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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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#3 ·
I'm trying to stay a bit open-minded still on possibilities..


What about transmission lines specifically? Anyone tried them with large drivers?
 
#4 ·

Quote:
Originally Posted by arande2 /forum/post/17613003


I'm trying to stay a bit open-minded still on possibilities..


What about transmission lines specifically? Anyone tried them with large drivers?

To get the kind of "tuning" you want with a TL would mean a HUGE box. A lot larger than what you are wanting. The graph that you posted looks like a good honest goal. I was the same way you were for about a month not having a proper amp for the sub. I ran it from both channels of an old pioneer 5.1 receiver in stereo. Be sure to use "direct mode" if you use the old receiver. If you don't you'll have some unwanted EQ added that can mess with the sound of the sub.
 
#5 ·
Thanks for the support, and I'm guessing it worked OK for the time-being.


As for the sub, I've decided to go Sono, and the same basic design still applies.


Unless someone convinces me otherwise, that is the direction I am headed.



Kinda funny going from no sub to a large 18" EBS Sonosub, and probably a second in the future.
 
#6 ·
It did work for the short time I used it, but with such little power the receiver that I was using as an amp would clip and shut off. This would happen obviously in a big scene during a movie and would really ruin the moment. It happened the first time I watched The Dark Knight a couple of times.
 
#7 ·
I had a "650-watt RMS" 10"er at one point, and it didn't seem to do much at all. I blew it quickly. The dB meter read 100dB at higher freqs, and 90dB at lower freqs at max output (down to 28hz), less than 1M away. It didn't do much below 28hz. It sounded okay. Piece of crap for $1000.


I expect this to be quite an improvement, even at 200w input.



Also, the 2Pi space F3 with my current design is 13hz, likely a bit overpowering in my room. A change in tuning down to 13.3hz would bring F3 to 21hz and F6 to 11.3hz. Any lower and I have to switch to 8" port, a choice I am not willing to make.
 
#8 ·
Your second scenario looks better. I would advise an 8" port though. Check your port air velocity with a 6" port and my guess with that low of a tune it would be pretty high. An 8" port would help that out but may cause the port to be too long making some unwanted resonances. You could always go bigger on the enclosure and that may help.


What's the t/s specs for the driver you are using?
 
#9 ·
Fi Q18


Qms, 5.73; Qes 0.63; Qts 0.567

Vas 268 l; fs 23.87hz

RE 2.8ohm; BL 15.1

Le: ~1.5mH

Sd: 1210cm^2


27mm xmax


I model it at 26.13 cubic feet with a single 10" non-flared port tuned to 13.84hz (exactly 3 feet long, and sonotube exactly 6 feet long). The Qa is set to 20 to take into account some absorption of the damping material.
 
#10 ·
I've ordered the driver to set this in stone



I don't plan on having a "bottom plate" below the driver, but instead sitting the sub directly on the legs/feet.


I can cut 4 ~30" circles out of a sheet of 8'x4' MDF, right? I can just alternate them to get it to fit them all.



The current idea is to make sure I know what I'm doing now
Lots of reading ahead of me..
 
#11 ·
:-( since it has only been one day, maybe you can call and cancel. that is not the driver you need.


you need a driver with high efficiency. 21lw1400 is a good one.


there is a build around here, i forget where, comparing the 21lw1400 ported to an svs ultra. 21lw1400 won in attack.


metallica is on of my favorites.


here are some plots of spectral content of their songs:


whiskey in the jar



king nothing



enter sandman



very little relative under 40hz, yet the drive that you purchased is a sub 40hz king kong.


i'd rethink things in terms of a jbl 2242 or at a miminum 18sounds 18lw1400.


...or a horn sub.


just don't want to see you end up disappointed man. we are one in the same.


edit: green is peak spl, red is average spl.


 
#12 ·
You said that you are mostly a music guy (metal) and movies are much less. You have a limited budget right now and limited power. You want as much efficiency as possible, so I think LTD02 is on the better track. Use a big pro woofer like the 21LW1400 or a B&C TBX100 18 and port that dude to about 25-30hz. Goa head and model it versus the Fi Q on 250w.


Another option may be the Bill Fitzmaurice THT horn using the Dayton 15 DVC that everyone is high on right now (apparently me too now
). It gets down close to 20hz and should be very efficient and have a lot of output and is also very affordable to build. The enclosure will be more difficult but the plans are detailed and you could pay someone to help construct the enclosure with saved money.
 
#13 ·
I am currently at school, so I cannot model it, but here are my thoughts:


I listen to a lot of music like Pirates of the Caribbean, NIN, and other stuff as well that has
 
#14 ·
I have the driver.
It arrived today.


Of course I initially hooked it up with the coils out-of-phase. Trying to test the driver obviously caused the amp to shut down due to lack of excursion. I was like "What?"


Then, of course... I fixed the wiring. Testing reveals that the amp doesn't like more than 80w and shuts down at any higher of a level.


Of course there won't be much output without an enclosure, but the amp barely moves the cone on Bass, I Love You.
Definitely going to be quite a difference between 80w (
) and 1800w (
).


I noticed the basket has enough spots for a quad coil. I also noticed the suspension is much stiffer than I've seen before. Another thing I noticed is that it's lighter than I expected, and also a little smaller.


Question:


How much mechanical noise should the driver have? I can hear the noise easily with sine waves, but not music.


Mounting? I don't see how it's supposed to be mounted. The holes don't go through?



Thanks. It looks like it'll do what I am planning on. It already rattles the floor pretty badly with a few mm excursion
 
#15 ·
As of now, I have obtained the Sonotube, one half for now and one half for possibly later (as I bought a full 12 1/4 section).


I haven't seen the camera and don't have access to it right now, but I know pictures would be nice, even if it is an 'old' thing (Sonotube), and not all the rage now (THT)



I figured out mounting, luckily. The holes just don't go all the way through since the rubber was attached without any pre-drilling. It makes sense now. I just make the holes myself, as the holes ARE in the frame itself.
 
#16 ·

Quote:
Originally Posted by arande2 /forum/post/17727697


Question:


How much mechanical noise should the driver have? I can hear the noise easily with sine waves, but not music.

I think that your little amp is clipping, that's why you hear noise. Amp clipping on sine waves sounds a lot like mechanical noise.
 
#17 ·

Quote:
Originally Posted by Th3_uN1Qu3 /forum/post/17743508


I think that your little amp is clipping, that's why you hear noise. Amp clipping on sine waves sounds a lot like mechanical noise.


I don't know.. If I turn it down really low so that I can barely hear it, I can hear the noise if I put my ear close. I am going to do some testing to find out
 
#18 ·
A little mechanical noise is normal for every speaker. If it's not audible at listening position i wouldn't worry.
 
#19 ·
Well luckily after a while the VERY NOTICEABLE everywhere mechanical noise seems to have disappeared.



Hopefully it stays that way. Now I can't really hear anything except harmonics with my ear by the cone. They're VERY faint as well, on lower freqs.



I also tested it by purposefully clipping the amp (reached 160w, definitely clipping) and noted how it sounded when the amp clipped. It sounds like a high frequency ringing, and it should. I didn't test clipping at low freqs.


Now I'm convinced it'll be great as soon as I get the enclosure built.


For now, it's all testing.
 
#20 ·
Here is my current bass response. Now you should be able to see very obviously why I think it sounds thin.



These were taken with a mic I had lying around (so it is no doubt off) and my sound card has a high noise level (no line in), likely lowering my actual peaks and dips. I plan on fixing that soon. Smoothed 1/3 Octave.




The upper measurement is with bass boost enabled and the lower one without. Really I don't use the bass boost as it's battery powered and I would have to replace a lot of batteries if I did. I found it weird that the response drops at higher freqs.
 
#22 ·

I am confused? Crossed over that high? Where did I reference the crossover? Sorry if I am being stupid...


After some thinking, I am guessing about 80hz will be best for my situation.
 
#24 ·

Quote:
Originally Posted by dbldare /forum/post/17826834


You graph just looks pretty strong above 100Hz, up to about 120ish.



dbl

That's why I was asking about your crossover. It looks good up to a little over 100 hz. If you are going with an 80 hz crossover you will be fine. A little more on the low end will help so your new sub will be worthy of that.
 
#25 ·

Quote:
Originally Posted by brandonnash /forum/post/17826999


That's why I was asking about your crossover. It looks good up to a little over 100 hz. If you are going with an 80 hz crossover you will be fine. A little more on the low end will help so your new sub will be worthy of that.

Yes, I would say 50-80hz needs some help, and then a nice 2-octave range increase



I have not measured my surrounds (too lazy to disconnect the mains), but I believe that they go a bit lower than the mains, and their drivers have more throw.
 
#26 ·
Yesterday, I got a circle cut, but I don't have a camera or a cell phone. I will try to get some pics, though..


We are working on changing a few things so we can do this 'smarter' instead of harder.


The final idea is, I believe, double thick on top, and then triple thick on bottom, with another 'plate' for the bottom.
 
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