph is the Dayton 18 HO's in the old 4 cu/ft sealed boxes. I measured them probably a year ago and from what I remember I applied a boost around 20hz with the plate amp. (Phase of both subs was "norm.")
The green graph is the new Stonehenge boxes in the same locations. The phase of both subs is set to "norm" and I applied a small cut at around 53hz. (Not a big result but helped a little.)
The red graph is the Stonehenge's in same locations with the sub in the front set to "norm" and the phase of the rear sub set to "rev."
And the last graph, is an overlay comparison of all three.
The measurements I'm getting from sealed vs ported appear very close. It's making me question if all of the work I put into the new boxes was worth it.
They pretty much have the same response. Try different sub placements. I know it'll look off, but try it if you can. Maybe put both subs up front? Move the rear sub to the left?
When I had the sealed subs, I tried every combination of dual subs I could think of--both in various setups up front, both in various setups behind the couch and multiple setups of one up front and in the rear.
This front-back setup gave me the best overall response.
Interesting results. Not really what I expected to see. I wouldve guessed the lower end wouldve rolled off faster at the port tune on the stonehenges and that there would be a a couple more db gained at port tune and a little higher (looks like there is only a db or so gained there). I think showing graphs with both configurations without any EQ would be ideal, but I know thats not necessarily possible now that things are switched over. Thanks for sharing your results!
Yeah, it's not really possible since I only kept the best measurements I could get from the sealed boxes when I measured them back in May. From what I remember I gave them a PEQ boost at around 20hz. And that was with 500 watt plate amps. I now have 1000 watt plate amps on the Stonehenges.
Anyway, I went back and took the measurements again. Here is a comparison--Sealed boxes is blue, Stonehenges with a slight cut at 53hz is red. Crossover is set at 60hz--same as it was before. This yielded a slightly better FR.
The results are so close that the differences are negligible, in my opinion. Which is disappointing because I went to a lot of trouble to build the new boxes. But if I hadn't, I would have always wondered, "what if?" Either way, they sound great.
That looks a little better. It looks like the ported are about 2-3db higher at port tune. And if you take away the gain from the boost on the sealed plot, you'd probably see the db gain at around 19-20hz that would be expected. All that said, I boost my sealed subs as well, and after seeing the minimal differences, I cant really see a reason to switch. If nothing else, you saved me the time and trouble by answering "what if" for me!
nice work on your subs, though I'm not sure what you are asking about.
you mentioned that you applied eq to the sealed boxes and are showing that they have a response similar to the ported enclosures with no eq--that is what one would expect.
ported cabs have more output for the same amount of amp, so your new system won't run out of headroom as fast as the old system.
the difference would be really clear in series of sweeps where each one was +5db. the sealed sub would compress out on the low end quite a bit before the ported.
Thanks. I guess I was expecting to see a big difference in the graphs on the low end but that makes total sense. I wasn't thinking about headroom vs compression. I was listening to them again just now and they sound great. And on big movie scenes, I'm sure the extra headroom will come in handy.
It's also important not to forget that a room dominates low frequency response. Your room is the majority of what your low frequency response looks like, so no matter what subwoofer you put in there, no matter what design, the response will look highly similar. Differences will come mostly when you move the subs around or add additional subs which then energize the room differently and excite modes in different ways.
As was already mentioned, going ported is going to add 5-6 db of output in the low end from an efficiency standpoint. It may reduce compression but that is also tied to the port size and thermal limits of the driver. The sealed system should have thermally stressed the system more than the ported, so then I think the real issue is port compression issues. I'm personally very curious about these same boxes but I think the issue is, are those ports large enough to have inaudible chuffing noises at the levels achieved in the sealed system. My guess is yes, otherwise people would have complained about the box, but since you have the boxes maybe you can test and see.
i helped in the study of and testing of some band pass ported subwoofer designs that used many small ports and special reticulate foam filters lining the ports, as well as a special ported qb3 aligned subwoofer based in a tc sounds 3000 driver, also with a smaller than ideal set of ports using duct liner and reticulate foam. All in an attempt to improve flow and reduce noise. Experiment was an utter failure and left me with five very useless boxes and the manufacturer needing to switch to passive radiators. While the experiments were not successful, with a correctly sized port, I think the same approach would still reduce some of the higher frequency noise coming from the ports. You could always give it a shot.
It's also important not to forget that a room dominates low frequency response. Your room is the majority of what your low frequency response looks like, so no matter what subwoofer you put in there, no matter what design, the response will look highly similar. Differences will come mostly when you move the subs around or add additional subs which then energize the room differently and excite modes in different ways.
As was already mentioned, going ported is going to add 5-6 db of output in the low end from an efficiency standpoint. It may reduce compression but that is also tied to the port size and thermal limits of the driver. The sealed system should have thermally stressed the system more than the ported, so then I think the real issue is port compression issues. I'm personally very curious about these same boxes but I think the issue is, are those ports large enough to have inaudible chuffing noises at the levels achieved in the sealed system. My guess is yes, otherwise people would have complained about the box, but since you have the boxes maybe you can test and see.
i helped in the study of and testing of some band pass ported subwoofer designs that used many small ports and special reticulate foam filters lining the ports, as well as a special ported qb3 aligned subwoofer based in a tc sounds 3000 driver, also with a smaller than ideal set of ports using duct liner and reticulate foam. All in an attempt to improve flow and reduce noise. Experiment was an utter failure and left me with five very useless boxes and the manufacturer needing to switch to passive radiators. While the experiments were not successful, with a correctly sized port, I think the same approach would still reduce some of the higher frequency noise coming from the ports. You could always give it a shot.
How much PEQ did you give the sealed subs? 6 dB of boost requires 4 times as much power as no boost. So if you had a 500W plate amp, when you maxed out the subs before, you were using 500W around the PEQ frequency and only 125W the rest of the time. Now you get the same output with 125W at all frequencies, including the old PEQ frequency, so you can crank the volume even higher and get more bass at every frequency.
I don't remember for sure but it was probably around 5-6 db's of PEQ and at the time I had 500 watt plate amps. Now I'm using 1000 watt plate amps on the ported boxes.
Thanks. I have a much better understanding of the advantages now.
It sounds similar except I feel the low, low frequencies more. Now I haven't done a direct, blind A/B comparison of course, but it feels like there is more room-shaking bass. I don't listen at reference levels too often like many people on the forum, but the system sounds great and I'm happy I made the upgrade.
The flat pack is very easy to glue up. Just take your time and do it step by step. If I can do it, I assure you, you can do it. If you don't own any clamps, you might want to consider buying a couple or borrowing from a friend. I've built six flat pack subs from DIY Sound Group so far and I'm glad I made the investment in some clamps.
I lined the interior of the box with denim insulation. I used spray adhesive which holds it very well, but it's really messy and you have to make sure you do it outdoors or in a well ventilated area and you should wear a breathing mask. If I did it again, I might look into another way to glue it on.
The box is very large and heavy so having a friend to help move it around when you're finishing it is a big help.
Other than that, it's pretty straightforward. Start a build thread when you get going.
Did you use wood screws to attach the sub? And do they line up with the Stonehenge "pillars" so that you just screw them in?
I assume pilot holes are drilled first.
Phillips head or hex head?
Include a washer?
thanks, I have NO idea what I'm doing and any tips attaching the driver to the cab are appreciated!!!
Did you use wood screws to attach the sub? And do they line up with the Stonehenge "pillars" so that you just screw them in?
I assume pilot holes are drilled first.
Phillips head or hex head?
Include a washer?
thanks, I have NO idea what I'm doing and any tips attaching the driver to the cab are appreciated!!!
When I ordered the drivers from PE, I also bought some of the black, pan head screws. I can't remember what size but ask a PE rep. I did drill pilot holes first and I made sure the pilot holes lined up with the pillars underneath. Part of the genius of the design is that the driver bolts directly onto the pillars underneath. I did not use washers and didn't need them. Other people might like them and many other people like using other types of fasteners, like hex bolts etc. But for me, the pan head screws worked just fine.
Nice and neat. Now I have an idea to start with my own subs.
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