So this area is not my expertise so some advice would be appreciated.
I picked up 4 of these EV TL6060DW subwoofers (not really subs as they only go down to 30Hz) but they are large enclosures and I was thinking would it be possible to replace the drivers with something that goes deeper and have it hooked up to a QSC 1500 amp and use it as a sub in my theater room?
They came out of an abandoned theater that the company I work for owns.
Well, the box is about 7.5 cu. ft. You have to keep in mind that if there is no divider in the box, two drivers will “see” half the volume of the box, just as they would if there was a divider.
So, it seems like it should be doable, if you can find a driver with a low enough Fs that will work in a 3.75 cu. ft. enclosure. Alternately, you could cover one hole and use one driver suitable for a 7.5 cu. ft. enclosure.
Disclaimer – I know just enough about this stuff to be dangerous. Hopefully some DIY experts will weigh in.
Hmmm, that's something I did not consider (closing up the one hole and using a single driver) That would certainly reduce the cost.
Now I need to find a 15" driver that won't break the bank. Are there any places in Canada that still sell drivers, wasn't there someone out of British Colombia (I can't remember the name)
With ported boxes the lower limit is defined by the box, not the driver. In this cAse the box is tuned to 40hz. As such, no matter what driver you put in it, 40hz will be its tuning. If you found a good driver for that box but with more xmax than the factory driver you might get a bit more extension without distortion, but otherwise things won’t change.
You can block a port and lower the tuning. That could increase port noise, but many find that a minor problem with subs like this. However it will still not hit 15hz.
If you want to hit 15hz in room with this box I would go with a pair of the Dayton reference HO drivers and seal off the ports. With some EQ you should see 15hz extension and high output. It won’t play anywhere near as loud at 40hz and above as the original EV but would play a good bit louder below that point.
If you want to stick with a ported box it won’t likely be possible to tune it as low as you want. The ports would need to be too long to fit in the box. You would have to curve them. Seems easier to just build a new box.
Well, I could make it a sealed enclosure but it might need some more bracing inside. It's a big box, a single driver wouldn't do the job?
Remember, I already have a PB13u so I don't need it to pound out 110db out of it.
Well, I could make it a sealed enclosure but it might need some more bracing inside. It's a big box, a single driver wouldn't do the job?
Remember, I already have a PB13u so I don't need it to pound out 110db out of it.
Well if you want my opinion, I would load it with a pair of 15’s and leave it tuned. It will pound out 140dbs, which you don’t need, but that’s just headroom then. Let the PB13 handle the low stuff and the greater efficiency of the dual 15 can handle the 35hz and up stuff. With music, that’s 99.99% of all the content. Even in movies a lot of the effects are really concentrated more in the 50hz range. That’s often where you need the big output and headroom.
If you do go sealed you won’t need to worry about more bracing. I’m assuming that comment was over concern of the increased pressure. Ported boxes have the same or more pressure than a sealed. The idea that sealed boxes have more pressure inside is a bit of a misnomer. In fact, at and around the port tuning, a ported box typically has greater internal pressure.
As for going with a single 15, that won’t change the tuning. It’s a big box so if you went with a high xmax 15 like the ultimate and blocked the ports, that would increase the LF output and lower the tuning Q. IF you leave it ported it will have no effect on the tuning and thus no effect on the low end. What it will do is cause a lumpy and boomy response.
I’ll also mention that a single ultimax 15 in a large sealed box would give your PB a run for its money. It would have more output above 35hz by quite a bit. Below 35hz and above 15hz the PB would pull ahead because it’s ported design would allow greater efficiency and that 13” driver has a lot of displacement. Below that point the 15 would excel again simply due to being sealed and having a lot of displacement. If you put a single ultimax in that box and lengthened the ports to get a tune down to 15hz (I suspect more work than it’s worth) I believe it would exceed your PB13 at all frequencies. It would have a box volume and displacement advantage.
That gives you a sense of what I mean. That is the ultimax 18 vs the PB13. The 18 is about 3-4db louder than the 15 on average so it gives you a good estimate.
Now if you stick with pro drivers and leave it tuned as is, I don’t have graphs handy to show that. But a good estimate would look somewhere between this JBL 18 (which is tuned lower at 27hz) and this JTR Growler (which has a 12 in a horn but is tuned to 40hz and is similar in output to what we are talking about for you).
If you go with Two 15” pro drivers you would have more output than this growler I believe. Especially below 40hz where you would still have a displacement advantage before exceeding xmax. Keep in mind how massive these differences are. You get 6dB more output for each powered sub you add (so additional driver and double the power, 3dB for each). Basically you would need two of the PB13’s to equal what you would have at 40hz with a setup like this (or possibly 4 depending on what 15’s and amps you used with that box). You would need 4-8 of the PB13’s to equal what you achieve at 50hz to 100hz. That’s where the “kick” of the kick drum lies so think about that.
My own opinion is that it would be nice to have that kind of output in the range above 35hz. If the ports can be extended and you can get the tune lower it’s better, but even as is I would think you would find that enjoyable.
Matt is correct about ported enclosures needing more bracing due to greater internal pressures, and that bracing should be figured into the internal dimensions to keep volume where it needs to be.
Thanks guys, the info is very helpful. I will get myself a single driver and play with the port length (easy on this box as they are accessible with the driver out) are bends allwed in a round port? I may just use some 4" PVC if that is ok to use?
Ok, so when they are back in stock I'll grab one and I will update on the progress, I guess my first step will be to do a test with the current drivers in place
Ok, so here are some pictures of the inside of the box with the top driver removed. Looking at options to either extend the ports or turn this into a sealed enclosure
I will show you some sealed options next, but...I did run some models.
Basically, you need to find a 90 degree elbow that fits over what looks to be a 5.25" port internally. I'm guessings its about 5.5" externally. I bet PVC won't work, but it could be worth a shot. You never know. It's possible that 6" PVC could be made to work. None the less, the problem you have is that the box is not deep enough internally for a sufficiently long port. My simulation suggests their claimed 40hz tuning is probably not quite right (though that might have been the f3 of the box). It appears to be tuned closer to 35hz (assuming their 9 cubic foot internal volume is correct). I suggest lengthening the port. At a minimum, you need to add 8" of length, but preferably, about 14". Anywhere in between those is fine, it doesn't make a big difference and just extends the bass. It drops the tuning to between 20 and 25hz.
As for drivers, I looked at all the basic Dayton home sub options. Here is what they look like. None of them really knock my socks off, but none of them look bad either.
The Ultimax is not in stock, but I modeled it anyway. I don't expect it to be back in stock soon, so I would personally look at other drivers. The Dayton Reference series is really good, it's just a few dB's less output than the ultimax, and...the HO version could be used in pairs. You could use two of the 15" HO's, which would give you more output, same response shape, and lower distortion.
I know you can't tell which is which, but honestly, they all modeled pretty close in this box. The Classic is the one called Dual 15 SQ and its dark Green.
The ultimax is a similar dark green and it's the one with the blip in the response at tuning. So I will say, it's my least favorite. In a 9 cubic foot box, it really needs a lower tuning, and I don't think you have the room. If I was going to do the ultimax, I would do sealed I think.
I'll work on some models for sealed as well as some pro drivers to show those options.
These subs are all modeling between 120 and 124dB's max output between 25hz and 100hz. They are still doing over 110dB at 20hz. The Dual 15 Dayton RS HO has the most output ability (124 dB max, 114dB at 20hz. Over 100dB at 15Hz.
If you wanted to tune them to 15hz (you mentioned that earlier I think) the ports would each need to be extended by 45 inches. It isn't possible, so I wouldn't try. Also note, my simulations suggest that those big ports are actually a bit small for this project. They will chuff at max output. Tuning the lower will help, but I'm showing broad/wide chuffing starting at 50hz. Regardless of woofer, it seems like the system is port limited to about 600-800 watts.
The Dual 15 Dayton RS HO Looks like the best option then, I will do some looking to see what I can find for tube elbows in PVC so hopefully I can get a bit more length to the ports. Maybe I can turn one up and the other down or is that also pointless
The Dual 15 Dayton RS HO Looks like the best option then, I will do some looking to see what I can find for tube elbows in PVC so hopefully I can get a bit more length to the ports. Maybe I can turn one up and the other down or is that also pointless
Yes the reference series is a really great sub series. It benchmarked the Peerless subs popular at the time and offers similar performance. They have really low distortion with nearly no inductive losses, especially the HF line. The HO is better in small boxes and still has really good linear performance. Also, it can handle being tuned lower.
As for the ports, see what you can come up with. I would not buy any drivers until that is settled. As for the direction, it can’t hurt. It would theoretically spread the high pressure points around the ports across the areas and lessen each.
Another thing to consider, hard bends cause more turbulence, which is already an issue for you.
It would slightly raise the tuning and slightly lower the air velocity. Since he needs to lengthen the port he could compensate some. The problem really is that he doesn’t have sufficient room in the box for ports to be long enough to be tuned much below 20-25hz. There appears to be no room for flaring on the outside but he may be able to add flaring to the inside ports. This would help some with the turbulence.
Another idea that I’m a fan of is damped tuning methods. You add a plug of open cell foam. Let’s say 5” in diameter, 2” deep, and something like 30ppi reticulated foam. This reduces the amplitude of the port but it also lowers its Q, reduces air velocity, and absorbs some high order port distortion. It’s something to consider.
Now to give you a few more options to consider. Now I wanted to provide you with more options. Most are ported since XMAX dominates the low-frequency output, these are all very similar. The Ultimax would be the highest XMAX driver, two of them in a 9 cubic foot sealed box actually does a little better than the others in sealed boxes, but the Reference is similar, within 3db's. To really see a significant increase in sub 25hz output requires moving to a $500 high xmax driver, and you would need 1000's of watts to achieve that output.
The first option to consider is to plug the ports and go with a sealed design. The same 15" reference HO drivers are the orange line. The red line is the same drivers, same volume box, tuned to 25hz. Here is my warning, while the sealed box looks like way less output if you have a good amount of room gain, the sealed may actually have the flatter response. It will have lower group delay, and by 18hz the sealed sub will have more output. If you really want the sub-20hz extension, that is the design to build, and its pretty foolproof. You can always build the ported 25hz model and the sealed can be an option, just like with the SVS you have.
THe Blue line is the Dayton PA385 pro driver with 11mm of linear excursion. It's $199 a driver, so about the same price. A pair of those in the same 9 cubic foot box and tuned to 25hz gives you similar performance below 40hz, but above that point the PA385 has more output. In fact there is a 4dB output difference at 100hz, and in practice, you will find the pro driver can handle even more power and will have less power compression due to tt's design as a pro driver. That is insane output anyway, but worth mentioning.
The green line is a LaVoce pro driver. I mention it because its an inexpensive pro driver that might be available in Canada or at a discount. It won't be any cheaper than the Dayton, but it's an Italian designed driver from a good newer company. It's a nice driver.
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Hopefully some DIY experts will weigh in.
