Help with sealed box dimensions (Dual Ultimax 15" build)
Sooo i thought about DIY Subwoofers since my current 15" Jamo THX Sub is not enough anymore.
The current driver of choice would be the Dayton Audio Ultimax 15".
The idea is to build two ~105L (3.7 cft) Boxes, not counting driver-displacement or bracing, powered by an amp with approx. 2x 450-510W@4Ohms (db technologies HPA 1000 / crown XLI 1500).
I want effortless tight bass down to 20hz but with a good amount of punch in the upper regions for Movies/Music/Games at a max volume of around -10db on my AVR in a 25qm² (~269 sqft) Room. My current cut-off frequency for the LFE is 90hz.
The cost of this would be rougly 1000-1100 for both, maybe a bit more. Same as buying two Klipsch R 115SW. I really want to beat those.
The Questions i have:
First of all: do these box dimensions with this speaker paired with the amps make sense? Can it be built smaller and still deliver)
Second: Does it make sense to build this over buying two of the Klipsch R115SW off-the-shelf subs?
I hope you can help me out 🙂 I never built a sub (or speaker) so i don't know every minute detail about building one (have learned much in the past weeks though). I am not clumsy concerning woodwork but i just want to make sure that it makes sense. I don't want to end up with two huge subs with which i'm not really satisfied in the end.
Attached is a simulation in WinISD if that helps:
Sooo i thought about DIY Subwoofers since my current 15" Jamo THX Sub is not enough anymore.
The current driver of choice would be the Dayton Audio Ultimax 15".
The idea is to build two ~105L (3.7 cft) Boxes, not counting driver-displacement or bracing, powered by an amp with approx. 2x 450-510W@4Ohms (db technologies HPA 1000 / crown XLI 1500).
I want effortless tight bass down to 20hz but with a good amount of punch in the upper regions for Movies/Music/Games at a max volume of around -10db on my AVR in a 25qm² (~269 sqft) Room. My current cut-off frequency for the LFE is 90hz.
The cost of this would be rougly 1000-1100 for both, maybe a bit more. Same as buying two Klipsch R 115SW. I really want to beat those.
The Questions i have:
First of all: do these box dimensions with this speaker paired with the amps make sense? Can it be built smaller and still deliver)
Second: Does it make sense to build this over buying two of the Klipsch R115SW off-the-shelf subs?
I hope you can help me out 🙂 I never built a sub (or speaker) so i don't know every minute detail about building one (have learned much in the past weeks though). I am not clumsy concerning woodwork but i just want to make sure that it makes sense. I don't want to end up with two huge subs with which i'm not really satisfied in the end.
Attached is a simulation in WinISD if that helps:
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Hi kite,
The Ultimax 15 is a great subwoofer. I talked two friends into buying them, both are still very happy after about two years in use. One friend got the 3 cuft knockdown enclosure and the Dayton SA1000 subwoofer amp. The other friend built an 11 cuft slot ported enclosure and used a bridged Crown XLS1002.
To answer your first question. Yes. 3.7 cuft sealed should work well with the subwoofer, but I think you need more power, 800-1000 watts. One thing you should consider is you may need to add some bass boost at 20-25hz when using a sealed enclosure. Most proaudio amplifiers have a 1.4 volt input sensitivity and home audio receivers have a .775 volt output, so you will not get the full power out of the amp unless you use a signal booster between the two. Hope this was helpful.
Regards,
Matt
The Ultimax 15 is a great subwoofer. I talked two friends into buying them, both are still very happy after about two years in use. One friend got the 3 cuft knockdown enclosure and the Dayton SA1000 subwoofer amp. The other friend built an 11 cuft slot ported enclosure and used a bridged Crown XLS1002.
To answer your first question. Yes. 3.7 cuft sealed should work well with the subwoofer, but I think you need more power, 800-1000 watts. One thing you should consider is you may need to add some bass boost at 20-25hz when using a sealed enclosure. Most proaudio amplifiers have a 1.4 volt input sensitivity and home audio receivers have a .775 volt output, so you will not get the full power out of the amp unless you use a signal booster between the two. Hope this was helpful.
Regards,
Matt
Aside from many other good reasons Matt has in mind, once you reach low and have a lot of power, a sealed box will protect the driver (and the sound) from flopping around below the range you want.
The bigger a sealed box is the better the sound. Why stuff your woofer into a such a little box?
B.
Or use a 6th order vented alignment that rolls off power below Fb. Keele wrote a nice paper on the subject:
http://www.xlrtechs.com/dbkeele.com/PDF/Keele (1975-07 AES Published) - New Set of VB Alignments.pdf
Not sure as I would apply the term "nice" to one of those AES papers exploring how a manufacturer can take a junk driver and make "a silk purse" out of it. Almost as common as the AES junk-science articles whose only purpose it to find a trick to support a phony patent application. Yes, most other AES published stuff is first-class.
You do remember Keele's two admonitions about out of control rumble motions of the cone? His applications of EQ? Testing in what ElectroVoice thought was a representative room?
Do you really think it is sound advice to OP to create a finicky and complex and trick-tuned confection like a 6th order box that skilled posters elsewhere are fretting over at length?
B.
Matt: I'm not quite sure how to approach buying an amp now, do i have to look out for an amp that also provides .775V output? I remember seeing one or two (crown i believe) but i have yet to find a proper amp. Finding an amp with that much power which is also quiet is not easy it seems 🙂 I found dynacord, db technologies and crown amps which are supposed to be quiet enough, i gotta check about the .775 Volt output though. Thank you for your informational post!
As to why i want to stuff it in a small 3.7L box: I just do not have the space for a larger box, sad as it is 😀
As to why i want to stuff it in a small 3.7L box: I just do not have the space for a larger box, sad as it is 😀
Was it too much coffee this morning or a badly stubbed toe that created your need to rant like that? Wow.
Look, Ben, you mentioned a sealed box can control cone motion below Fb. I simply suggested that you can do this electronically. I don't consider a 6th order vented system, simply a 2nd order HP filter plus a vented box, to be "finicky and complex". It's nothing of the sort. It's not like I am suggesting motional feedback or servo here...
If Mr kite would like to achieve high output 20Hz response for his "Movies/Music/Games" in a 3.7 cubic foot (I believe "L" for liter is a mistake in kite's post above this one) a 6th order system with a port or (better) a PR is one way to do it and protect the cone below tuning. That is the totality of my point and you are welcome to disagree.
"Was it too much coffee this morning or a badly stubbed toe that created your need to rant like that? Wow."
6th order vented subs are the best thing since sliced bread!
A 2 cu ft 2nd order sealed box with an F3 of 30hz can only be 0.18% efficient (84.55dB).
A 2 cu ft 4th order vented box with an F3 of 30hz can only be 0.36% efficient (87.56dB).
A 2 cu ft 6th order vented box with an F3 of 30hz can only be 0.90% efficient (91.54dB).
6th order vented subs are the best thing since sliced bread!
A 2 cu ft 2nd order sealed box with an F3 of 30hz can only be 0.18% efficient (84.55dB).
A 2 cu ft 4th order vented box with an F3 of 30hz can only be 0.36% efficient (87.56dB).
A 2 cu ft 6th order vented box with an F3 of 30hz can only be 0.90% efficient (91.54dB).
The Crown XLS and XLi series amplifiers have selectable input sensitivity of 1.4 or .775 volt. I'm using the XLS 2502 and a minidsp for subwoofer duty in my HT. It works really well for me, but my subwoofers are also wired for a 2 ohm load to each channel. If you decided to buy two Ultimax 15s and wired the coils of each sub in series you would have a 4 ohm load per channel, so you need to find an amp that puts out max power into a 4 ohm load. The XLi 2500 is a good choice and will put out 750 watts at 4 ohms per channel. You might have to buy a minidsp or some sort of EQ to adjust the Bass boost. As for the fan noise in my XLS, I have never heard it and it is in an equipment rack about 4 feet from my seat. Hope this makes sense. I'm all over the place sometimes 😀.
Regards,
Matt
Ah really good to know 🙂 Yes i've been looking at those series of crown amps 🙂 Just grabbed the last two Ultimax 15" i could find in germany haha, guess i'm doing this now 😀 And yes i was planning on a 4 Ohm load 🙂
I'm going to order a miniDSP as well but will try it out with Audyssey and equalizerAPO (on my PC) first i guess 🙂
After some quick uneducated tests in WinISD it seems that a 5db boost will flatten out the response down to around 25hz. Although 5db seems a bit much it shouldn't be a problem with two 15" ultimax o_o
I'm going to order a miniDSP as well but will try it out with Audyssey and equalizerAPO (on my PC) first i guess 🙂
After some quick uneducated tests in WinISD it seems that a 5db boost will flatten out the response down to around 25hz. Although 5db seems a bit much it shouldn't be a problem with two 15" ultimax o_o
About a year ago I built a pair of HT subs using the 15" Ultimax drivers. I put them in 4 cu ft sealed enclosures. I'm driving them with 500W BASH amps.
500W seems plenty. From my modeling in Unibox, these drivers are excursion limited. I don't understand why comments on numerous forums claim to need 800W to 1,000W. I barely have the gain turned up on the amps. My home theater is about 3,000 cu ft.
500W seems plenty. From my modeling in Unibox, these drivers are excursion limited. I don't understand why comments on numerous forums claim to need 800W to 1,000W. I barely have the gain turned up on the amps. My home theater is about 3,000 cu ft.
Yeah thing is.. i reall don't want to kill the driver 😀 If i (and i know, simulation is simulation) play around in WinISD and let's say i add an EQ at around 25hz Q2 and Gain of 5 to flatten out the response, then add a 4th order highpass at 18 or 20 and apply 500W of power then the cone excursion is 6mm over max. If i add 1000W then it goes through the roof. Yes, that's without room gain but i'm thinking:
Whats the most sensible way of doing this.. applying around 750W of power and limit the driver via highpass so you have more power for the higher bass frequencies? Am i overthinking things? I've had dreams about the driver popping out of the case, burning on the ground 😀
Whats the most sensible way of doing this.. applying around 750W of power and limit the driver via highpass so you have more power for the higher bass frequencies? Am i overthinking things? I've had dreams about the driver popping out of the case, burning on the ground 😀
It's my opinion that when it comes to power, it's better to have more than you need, than left with not enough and wanting more. Shaz could be right, you might be totally satisfied with less power. But there are some that are satisfied with a single 10" subwoofer and 100 watts, than there's the crazies 😉 with 8 18"s and 12,000 watts. Besides that the XLi 2500 is only $100 more than the 1500, and you get 600 watts more power. POWER! Sorry that was my best Jeremy Clarkson impression. Anyways, if you get an amp with the gain knobs on the face plate it's very easy to adjust them as needed. I set my gains differently for movies than I set them for music, usually 3 or 4 clicks more for music.
Regards,
Matt
Regards,
Matt
POWER AND SPEED! Hah, love this show 😉 Yes you're right. I'm looking at the 1500 and 2500 right now haha. Its a little bit more over here (345€ vs 500€) but yeah i get what you mean 😉 And it was stupid of me to "simulate" like that, of course you don't have to crank it up all the way if you don't want to.
But basically 2x750/4 is plenty? I don't know why i'm afraid of so much POWER 😉 I think i'm under the (stupid?) impression, that the subs will die if Audyssey runs a calibration on reference level (which is not the volume i'm normally listening to, more like -10 max in my room) without a miniDSP in between. Still going to order one at a later date since i wanted to build the subs and try it out with using my older yamaha stereo amp for the subs first. With a whopping 100W per channel.
Also: 8 18" and 12.000 Watts. The electricity in this house will kill itself if i ever would switch on something like this 😀 But wow haha
But basically 2x750/4 is plenty? I don't know why i'm afraid of so much POWER 😉 I think i'm under the (stupid?) impression, that the subs will die if Audyssey runs a calibration on reference level (which is not the volume i'm normally listening to, more like -10 max in my room) without a miniDSP in between. Still going to order one at a later date since i wanted to build the subs and try it out with using my older yamaha stereo amp for the subs first. With a whopping 100W per channel.
Also: 8 18" and 12.000 Watts. The electricity in this house will kill itself if i ever would switch on something like this 😀 But wow haha
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