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18" build (Arande)

27K views 143 replies 17 participants last post by  brandonnash 
#1 ·
I decided if I don't do anything, I won't ever get a sub built.


So I've decided that I will order a driver within the next week or two.

History: Within the past years I've had different designs, but I never managed to get the money together. One time it was 8 Aurasound NS18s when I thought I was going to be able to do that. Of course, I never got the money together. It was once 4 Fi 18s (one per corner), before the NS18 thought. Now I'm back to a single 18" driver.

Basic idea: My current plan is to use a single Fi Q18 (maybe with a small change, depends on the e-mail I get back) in a large enclosure with a tuning around 13-15 hertz.


The source of power will start out as my old receiver (probably 200-250 watts) until I can afford the next part. If I decide I want more even response with a bit more SPL (or less distortion), I will build a duplicate of the original enclosure and use more channels to get 400-500 watts and place them to get best response. If I decide I just want it louder, I will buy an amp to bring it up to about 2kW. Then after that, I plan to bring in the one I didn't do first (so if I decided on the amp, I'd build the second sub).

The Area: The full area I will consider this to be filling is about 8000 cubic feet, but the listening area only takes up a third of that. The current speakers all have 12" woofers and I am currently planning to do a crossover around 60hz. I am using a Pioneer Elite VSX91-TXH for the receiver (which was bought with the store credit of a blown sub I returned).


It's better to have a single sub on limited power than no sub at all.


Tastes/Material: Usually I'm listening to music, but a movie tends to creep in every other day. The music is usually metal, such as Metallica (and KoRn), but I listen to a lot of different styles.

Current experience: I am unimpressed by the low end on my system, and music sounds thin. In movies, the explosions are there, and I can feel gunshots etc.. but it's obviously missing the sub 30-35hz content and sounds thin.



...


Any suggestions are welcome on these decided things, although I may or may not take them to heart.



The box plan is 2x3x5 (driver on 2x5 side, sub standing on 2x3 side, port likely on top). The current plan is to be able to hook the driver up in different coil configurations on the back of the cabinet, to make things easier.



Current undecided/unknown things: Cloth for cover, build difficulty, exact EQ, safety of pictures on wall.


Thanks!


EDIT: This thread contains the most recent information on page three, a jump of over a year.
 
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#103 ·
Hey thanks for joining in to help.


I am sitting in a partial null, I think, which does not help.



I had a Paradigm UltraCube 10. It was kinda okay, but it was so quiet. I blew it pretty fast.


I can say that this amp is a good improvement, and I still am not done calibrating.


Also, pretty much any speaker that had decent bass in other houses lost it when I brought it in this room. It may be lossy to bass.


Once I am done calibrating, I'll see where I am.
 
#105 ·
I have an idea. This will rule out that anything is wrong with the sub. Take it in a different room and play it. It does sound like it may be your room doing that.
 
#106 ·

Quote:
Originally Posted by penngray /forum/post/18690572


What SPL can you get out of that sub @ 1m ?


Put ear plugs in and play a 20Hz and then 30Hz tones. Find out what your max SPL is.

I am worried about damaging the driver?





And brandonnash, I would try that, but there is no space for it (to even try) in the rest of the house. It would take a lot of work to make space.
 
#107 ·
And by a method of 2 sec test bursts, I saw a reading no higher than 110dB. I did not see the clip lights either, but I'm sure I was right up there. The sub didn't sound very good . . .


The output hit 100dB at my listening position max.



It bottoms sometimes, and I do not see any clip lights, and I'm sure I'm not passing 500w.
 
#110 ·
Yes. I could give it several volts if needed. I could easily get the clip lights to come on if I wanted to.


I look at the driver and if it's not at its limits, then I don't know what being 'at the limit' is.


The sensitivity seems to come out about 80dB (77-84 depending on frequency) and it's just not very loud. The sensitivity has to be going somewhere.
 
#111 ·
I am trying not to give up, but it is hard. I'll have to continue experimenting.


I also am not sure what's missing in the SQ. It seems to be missing punch (even if that punch might be a freq boost somewhere) and depth.



With the results I have been getting thus far, a higher tune or more efficient driver might be better. I can't be sure though, as I have not figured out what the problem is. So for those who recommended a pro driver may have been right. I'll have to watch WOTW to see if it is worth it. It doesn't sound as deep as I would have expected.


. . . not sure what to troubleshoot anymore.
 
#112 ·
If its your room that's causing this problem you can add and add and still probably have a problem. If you take a corvette and add horsepower to it it should go faster, but it will have a limited top speed if its trying to haul 2 tons of concrete behind it.
 
#113 ·

Quote:
Originally Posted by brandonnash /forum/post/18696976


If its your room that's causing this problem you can add and add and still probably have a problem. If you take a corvette and add horsepower to it it should go faster, but it will have a limited top speed if its trying to haul 2 tons of concrete behind it.

Maybe so, and if that's the case, then it's sad that I can't go to any other room.




I tried boosting the signal 18dB (and dropping the receiver's output and lowering the gain knob a bit). No diff really. The driver starting making bad noises at the same SPL (I am right in front of the driver, can barely feel it).


The whole subwoofer visibly shakes a bit with lower freqencies, so maybe it needs a bit of work?



I remember these speakers outside in a pavillion (size of a basketball court) once. There were 2 of them, one on each side widthwise, each with a 12" driver and a horn. There was a QSC amp with 200w/ch at the speaker impedance rating. They were playing a song and turned it up a bit, and I could strongly feel it from the other side of the pavillion.


I understand they were Klipsch pro speakers and probably had high sensitivity.


It's funny because here I am with a large 18" subwoofer on a 2000w amp in a 2500 cubic foot (with a large opening into 8000 cubic feet) room and I have yet to feel it.



I also remember, not far from that same pavillion, a building where they had maybe 12 15" drivers and a few 12s spread across the front of a stage in a very large room (200x80x40 feet, I bet, probably larger).


They played Breathe Into Me by Red and I could easily feel it when it was at normal volume. Then they played this rap song and it was awesomely loud, the bass. I could feel the bass after I left the building, and I could hear the bass long after I stopped being able to see the building.


Then I also remember, in another room, even larger than the first, they have 4 18" subwoofers which can easily be felt as well. It is owned by the same people.



Not only could I feel it in these situations, but it sounded great too, especially 2nd room.



So then I go back to, why can 2 12s on 400w total be felt outside on opposite ends of a pavillion when I cannot feel an 18" in a small room with a 2000w amp backing it?



...


I currently have the subwoofer turned off as it seems to cause "more harm than good."
 
#114 ·
It has to be something wrong with the actual driver or wiring...granted...those experiences above might not be met with this sub...but you should deff be having your world rocked with an 18 and 2000 watts of clean power...have we ruled out wiring and is there any way to replace the driver?
 
#115 ·
I think I will just move the home theater into the closet




Just kiddin'



I am 100% sure about the wiring.

However, the driver - I could replace it if I had to. The problem is where do I get another driver to replace it with?
 
#116 ·
It sounds like the 'experience' or feeling you are looking for isn't what you can generate with the current device you have.


1) The room is lossy, the output from the device is being dissipated in >10,000 cubic feet, and every surface that sympathetically vibrates will be robbing you of output at low frequencies.


2) You checked outside, and noticed that the output scales pretty linear with the input, so it's not the subwoofer driver. It is working as intended, but it's design band of operation is also where your room is the most lossy.


3) Impact, that kick in the chest / punch feeling is much higher in frequency than the subwoofer you built is designed to reproduce. Not that it can't do it, but it will be a lot less efficient than something like a pro sound oriented cabinet.


4) Output @ 40-80 hz is less likely to be absorbed by walls, ceilings, floors etc vibrating because it's generally much higher in frequency than the panel natural frequency ( how well they are made, how tall / long / thick, supports etc )


5) Cancellation between subwoofers and main speakers. Ported speakers have a rapid phase change around tuning. If your main speakers are ported, and the transition to a subwoofer isn't great, you will also loose energy around the upper mid bass. ( not much impact )


Depending on your desired crossover point, tuning point of the main speakers, etc, you may be able to eq the main speakers rolloff to simulate that of a sealed speaker, and achieve an easier transition with less cancellation.


I hope this helps. Can you rent a pro sound subwoofer to try it out to see if it will meet your needs?
 
#117 ·

Quote:
Originally Posted by michael hurd /forum/post/18706000


It sounds like the 'experience' or feeling you are looking for isn't what you can generate with the current device you have.


1) The room is lossy, the output from the device is being dissipated in >10,000 cubic feet, and every surface that sympathetically vibrates will be robbing you of output at low frequencies.


2) You checked outside, and noticed that the output scales pretty linear with the input, so it's not the subwoofer driver. It is working as intended, but it's design band of operation is also where your room is the most lossy.


3) Impact, that kick in the chest / punch feeling is much higher in frequency than the subwoofer you built is designed to reproduce. Not that it can't do it, but it will be a lot less efficient than something like a pro sound oriented cabinet.


4) Output @ 40-80 hz is less likely to be absorbed by walls, ceilings, floors etc vibrating because it's generally much higher in frequency than the panel natural frequency ( how well they are made, how tall / long / thick, supports etc )


5) Cancellation between subwoofers and main speakers. Ported speakers have a rapid phase change around tuning. If your main speakers are ported, and the transition to a subwoofer isn't great, you will also loose energy around the upper mid bass. ( not much impact )


Depending on your desired crossover point, tuning point of the main speakers, etc, you may be able to eq the main speakers rolloff to simulate that of a sealed speaker, and achieve an easier transition with less cancellation.


I hope this helps. Can you rent a pro sound subwoofer to try it out to see if it will meet your needs?

Yes, my thoughts as well.



My mains are tuned 43hz, I have them crossed at 50. The resulting response is flat, but is it possible that a cancellation should still occur and I would lose energy somehow? I doubt it. Bumping the freq response and trying other things does not seem to work.


I've been wanting to try a pro audio sub to see, but it costs too much right now.


I never glued the top cap on the sub, and so it popped off a bit from bass and vibrates loudly. I should probably do something about that.
 
#118 ·
I had a dream.


The subwoofer, I kept banging on it to try to get it to work. By the end of that sequence, The sonotube was all frayed and the legs broken. The driver was on the ground and I was thinking (in the dream) that I should build a sealed box. ... If I'm dreaming about it, it must be pretty bad




Then I moved on to the next dream..
 
#119 ·
you gotta be having some isses with your enclosure design or room, bud. i have two fi ssd18's and even running one of them in a 8 cube box tuned to 20 hertz with about 400 watts was enough to make most people i demoed it for tap out. now im running both on a 5kw amp, and they make my neighbors tap out when i turn it up.
 
#120 ·

Quote:
Originally Posted by arande2 /forum/post/18710378

I never glued the top cap on the sub, and so it popped off a bit from bass and vibrates loudly. I should probably do something about that.

This is not a good sign. Your driver and enclosure must be sealed well (except for the port) or there will be leaks and cancellation of output. I would guess that your enclosure leaves much to be desired and is leaving much of the drivers possible performance unrealized.
 
#122 ·
I decided to try some EQ yesterday along with some subwoofer crossover and level experimenting.


I always had the suspicion that I am looking for more upper frequencies, but I could never get it to work. I now tried it with the new amp and found that a change in crossover from 50hz to 100hz and a level boost of +6 gets me a lot closer to the sound I am looking for.


However, I need to continue to tweak to EQ to get the sound right, especially where there is a 'bass line' that needs to sound even across the scale. I have an idea though, probably not a new one.


I also need to build a second sub to shift the balance to the center.
 
#123 ·
What mains are you using?


Also, going back to your first page you said the sub had "VERY NOTICEABLE mechanical noise". Did you ever figure out why or why it just went away?


I'm no expert by far, but it sounds to me like you may have designed the sub for something that you weren't really looking for. You said you liked the 'punch in the chest' sound you heard from professional subs, but then built something tuned WAY lower. Aren't pro subs tuned much higher, like around 30hz +?



If I were you, I'd go back to the very beginning and remove and recheck the sub driver by itself. I'd then be tempted to build a much smaller enclosure, tune it higher and cross it over higher as well. Your first goal was for a slamming music sub, but I've never heard a great one built that large and tuned that low.


I hope you get it figured out.
 
#124 ·

Quote:
Originally Posted by Erich H /forum/post/18737613


What mains are you using?


Also, going back to your first page you said the sub had "VERY NOTICEABLE mechanical noise". Did you ever figure out why or why it just went away?


I'm no expert by far, but it sounds to me like you may have designed the sub for something that you weren't really looking for. You said you liked the 'punch in the chest' sound you heard from professional subs, but then built something tuned WAY lower. Aren't pro subs tuned much higher, like around 30hz +?



If I were you, I'd go back to the very beginning and remove and recheck the sub driver by itself. I'd then be tempted to build a much smaller enclosure, tune it higher and cross it over higher as well. Your first goal was for a slamming music sub, but I've never heard a great one built that large and tuned that low.


I hope you get it figured out.

Hi Erich H


For what they are, they're not too bad. http://www.amazon.com/KLH-AV5001-Flo.../dp/B000021YTH


Yes, the mechanical noise seems to have gone away. I think the "amp" I was using before had something to do with it.


Indeed. My original idea was that the graphs said 120dB w/1000w input and that would be enough at any frequency. Apparently my enclosure needs help, limiting output, although nothing seems wrong superficially - at least until I crank it. I have grown to especially like the sub-30hz output and it is very nice for a lot of my favorite songs that have good sub-bass along with all the movies (about one a day on this system), so I could not just change the design. Instead, integrating a pro sub or building a second sub would probably do the trick.



Thank you. I will eventually find the answer, I am sure. It is out there. It's either right in front of me (forest for the trees), or it's something I will have to work hard to figure out (needle in the haystack). I doubt it's somewhere in the middle.


Time will tell.
 
#126 ·
I can, but It wouldn't look very good
It's not having enough effect for me to do that, anyway.


I was playing a song (Dancing Days (cover) by Stone Temple Pilots) and I saw the clip lights blinking with each drum kick. I thought it sounded pretty good, but the volume was about half as loud as I would have expected.
 
#127 ·

Quote:
Originally Posted by arande2 /forum/post/18747820


I can, but It wouldn't look very good
It's not having enough effect for me to do that, anyway.


I was playing a song (Dancing Days (cover) by Stone Temple Pilots) and I saw the clip lights blinking with each drum kick. I thought it sounded pretty good, but the volume was about half as loud as I would have expected.

Aren't the PRs in back, anyway? Worth a shot, as it should be reversible.


Anyway, I assume you've tried playing with polarity, phase/delay, crossover points/slopes? Most of the time it's an empirical process, and the best result isn't necessarily what you might think going in.


That 60-130Hz suckout in the sub+main FR you have is really the opposite of what you want for impact. If anything, you'd want a bump up in that region for kick.
 
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