DIY Sub Upgrade - 4 x 18" SI - AVS Forum
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post #1 of 125 Old 03-28-2013, 07:10 PM - Thread Starter
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I am looking to upgrade, but I am not sure what to do next. Right now I have a pair of Dayton 15" HF subs in ~4.7cuft sealed boxes in my terribly shaped living room. They run through a MiniDSP to an EP4000 amp. I want to upgrade to get more output without losing any sound quality. At my listening position, these hit ~106dB (playing music) when the amp starts to clip, which is more power than the subs are rated for. I think it is partly due to being in kind of a null in my bad room; in parts of the attached dining area and kitchen I was getting 113dB. The built-in subs in my Definitive BP7000 towers are louder.

I have considered a bunch of ideas, but I haven't found anything that wouldn't result in a pair of 10cuft towers in my living room. I could build another pair of Daytons or turn my current pair to into F20's, but then I would have huge boxes. I would like to use the ~$400 worth of drivers and boxes I have, but maybe some higher output subs in a ported box? I'm not sure.

How would 4 sealed boxes compare sound output and quality-wise to a pair of F20's? At least in my apartment now, sub 20Hz ability isn't that important. I high pass the pair now at 19Hz to limit excursion anyways.



Here are some measurements without Audyssey, with Audyssey, and with Audyssey and Dynamic EQ of my pair now without the HPF. There is no MiniDSP EQ involved. I am pleased with the current setup, but would like some more output.


Living room: Definitive BP2000TL, CLR3000, BPVX, Quad SI 18" subs
Bedroom: Definitive BP30, CLR2000 Also have had: BP7000SC, BP8B, BP10B, BPX, Dayton 15" HF subs, Rythmik F15
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post #2 of 125 Old 03-28-2013, 07:35 PM
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The middle graph looks really good... Is that measurement taken at your listening position? If so then you do not have a null. What you have are subs that are extremely clean and flat. Here's a little experiment to try, take that middle response, and with your miniDSP add a boost of 6db centered at 50hz with a Q of 2.0 and give it a listen then report back.


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post #3 of 125 Old 04-03-2013, 08:15 PM - Thread Starter
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Originally Posted by Jay1 View Post

The middle graph looks really good... Is that measurement taken at your listening position? If so then you do not have a null. What you have are subs that are extremely clean and flat. Here's a little experiment to try, take that middle response, and with your miniDSP add a boost of 6db centered at 50hz with a Q of 2.0 and give it a listen then report back.

That is taken from the listening position on my couch, about 8-10ft away from the subs. I finally had time to play around with them today, and adding that boost does make it louder. What is the point of just boosting that one spot compared to just turning the subs up though?

I was playing with WinISD and it looks like no other cheaper sealed sub is going to give me significantly more output. An SI 18 only modeled 3dB higher with the same power. It looks like 4 HF's will have more output than 2 of anything more powerful I looked at.

I also noticed, even running less power, I would need a high pass filter. I was hoping to go without one with less power using 4 of them, but even with a 20Hz HPF they exceed xmax. It seems like no matter the power pretty much, I would need a HPF. It seems like a waste of the sealed subs playing down to 10Hz if I have to high pass them. Unicron-WMD runs 8 off of 2 ep4000 amps and doesn't run a HPF I don't think and he gets a ton of 10Hz output. That should be about 425W per sub which looks like it exceeds xmax by a lot at 10Hz. Am I modeling something wrong?

Finally, it looks like the only thing worth upgrading to would be F20s. From what I read, it looks like an F20 would be as loud as 4 sealed HF's, so turning my 2 into F20s would be about 12dB louder than my current setup or 6dB louder than 4 HF's. If I have to highpass the sealed boxes at 20Hz, then they would go no lower than the F20's would anyways. If I were to go this route, how would the sound quality of F20s compare to the sound quality of the sealed boxes? How would Iimit the amp output to 300W to work with the F20? 4 F20's would work ampwise, but that would probably be too much box in the living room, haha.

Living room: Definitive BP2000TL, CLR3000, BPVX, Quad SI 18" subs
Bedroom: Definitive BP30, CLR2000 Also have had: BP7000SC, BP8B, BP10B, BPX, Dayton 15" HF subs, Rythmik F15
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post #4 of 125 Old 04-04-2013, 07:14 AM
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Quote:
Originally Posted by bradthebold88 View Post

That is taken from the listening position on my couch, about 8-10ft away from the subs. I finally had time to play around with them today, and adding that boost does make it louder. What is the point of just boosting that one spot compared to just turning the subs up though?

I was playing with WinISD and it looks like no other cheaper sealed sub is going to give me significantly more output. An SI 18 only modeled 3dB higher with the same power. It looks like 4 HF's will have more output than 2 of anything more powerful I looked at.

I also noticed, even running less power, I would need a high pass filter. I was hoping to go without one with less power using 4 of them, but even with a 20Hz HPF they exceed xmax. It seems like no matter the power pretty much, I would need a HPF. It seems like a waste of the sealed subs playing down to 10Hz if I have to high pass them. Unicron-WMD runs 8 off of 2 ep4000 amps and doesn't run a HPF I don't think and he gets a ton of 10Hz output. That should be about 425W per sub which looks like it exceeds xmax by a lot at 10Hz. Am I modeling something wrong?

Finally, it looks like the only thing worth upgrading to would be F20s. From what I read, it looks like an F20 would be as loud as 4 sealed HF's, so turning my 2 into F20s would be about 12dB louder than my current setup or 6dB louder than 4 HF's. If I have to highpass the sealed boxes at 20Hz, then they would go no lower than the F20's would anyways. If I were to go this route, how would the sound quality of F20s compare to the sound quality of the sealed boxes? How would Iimit the amp output to 300W to work with the F20? 4 F20's would work ampwise, but that would probably be too much box in the living room, haha.

I personally like ported subs better for home theater, even over tapped horn subs such as the F-20. I have a buddy that just built an F-20 and it gets absolutely crazy loud, but, that is not my cup of tea. There are so many possible combinations of things you could do, which would make it hard for myself, or anyone else to tell you what to do.

If it were me, I would either build some ported boxes for those Dayton HF-15's or sell them and get a pair of Dayton HO18's or SI18's.
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post #5 of 125 Old 04-04-2013, 09:01 AM
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Did you have a goal in mind before you built the subs?
What is your goal now?
You said you measured 106db? What frequency is this? There are so many questions before anyone is able to help you.

If you know how to use winISD, then model the excursion difference between increasing input wattage versus adding a boost at 50Hz.
It should be fairly obvious once you look at the graphs.
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post #6 of 125 Old 04-04-2013, 04:57 PM - Thread Starter
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I had a Rythmik F15 before this and my goal was to fix the terrible 20-40dB dips in the frequency response and hopefully get a little more output. Output was the same, at the non-scientific 106dB during music test. 120dB without losing any sound quality seems like a good goal now (based off the almost 110dB peak below), but I think only changing drivers and using 4 of them would get me that far, or maybe the F20's, so mid 110's might work. I measured my room to be about 3400cf I believe. What other questions are there?

Excursion difference wasn't really what I was asking about boosting 50Hz, but I tried it anyways. Doubling the power to 1300W exceeded xmax by 6mm at 28Hz with a HPF. Boosting 50Hz brought 53Hz up to xmax and exceeded it by 7mm. My question was why alter the flat curve just to boost one spot and give it a hump there? It's not going to raise my total output any, so why not just boost every frequency by turning the subs up?

Here is a max SPL test. The amp clipped during the last part of the sweep on the top line, which should be about 650W, 150W more than the drivers are rated for.



Also, running 650W, winisd say I need a 30Hz high pass filter to avoid hitting xmax. At 450W, like Unicron, it was still ~25Hz I think, so I don't understand how he is getting big output at 10Hz without destroying the drivers by going way beyond xmax (7mm, 50%).

Living room: Definitive BP2000TL, CLR3000, BPVX, Quad SI 18" subs
Bedroom: Definitive BP30, CLR2000 Also have had: BP7000SC, BP8B, BP10B, BPX, Dayton 15" HF subs, Rythmik F15
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post #7 of 125 Old 04-04-2013, 05:28 PM
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Well, Dayton did just come out with the new Ultimax line of subs. The UM15-22. HUGE Xmax at 19mm That should get you more output.

http://www.daytonaudio.com/index.php/loudspeaker-components/loudspeaker-drivers-by-series/ultimax-series/dayton-audio-um15-22-15-ultimax-dvc-subwoofer-2-ohm-per-coil.html
http://www.parts-express.com/pe/showdetl.cfm?partnumber=295-514


They model well in that a 4.7 cu ft sealed box too.


If you lived closer, I would buy your 15" HF's from you as I'm looking to buy one or two.

As others have stated, your current setup has a fantastically flat curve, especially for being at your seating position. Many would be in envy for a curve like that (myself included)

Dan
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post #8 of 125 Old 04-04-2013, 05:38 PM
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Quote:
Originally Posted by bradthebold88 View Post

I Excursion difference wasn't really what I was asking about boosting 50Hz, but I tried it anyways. Doubling the power to 1300W exceeded xmax by 6mm at 28Hz with a HPF. Boosting 50Hz brought 53Hz up to xmax and exceeded it by 7mm. My question was why alter the flat curve just to boost one spot and give it a hump there? It's not going to raise my total output any, so why not just boost every frequency by turning the subs up?

I don't understand how he is getting big output at 10Hz without destroying the drivers by going way beyond xmax (7mm, 50%).

I think the suggestion about the 50hz boost with a Q of 2 was to flatten out your response curve even further. If you look at our middle curve from your first chart, there is a general dip between 18hz to 100hz of about 3-4 dB (assuming your measurements are accurate). Bumping up the 50hz band with w very wide Q of 2 will boost most of that area without a huge increase below 20hz where you are Xmax limited.

Regarding the 10hz output, maybe it's due to room gain. Are the measurements taken in the room, or measured anechoic? (free of reflections)

Dan
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post #9 of 125 Old 04-04-2013, 06:13 PM - Thread Starter
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Originally Posted by stereomandan View Post

Well, Dayton did just come out with the new Ultimax line of subs. The UM15-22. HUGE Xmax at 19mm That should get you more output.

http://www.daytonaudio.com/index.php/loudspeaker-components/loudspeaker-drivers-by-series/ultimax-series/dayton-audio-um15-22-15-ultimax-dvc-subwoofer-2-ohm-per-coil.html
http://www.parts-express.com/pe/showdetl.cfm?partnumber=295-514


They model well in that a 4.7 cu ft sealed box too.


If you lived closer, I would buy your 15" HF's from you as I'm looking to buy one or two.

As others have stated, your current setup has a fantastically flat curve, especially for being at your seating position. Many would be in envy for a curve like that (myself included)

Dan

I have looked at the ultimax, but it seems kind of disappointing. In the same size box with the same power, it doesn't output as much as an HF. At 850W (max 2ohm output of the EP4000, though I don't even think I could wire my setup to 2ohm stereo) the Ultimax is only 1dB louder, and that would max out the amp. I could run 4 HF's off the amp and get more output. Excursion limits weren't much different either. Without a HPF at 650W for the HF's and 850W for the Ultimax, the HF's hit xmax at 40Hz and the Ultimax hit it at 35Hz.

As for the 50Hz boost, 6dB is a lot. It just made a big hump over a 20-30Hz range. It seemed to make the curve worse.

From Unicron-wmd: "I run 8 HFs in my theater with just a little over 400watts each driver in "small" 4.2cuft cabs and they sound great and very clean. I have 1" foam on all interior walls and 5lbs of polyfil per driver. They are amp limited which also helps keep everything clean and safe. At the seats, I can hit 118db at 10hz and 122-124db with movie content before the amps start clipping."

His smaller boxes help a little, but at 10Hz, there is enough amp to go 5mm past xmax according to WinISD if I'm using it correctly. And it goes up to 7mm (50%) past it at 5Hz.

Living room: Definitive BP2000TL, CLR3000, BPVX, Quad SI 18" subs
Bedroom: Definitive BP30, CLR2000 Also have had: BP7000SC, BP8B, BP10B, BPX, Dayton 15" HF subs, Rythmik F15
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post #10 of 125 Old 04-04-2013, 08:57 PM
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I have looked at the ultimax, but it seems kind of disappointing. In the same size box with the same power, it doesn't output as much as an HF. At 850W (max 2ohm output of the EP4000, though I don't even think I could wire my setup to 2ohm stereo) the Ultimax is only 1dB louder, and that would max out the amp. I could run 4 HF's off the amp and get more output. Excursion limits weren't much different either. Without a HPF at 650W for the HF's and 850W for the Ultimax, the HF's hit xmax at 40Hz and the Ultimax hit it at 35Hz.

As for the 50Hz boost, 6dB is a lot. It just made a big hump over a 20-30Hz range. It seemed to make the curve worse.

From Unicron-wmd: "I run 8 HFs in my theater with just a little over 400watts each driver in "small" 4.2cuft cabs and they sound great and very clean. I have 1" foam on all interior walls and 5lbs of polyfil per driver. They are amp limited which also helps keep everything clean and safe. At the seats, I can hit 118db at 10hz and 122-124db with movie content before the amps start clipping."

His smaller boxes help a little, but at 10Hz, there is enough amp to go 5mm past xmax according to WinISD if I'm using it correctly. And it goes up to 7mm (50%) past it at 5Hz.

Ah, makes sense. I didn't realize that you were amp limited. Missed that part. Yeah, the HF15 and the UM15 model very close, with the UM having more excursion potential if you have the power available to drive it.

You must drive everyone else nuts in your apartment complex with the amount of low frequency output that you are generating already! smile.gif

Dan
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post #11 of 125 Old 04-04-2013, 10:50 PM - Thread Starter
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Originally Posted by stereomandan View Post

Ah, makes sense. I didn't realize that you were amp limited. Missed that part. Yeah, the HF15 and the UM15 model very close, with the UM having more excursion potential if you have the power available to drive it.

You must drive everyone else nuts in your apartment complex with the amount of low frequency output that you are generating already! smile.gif

Dan

Is that amp limited? Running two, I get 150W more than the HF's are rated for. I would be a little limited running 4 HF's at 425W (75 less than rating), but with 2 amps I could power the Ultimax's with 850W stereo or 2000W bridged to each pair, both over what the driver is rated for. With 1 amp, both different subs would get the same power, so the HF's would be louder. If I get two amps for the Ultimax's, then 2000W per pair would be 3 - 3 1/2dB louder.

With 425W, the HF's hit xmax at 34Hz. With 1000W, the Ultimax's hit xmax at 38Hz. Even at its rated 800W, it hits xmax at 34Hz, so despite it's larger xmax, it has excursion problems at the same point. This is something I don't understand, that can't be right. Would I really need to run 25-30Hz high pass filters to avoid exceeding xmax? Is it ok to exceed xmax by 50%? Otherwise I don't know how anyone can <20Hz output without damaging the driver or running a HPF.

Another thing I just thought of, I may be apartment limited to one amp. There is pretty much no way to plug the amps into separate power lines. 4kW from 2 bridged amps would be about 33amps (I think) over a 15amp line seems like it might cause issues.

Living room: Definitive BP2000TL, CLR3000, BPVX, Quad SI 18" subs
Bedroom: Definitive BP30, CLR2000 Also have had: BP7000SC, BP8B, BP10B, BPX, Dayton 15" HF subs, Rythmik F15
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post #12 of 125 Old 04-05-2013, 05:00 AM
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I didn't look up the specs of your amp. I looked it up. Yeah, it has plenty of power available.

What do you use for your xmax? It looks like 50% of xmax is where you feel comfortable based on post #6, so you used 7mm for the 15"HF and 9.5mm for the Ultimax? These subs may not be 100% linear all the way out to xmax, but they are able to do it according to the specs. (14mm one way for the HF and 19mm one way for the UM)

I'll do some modeling again with the two subs, as they are pretty much what I'm deciding between myself right now.


Dan
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post #13 of 125 Old 04-05-2013, 07:13 AM - Thread Starter
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Quote:
Originally Posted by stereomandan View Post

I didn't look up the specs of your amp. I looked it up. Yeah, it has plenty of power available.

What do you use for your xmax? It looks like 50% of xmax is where you feel comfortable based on post #6, so you used 7mm for the 15"HF and 9.5mm for the Ultimax? These subs may not be 100% linear all the way out to xmax, but they are able to do it according to the specs. (14mm one way for the HF and 19mm one way for the UM)

I'll do some modeling again with the two subs, as they are pretty much what I'm deciding between myself right now.


Dan

I used 14mm for the HF and 19mm for the UM when modeling. With their rated power, they both hit xmax around 35Hz. At 10Hz they are 5-7mm past xmax, which is about 50% more for the HF is what I was trying to say.

Living room: Definitive BP2000TL, CLR3000, BPVX, Quad SI 18" subs
Bedroom: Definitive BP30, CLR2000 Also have had: BP7000SC, BP8B, BP10B, BPX, Dayton 15" HF subs, Rythmik F15
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post #14 of 125 Old 04-05-2013, 08:01 AM
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Yeah, so I modeled the two subs, and agree with what you found. Basically, they model pretty similar in a 4.7 cu ft box, but the UM is capable of roughly 3 dB more output before Xmax.

I tend to model a little differently for a sealed enclosure. I look at the lowest frequency that I expect the sub to play, say 20hz, and determine the power it takes to hit Xmax at that frequency. What I came up with for these two subs in your 4.7 cu ft sealed enclosure (with no polyfill) is about 210W 14mm Xmax @ 20hz for the HF (101.5 dB), and 430W at 19mm Xmax @ 20hz for the UM. (104 dB).

The Qts of both are pretty similar in your enclosure, (0.75-0.78 with no polyfill, or 0.64 to 0.67 with) so the response curve is nearly identical, but the UM outputs more if you have the power available to drive it. So if starting over again, the UM might be a good choice, but it’s not worth it at this point to switch subs.

Now, if you build large ported enclosures with your HF’s you can get MUCH more output. ( I’m assuming your output now is Xmax limited) Say, a 6 cu ft enclosure (unfilled) with a single 6” port (dual flared) tuned to 17 hz. (23.5” long port not including the flares) You hit 14mm Xmax at 25hz at 240W, but you have a dead flat response curve down to 20Hz due to the port contribution, with a –3dB point at 16Hz. Your output jumps to 110 at 20hz versus 101.5 with your current sealed box.

I prefer sealed subs, but if you are looking for more output, that is how you can get it.

Dan
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I have some questions for you guys Can someone model both the HF15 and the UM15 in some large enclosures and see which one has the most extension and output? I am looking into buying some more subs for my other room,
and can not decide between the HF15 and the UM15. I have absolutely zero WAF nor do I have any size or space restrictions. .I can possibly do up to 20 cubic feet for each enclosure, (so yea, no size or space restrictions!). With that
being said, what ever I end up going with will be powered by a single EP4000. What do you guys think of the UM15 vs the HF15 if you were to only use 1 EP4k and have no size/space restrictions?
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I have some questions for you guys Can someone model both the HF15 and the UM15 in some large enclosures and see which one has the most extension and output? I am looking into buying some more subs for my other room,
and can not decide between the HF15 and the UM15. I have absolutely zero WAF nor do I have any size or space restrictions. .I can possibly do up to 20 cubic feet for each enclosure, (so yea, no size or space restrictions!). With that
being said, what ever I end up going with will be powered by a single EP4000. What do you guys think of the UM15 vs the HF15 if you were to only use 1 EP4k and have no size/space restrictions?

In the same size box with the same power, the HF is 0.5dB louder. At 650W (EP4000 4ohm stereo output) in 4.7cf boxes, the HF hits xmax around 40Hz and the UM hits it around 30Hz. At 850W (2ohm stereo output), the UM hits xmax around 35Hz and is 0.5-1dB louder than the HFs. If you run the UM on 4ohm bridged with 1000W per sub, it would hit xmax at 38Hz and be 1.5dB louder than the HFs. Running 4 HFs at 2ohm stereo with 425W/each would get you 3dB more output than 2ohm stereo pair of UMs. 4 UMs with the same power would be 0.5dB quieter but hit xmax a little lower. With 425W, the HF hits xmax at 34Hz. So it seems like the best setup would be 4 HFs. They have more output than 2 or 4 UMs and only hit xmax a few Hz higher. If you only wanted 2 subs, the UM would only be 1dB louder. Except I think there is only 2+2 DVC UM's, so you couldn't wire 2 of them to do 2ohm stereo anyways I don't think.

Both appear to have xmax issues. In my max SPL test above, the graphs don't appear to have issues, but winISD says that I would have exceeded xmax by 5.5mm at 30Hz. I didn't hear any bad sounds either. I'm still hoping someone can explain if there is some protective feature of a sealed box that winISD isn't accounting for that could explain this and how Unicron can clip at 10Hz well over xmax without damaging the subs.

If the SI 18 can handle 1000W (rated for 600W), it just barely exceeds xmax at low single digit Hz and would be 4.5-5dB louder than a 650W HF. You could run 4 off of 2 amps at 4ohm bridged and get significantly more output and extension. The subs are about the same price too. A pair at 850W 2ohm stereo would be 3.5dB louder than a pair of UMs with the same power and 4dB louder than 650W HFs with no xmax issues. More drivers is better though, so off 1 amp, 4 HFs have 2-4dB more upper output and a lot more lower output/extension.

Also, making the boxes bigger just causes more xmax issues for the Daytons. You could make the SI bigger though without issue.

Living room: Definitive BP2000TL, CLR3000, BPVX, Quad SI 18" subs
Bedroom: Definitive BP30, CLR2000 Also have had: BP7000SC, BP8B, BP10B, BPX, Dayton 15" HF subs, Rythmik F15
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post #17 of 125 Old 04-06-2013, 10:21 AM - Thread Starter
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Quote:
Originally Posted by stereomandan View Post

Yeah, so I modeled the two subs, and agree with what you found. Basically, they model pretty similar in a 4.7 cu ft box, but the UM is capable of roughly 3 dB more output before Xmax.

I tend to model a little differently for a sealed enclosure. I look at the lowest frequency that I expect the sub to play, say 20hz, and determine the power it takes to hit Xmax at that frequency. What I came up with for these two subs in your 4.7 cu ft sealed enclosure (with no polyfill) is about 210W 14mm Xmax @ 20hz for the HF (101.5 dB), and 430W at 19mm Xmax @ 20hz for the UM. (104 dB).

The Qts of both are pretty similar in your enclosure, (0.75-0.78 with no polyfill, or 0.64 to 0.67 with) so the response curve is nearly identical, but the UM outputs more if you have the power available to drive it. So if starting over again, the UM might be a good choice, but it’s not worth it at this point to switch subs.

Now, if you build large ported enclosures with your HF’s you can get MUCH more output. ( I’m assuming your output now is Xmax limited) Say, a 6 cu ft enclosure (unfilled) with a single 6” port (dual flared) tuned to 17 hz. (23.5” long port not including the flares) You hit 14mm Xmax at 25hz at 240W, but you have a dead flat response curve down to 20Hz due to the port contribution, with a –3dB point at 16Hz. Your output jumps to 110 at 20hz versus 101.5 with your current sealed box.

I prefer sealed subs, but if you are looking for more output, that is how you can get it.

Dan

That makes sense in modeling, but I've been running 650W with a 19Hz high pass filter and have never heard the subs distort, clank, or make any bad sounds. During the SPL test above, WinISD said I should have exceeded xmax by ~5mm at 30Hz, but there didn't seem to be any issue with the subs or the graph to indicate anything was wrong. There has to be something that WinISD isn't accounting for that would allow this and let Unicron clip the amp at 10Hz well over xmax without damaging his subs.

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In the same size box with the same power, the HF is 0.5dB louder. At 650W (EP4000 4ohm stereo output) in 4.7cf boxes, the HF hits xmax around 40Hz and the UM hits it around 30Hz. At 850W (2ohm stereo output), the UM hits xmax around 35Hz and is 0.5-1dB louder than the HFs. If you run the UM on 4ohm bridged with 1000W per sub, it would hit xmax at 38Hz and be 1.5dB louder than the HFs. Running 4 HFs at 2ohm stereo with 425W/each would get you 3dB more output than 2ohm stereo pair of UMs. 4 UMs with the same power would be 0.5dB quieter but hit xmax a little lower. With 425W, the HF hits xmax at 34Hz. So it seems like the best setup would be 4 HFs. They have more output than 2 or 4 UMs and only hit xmax a few Hz higher. If you only wanted 2 subs, the UM would only be 1dB louder. Except I think there is only 2+2 DVC UM's, so you couldn't wire 2 of them to do 2ohm stereo anyways I don't think.

Both appear to have xmax issues. In my max SPL test above, the graphs don't appear to have issues, but winISD says that I would have exceeded xmax by 5.5mm at 30Hz. I didn't hear any bad sounds either. I'm still hoping someone can explain if there is some protective feature of a sealed box that winISD isn't accounting for that could explain this and how Unicron can clip at 10Hz well over xmax without damaging the subs.

If the SI 18 can handle 1000W (rated for 600W), it just barely exceeds xmax at low single digit Hz and would be 4.5-5dB louder than a 650W HF. You could run 4 off of 2 amps at 4ohm bridged and get significantly more output and extension. The subs are about the same price too. A pair at 850W 2ohm stereo would be 3.5dB louder than a pair of UMs with the same power and 4dB louder than 650W HFs with no xmax issues. More drivers is better though, so off 1 amp, 4 HFs have 2-4dB more upper output and a lot more lower output/extension.

Also, making the boxes bigger just causes more xmax issues for the Daytons. You could make the SI bigger though without issue.


If these subs are hitting xmax at 30hz+ then how do so many of these people around this forum claim to get their HO15 or UM15's flat down to like...16hz or 17hz? IF these subs will only go down to 30hz or somewhere in the high 20's then wouldn't they be a poor choice for home theater?
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If these subs are hitting xmax at 30hz+ then how do so many of these people around this forum claim to get their HO15 or UM15's flat down to like...16hz or 17hz? IF these subs will only go down to 30hz or somewhere in the high 20's then wouldn't they be a poor choice for home theater?

That is exactly what I'm wondering. Either you greatly limit the power (210W) like Dan said, which would still exceed xmax below 20Hz, or run a high HPF. Or there's something I don't understand because I've been running 650W with a 19Hz HPF and Unicron runs 425W with no filter with no noticeable problems.

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If these subs are hitting xmax at 30hz+ then how do so many of these people around this forum claim to get their HO15 or UM15's flat down to like...16hz or 17hz? IF these subs will only go down to 30hz or somewhere in the high 20's then wouldn't they be a poor choice for home theater?

Here is a model of the UM at 10ftcu 800watts 16hz tune with high pass filter at 16hz, it exceeds xmax by 5mm at about 11hz and 4mm at 25hz. Should work great for HT, could feed it less power if you are worried about the excursion.


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I'm not questioning you ,but how do you know you are running 650W? Do you have a watt meter, or is there a readout on your amp?

Dan
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I'm not questioning you ,but how do you know you are running 650W? Do you have a watt meter, or is there a readout on your amp?

Dan

That's just a guess. I would imagine it's close to that though. The amp was measured to output 625-650W at 4ohm stereo in the amp measurement thread, so when it's clipping, I am guessing it is close to that measurement.

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All pictures are with 4.7cf boxes x 2. Here are HF excursions with 2, 4, and 8ohm output of an EP4000 amp. Even with less than half their rated power, the exceed xmax down low a bit. Purple is with a 19Hz HPF I use. It would take a 29Hz HPF to limit xmax at 1300W, 22Hz at 850W.



Running at 225W/ea loses >4dB output compared to 650W/ea. Even with a HPF 10Hz below what it should be, there is significant low frequency loss due to it.



Even at 850W (250W more than rated), the SI 18 has no excursion issues.



Green is 1 SI, Red is 2 compared to 2 HFs. 1 SI has 2dB+ more output than 2 HFs limited in power to limit excursion. Looks like it would be similar to 425W going to a pair of HFs, though they would need a 22Hz HPF. 2 SIs have 8dB more output than excursion power limited HFs and significantly more than 2 overpowered (1300W) HFs witha too low HPF.



When I asked about subs in the first place, I was recommended 4 HFs with a EP4000. I would have to run each pair at 8ohm stereo to not get excursion issues though, which seems like a waste of the amp. Why would anyone use these subs if they can only take 200W before exceeding xmax? It doesn't really matter if they can go low if they have low output too. A similar sub that can take 4 times the power would a 6dB advantage so it would probably beat it low down anyways by brute force.

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I've had similar issues modeling the Ultimax's cone excursion. I eel like something has to be going wrong. I was getting that if I drove the Ultimax with 800 watts in a 4 foot sealed enclosure, I'd be reaching Xmax at around 33 Hz. That can't be right..... right?
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I've had similar issues modeling the Ultimax's cone excursion. I eel like something has to be going wrong. I was getting that if I drove the Ultimax with 800 watts in a 4 foot sealed enclosure, I'd be reaching Xmax at around 33 Hz. That can't be right..... right?

That seems to be right based off the modeling. Unless you use a small box and half or less of its rated power, you will go past xmax.

I tested different high pass filters to see the result. Green is no filter, red is a 22Hz filter for 425W, and blue is 30Hz for 650W. Gold is an 18Hz filter that would go 1.5mm over xmax for 425W. That one actually looks ok for having to use a filter, but I would still have to give up a lot of extension. This is with Audyssey run with a 19Hz HPF though, so it might be a little different than if Audyssey was run with each one.

I would like to know what people with these subs actually do because I ran a 19Hz filter for a year seemingly without issue, and that should go 5mm over xmax. That would be the same risk as running 425W with a 8Hz HPF. If I ran 4 HFs at 425W with a 8Hz HPF, that would gain me 4dB output up higher and 6.5dB at 20Hz compared to 650W with a 19Hz HPF. Or a 15Hz HPF would limit it to just under 3mm over xmax. How much leeway is there with xmax?

With a 15Hz HPF, 4HFs would be 0.5-2dB louder than a pair of SI 18s with the same power from 15Hz up, though it would take twice as many drivers and boxes. Assuming sound quality would be the same (?), I would probably go with 4 SI 18s, but that would require another amp and a potential max ~30amp load wouldn't work with the 15amp line to my living room. Or I could get most of the performance with 2 SI 18s now and build 2 more when I get a house or somewhere that would have adequate power or that I could upgrade.


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I feel like we either have a modeling problem or the Xmax is wrong. I was going to order these but now I'm a little hesitant. But I dunno what else would model better for 170. I wanna order soon though since I only have access to a cnc for another month.
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I feel like we either have a modeling problem or the Xmax is wrong. I was going to order these but now I'm a little hesitant. But I dunno what else would model better for 170. I wanna order soon though since I only have access to a cnc for another month.

Are we talking about the RSS390HF 15 or the UM 15? Here is a model of the ultimax @800W sealed box, green is in a 4cuft box and red is in 3.1 cuft box(dayton recommended size). No issues with the 3.1 size until about 10hz.



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Are we talking about the RSS390HF 15 or the UM 15? Here is a model of the ultimax @800W sealed box, green is in a 4cuft box and red is in 3.1 cuft box(dayton recommended size). No issues with the 3.1 size until about 10hz.

The um 15, your graph shows the um15,hitting past Xmax at 30 hz? Not 10,unless I don't understand the graph.
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WinISD says a 0.707Q requires a 6.6cf box. It recommends a larger box than the HF by a cubic foot. In that box, it exceeds xmax at 43Hz. At 10Hz, excursion is 32mm. A 3cf box has a Q of 0.885.

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I am a noob as far as building subs just like to mess around with WinISD so it is very possible that I messed up the T/S parameters somehow. Besides that though, other daytons that have been measured show useable throw over rated Xmax. See http://www.data-bass.com/data?page=driver&id=48

If it was me, and wish it was, I would go for it but that's just me. Would be nice if some of the more experienced guys on here chimed in. hint hint biggrin.gif


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