Who doesn't love a good sub / suggestion thread?

[cobbpa]

It hasn't been the most active week on the board & the Mach Audio presale is enticing to me, but I want to be sure that if I purchase one of those subs that it's the best for me in the long run.
Here's my scenario. I'll live in a smallish apartment until May of 2008, then move out hopefully to a little bigger place and eventually (a year or two later? dunno) have my own house. This sub is meant to grow with me . For the apartment, I'm planning on building it into a coffee table. It will have 4, maybe 5 cubes. After that it, will grow. Not sure when or how big, but eventually I'd like an ideal ported enclosure. So basically, I'm going to buy a huge driver now, understand 5 cubes isn't optimal, but then still have it around to unleash later.

Here's my apartment:



So here's the comparison I'm looking at. I included two 15" models, but would really rather have an 18 for down the road.



So there's that...what would be my coffee table sub. Some annoyingly high QTC numbers though, right?

Here they are ported..I did these enclosures pretty quckly, so don't think they're optimized at all. The boxes are 300-500 liters & tunings from 15-20ish hz.



As far as I'm concerned, this ported graph rules out the Elemental Designs model..I was cool with the polycone, but its lack of the lowest of low end is no fun. The Mach5 is just middle of the pack (power handling) and still seems like a great value, but will I later wish that I had the extra output & excursion?

Basically, I'm looking for someone more experienced to chime in and let me know what he would do. Would it be so bad to live with a high Q sub for a year? Well, maybe a couple years, it's hard to tell. I'll probably be pleased by anything right now and really want to be sure I'm happy with what I have when I go big--sonotube style. I want to Mach 5 to win because of its price, but the Fi & SS offerings seem to have some performance advantages. They both have aluminum cones too, don't they? Eh, discuss, liven this place up a little :W , let me know what to do.

[Tommythecat]

Fi doesn't have a metal cone.

Get the Mach 5's - save your money. If you need more output later just buy more. Just think how many you could have for the price of one SS.

[joecarrow]

Do you live in an apartment where you won't anger your neighbors by producing lots of bass? I think my neighbors are pretty cool, but I bought bass shakers for the couch instead of doing a subwoofer. True, it's not the same- but with a window near the TV, movies are best after dark when people don't want crazy bass disturbing them.

A down payment is hard to come up with- I was trying to do that before I got laid off- and you never know when you could use some extra cash.

Rather than spend $300 on woofers, I spent $70 on bass shakers and left the rest in savings earning 5%. The forum will hate me for suggesting this, but please consider it.

If you buy a sub amp, you can use it to power the bass shakers to see if you like the effect. If it's enough, then you just saved money. If it's not, then you already have the sub amp and the bass shakers can go on Ebay.

I have to say, however, that the coffee table idea is good because it puts the sub quite close to you and allows you to get good bass at the listening position without having to turn it up so loud that your neighbors are guaranteed to be disturbed. 120 db output is crazy loud. How loud do you really listen to movies? I tend to hit peaks in the low 90s, with averages in the mid 60s to low 70s. Louder than that, and it seems like the actors are louder than life. If a whisper is loud enough to easily hear from anywhere in the room, it kind of takes away from the illusion. That's just me- how about you?

[cobbpa]

Tommy--thanks for the clarification on Fi's cones and encouragement toward Mach 5. I don't want to consider multiple subs..by the time I can do that I'll probably be thinking about IB and new drivers. Mainly trying to see a single sub option.

joe--the loudness is no problem. I'm still in college and loud music is going on all the time. Having thee definitive output would make me proud . Disturbing neighbors is absolutely not an issue. Maybe after I graduate it is, but I'd rather over do it now & back off it later. Interesting thought about the bass shakers, too. Thanks

[ThomasW]

I'm not a fan of poly cones for subs. Poly isn't very stiff that eliminates eD.

All the other drivers are very good, it's just a matter of deciding how much you want to spend. The IXL 18.4 is the current best bang for the buck. After the sale the price goes up to $250.

The SS Rl-p 18" would be my choice for either a sealed or ported sub with a single driver sub, were money no object.

For a very high performance IB sub I'm partial to a 4 pack of the Fi .Q18"s, since we get those for the cost of the .Q15" when 4 drivers are purchased.

[cjd]

Thomas, you think the Fi's will outperform the IXL18's for IB? It looks like they don't roll off as fast (given the Fs difference I'm not really surprised)...

[cobbpa]

I thought the SS 18" had a Q of .5 in IB..doesn't that mean it's pretty ideal too? Although I didn't know about the pricing break from Fi..that's pretty sweet.

[cobbpa]

Update: Seeing as the preorder is ending soon and I have yet to find summer employment, I put the $20 down for the Mach 5 IXL. If I get a job I might have to opt for the SS 18, but for now, I'm happy. I think I'm going to seek out a Carvin HD 1800, that give me room to grow into other subs later on. Or the Nady XA 2100.

Now, how to make a somewhat portable 5 cube coffee table? Hmmmm...

[joecarrow]

Wheels.



Seriously, 2 feet on a side, a foot and a half high- that's not so big for a coffee table. The worst part will be weight, if you build it properly. If you found a way to make it a cylinder, that could help reduce weight a lot.

One of my old pet ideas was to use beer kegs as subwoofer enclosures. They're not that heavy for how stiff they are. I think you could fit two 12" woofers in one, and lay it on its side. with more advanced fabrication capabilities, a 15" could be fit. Line the walls to kill the metallic ringing, and it's a neat thing to put a woofer in. Definitely needs a linkwitz transform.

[cobbpa]

I mean be able to move it from home to my apartment & back again. It seems like it will be difficult. I'm planning on using birch plywood to try & minimize weight, but beyond that..I don't know if I should make parts of it removable / collapsable, or build it in a couple pieces or what. I guess it really isn't THAT big.

Cool idea with the kegs!

[Inu_Yasha]

I mean be able to move it from home to my apartment & back again. It seems like it will be difficult. I'm planning on using birch plywood to try & minimize weight, but beyond that..I don't know if I should make parts of it removable / collapsable, or build it in a couple pieces or what. I guess it really isn't THAT big.

Cool idea with the kegs!

I've been saying that I am going to take a pic of my sub... Hopefully today I'll get a chance to upload some pics of mine. I did my sub in birch and it is really heavy, as in around 80lbs for a 5ft^3 enclosure. I did an end table design with mine but ended up using it as a normal table for my school books.

Hopefully later tonight I'll upload a pic; gotta finish my "design a lightpole" project first .

[Inu_Yasha]

Ok, as promised here's some pics. Sorry it took so long to take them, but I for some strange reason decided to visit my folks down in Gulf Shores, AL. Anyways, my sub is a RL-p15 in a 5 cu*ft box vented and tuned to 16 hz (bent pipes).

http://www.geocities.com/masentka1/DSCF0137.JPG

http://www.geocities.com/masentka1/DSCF0138.JPG

http://www.geocities.com/masentka1/DSCF0139.JPG

[cobbpa]

Cool pics, nice work! Definitely doesn't look too far from what I hope to end up with. I wish I had money right now for the SS 18...eh, maybe I'll get lucky and have the cash sooner than I expect. For now it's the Mach 5. What are the downsides to having a smallish ported box? Just less port use / output? I'm thinking I'll keep mine sealed in 5ish cubes, but you've ported yours. Hmmmm

[Inu_Yasha]

I would suggest going sealed actually. I get a lot of problems from the corner loading (I think) because it's ported. It was also a pretty good amount of work to get the pipe with bends to fit into the box. I used 2 5in diameter pipes and ran I think 54 in of piping in there. I JUST got the pipes to be 8 in below the driver.

I would honestly suggest saving up and getting the SS 18! I love my 15 to death and it has great output, but I'm sure later on I'm going to want to add another sub when I move out. Like a lot of people say, "do it right, or do it twice!"

[cobbpa]

Alright, over 2 months later, now my sub is arriving today! I'm still working on the coffee table idea. Updated specs are here. I'm currently thinking about 145 l tuned to 19 hz. Here are the graphs I get for this. I'm posting 2 air speed graphs...one is with a 17cm port I'd have to make myself (modeled w/one flared end), the other is with a 4 inch Precision Port I have lying around. I'd rather use the precision, but is that such a good idea?
Other questions:
Do I have to subtract port volume from the enclosure volume I put into Unibox? As in, I input 145 liters & the port diameter, it says the port has to be X cm long. Does it already assume that's taking up interior volume, or will I have to add that to the end total volume?

Can anyone see any good way to make the enclosure somewhat portable? I'd like to be able to take some of it apart and be able to re-assemble, but as glue seems to be the standard..not sure if that's going to work, but might as well as the more experienced minds!

Currently I'm working off of 36" x 20.5" x 16"h, then probably another 5 inches between the bottom of the table & the base plate. Sound good? I know it's the weak way out, but I'll probably only do single MDF for most of it because of weight. I'll double up the bottom and use several braces. I realize this is at least a slight compromise. Maybe I can find BB somewhere around here..hmmm

Anyone have any tips for making this look pretty nice? I may end up veneering; at least, I'd like to if I get the money. I'm a little scared to do that though, since this will likely get a little beat up..stinkin' college kids partying in my apartment, don't know how to treat things well.

Alright, that's a lot of questions, thanks for any help on this! Pics of the new woofer to be up this afternoon.

[ThomasW]

Unibox subtracts the port area from the overall volume. Line #66 tells the net volume, line #71 is the gross volume. The difference is the volume of the port.

A 4" is port is way too small to use with an 18" driver.

If you're going single layer material don't use MDF.

If you want a smaller box go sealed and use a LT transform circuit to control the Qtc and Fs

[---k---]

PE vinyl veneer may be a good compromise. It will look decent, be easy, and is cheap. If it gets dinged up, easy to re-veneer the whole thing later on.

http://www.partsexpress.com/webpage.cfm?webpage_id=3&CATID=48&ObjectGroup_ID=135

[cobbpa]

Thanks for the answers Thomas, now to see if I can think of a way to get the port to fit in my enclosure while being large enough to keep down air speeds.

Ryan, I'd thought about that..may end up that route, maybe have to use some i have sitting around to see how it holds up to being stepped on & such.

Now..pics! :banana:

[ThomasW]

Oh gees, you're going to de-magnetize that CD..... :B

[cobbpa]

lol...seriously? I didn't know that was possible. If it is, I didn't know it. Eh, it was my mom's anyway :-)

[Raptor550]

Lol, CD's arn't magnetized, they are optical medium. However IF anything COULD de-magnetize a CD, that beast would certainly do it! Careful you cat dosnt mistake that for a bed, or worse, a littler box!

FYI, PE beach veneer is on sale for near-dirt.

[cobbpa]

I've been cutting some wood down for this and my design idea is changing some. Basically, I'm expecting it to be standing upright, not down like a table. Think square sonotube. The base would be 24" x 24". One concern of mine is portability, just if it can fit in my car easily & be moved place to place...I'll have to move it a bunch of times in the next year or two. Right now I'm thinking of making it seperate at the base. I picture the face to woofer is mounted in as double thick and those two pieces not glued together, but when assembled I could apply silicone & use 4 draw latches. It amounts to a box w/a circular hole fitting over the base the driver is attached to. I have some doubts about it, but it seems like the silicone and tight latches could make it tight and not effect performance. If it's a really bad idea I'll just build it all as a single piece, but the ability to break it into 2 pieces is appealing to me. Opinions?

Also, I'm having trouble finding 6" diameter tube...local Lowe's only has it in 10' lengths and they don't carry Quicktube (similar to Sonotube) that small, only 8" which makes the port too long to fit in my 36" long enclosure. Any ideas of something else to look for?

[cobbpa]

This sub will be over a carpeted floor with other apartments below. How should I construct the bottom? I know I'll have the box, then the 6" legs...should I add a bottom plate? Maybe spikes? Basically, quality sound preservation first, but with good thoughts of neighborly considertaions.

[cobbpa]

Posting a graph of what I'm looking at..

[---k---]

Hum, no love yet? I'll offer my non-expert opinion. I think to be a good neighbor, the goal will be to try and isolate the sub from the floor. Therefore, no spikes or anything that trys to couple the sub to the floor. A base plate with rubber feet under it might work well. I'm thinking then you aren't firing directly at the floor? Also maybe look at the SubDudes you can get from places like Sweatwater.com or Musiciansfriend.com . Those are probably too small, but it should give you an idea.

A base plate and isolation shouldn't hurt. In fact, lessening the vibrations in the room and sound from those may help.

[Brian Bunge]

Hum, no love yet? I'll offer my non-expert opinion. I think to be a good neighbor, the goal will be to try and isolate the sub from the floor. Therefore, no spikes or anything that trys to couple the sub to the floor. A base plate with rubber feet under it might work well. I'm thinking then you aren't firing directly at the floor? Also maybe look at the SubDudes you can get from places like Sweatwater.com or Musiciansfriend.com . Those are probably too small, but it should give you an idea.

A base plate and isolation shouldn't hurt. In fact, lessening the vibrations in the room and sound from those may help.

With a big driver like that, this pretty much sounds like an exercise in futility.

[ThomasW]

Any way you build it a 270L wood construction 'box' is going to weigh a frigging TON..... 8O

For a "portable" sub my suggestion is to forget about porting. Run sealed, do a 22"-24" cube. Boost the bottom end with EQ. Install a couple handles like these so there's something to grab a hold of......

[cobbpa]

Yeah Thomas, frigging ton is correct...but I've already built it large for the performance, didn't want to give that up :-) I stared at it a while after I put the 4 main walls together & debated about cutting it down to seal is but knew that I'd kick myself for it later. It's not really a coffee table anymore, more like a sonosub gone square.

I'll do as you said, Ryan, hopefully that'll keep most neighbors happy. Doesn't matter too much...we're all college kids where I live, noise is expected. Just going to try & not be overbearing alllll the time.

Port questions! I am having no luck finding anything 6" in diameter that is cheap. Lowe's here only sells the 6" PVC in 10' lengths & I don't want to spend $30 to only use a little bit. I know, maybe I would down the road, but right now..money's tight. But, I do have access to all the 4" PVC I want. How about three 4" ports? Is there something bad with multiple ports? It gives me a lot of good surface area. The length *might* be an issue, so question...how close can the ports get to the actual driver? Near the magnet? Near the basket? With 3 ports in my box they'd fall somewhere in between those 2 points & I don't know if there's anything bad about being that close.

Another option would be to cut a square & build a port out of plywood. I'm assuming if the square has the same surface area as the port I put into Unibox that the length requirement is the same..right / wrong? Is that a good / bad idea, or should I stick with 3 PVC ports?

Oh yeah, one last question...the panels for the main walls of the box are (interior measurements) 22.5" x 22.5". It's 3/4" BB ply, the good stuff. Right now I have a rib-like square of brace (think just strips glued to the walls) attached in the middle & plan on doing 2 window braces to cut those halves in half. Should that be enough? I'm pretty sure it's good, but just want verification.

Thanks for the help!

[ThomasW]

but I've already built it large for the performance, didn't want to give that up :-) I stared at it a while after I put the 4 main walls together & debated about cutting it down to seal is but knew that I'd kick myself for it later.

Porting provides +3db in efficiency, additional output at Fb, combined with the penalty of higher group delay and worse transient response.

With amplifier power and EQ being so inexpensive, IMO it's hardly worth the weight penalty when one is building something that needs to be highly portable.

Port stuff.......

For optimal performance I consider a 6" port to be the minimum size for a 15" driver, and an 8" port the minimum size for a 18" driver....

Sure you can build a wood port, all it does is add more weight compared to a PVC or cardboard one.

As long as the sum of the cross section of smaller ports equal that of a larger one, using smaller ports is ok up to a point. But don't use 25 - 1" ports....

[cobbpa]

For documentation's sake..

The weekend saw some progress. I think I'm going to end up doing a small roundover on the box edges & putting fabric around it--seriously, like a squared tube sub. Heavy as can be though, but it shouldn't be too bad; I plan on borrowing someone's truck or minivan to take down all my speakers & stuff when I move into school in the fall. I will be open to the possibility of buying Sonotube if I ever find some around here, but I'm not too worried about moving it. Anyway, here are some final graphs based on pretty exact numbers. I just didn't end up having the length necessary to use a large enough port to keep that peak of airspeed down, but three 4" ports appear to do a decent job and I had the PVC on hand.







Ha..here's an action shot!



Surprisingly, my local Lowe's had some pretty nice looking Birch on the shelves. Here's the cutout scrap, it's a double layer.



The speaker in place.

[cobbpa]

Just because, here's one last graph. I'm debating about going smaller...once I start gluing in the window braces & such (in a few days) it'll be the point of no return. Current finished height, after 6" legs + baseplate comes out to ~45.25". I could do the compared sealed box by cutting off some of the box I've constructed to make the finished height 20ish inches. Choices, choices...I live on the 3rd floor, but have myself & other college guys to help me move...ehhh...probably doesn't matter to anyone else, but here it is:

[cobbpa]

More progress! You might notice that one of the ports is 1/2" shorter than the others...this was saw operator error. ops: Unibox tells me that's a ~.12 difference in tuning frequency. I'm not worried about it, but should I be? I used LocTite construction adhesive to attach them to the brace and top panel. It's a busy day today, but they should be done by tonight. Casnio Royale just came in from Netflix, so that could be a fun debut

[cobbpa]

Finally got this listenable over the weekend! :B Sadly, I only had about an hour to play with it before heading back to school, so I was mostly dialing things in...still have to work on that some, but it's location is temporary, so I'm not really worried about getting it perfect. Short story from my little bit of time thus far--it's great! Things were shaking a little, gunshots had thump, the missiles in MI:3's bridge scene were impressive..everything was good. Here are pics from the final build stages, more impressions after this coming weekend. One picture is down a port, showing the few (maybe just a couple) inches of clearance between the basket & end of the port--it was close, but I think it's ok!

[Jed]

Nice work! Pretty Darn huge though and I can't imagine how much that sucker weighs. What color are you going to stain/paint the rest of the cabinet?

[JimS]

Nice!

Looks like it might be a good time to invest in some double-sided tape for those breakable-looking figurines inside the TV cabinet . . . :twisted:

[cobbpa]

Yes, it's a little heavy, but believe it or not I moved it from the garage, up the couple of steps to get in the door, and to that position all alone! Working smarter, that's what it was. :lol:

I'm pretty sure I'm going to wrap it in some sort of cloth material for now--something thick that I don't need to paint under, maybe duck cloth? The endges have a 1/4" roundover to knock down the sharpness. If it turns out to be too big in my little apartment, I'll basically cut off the top & cut the box in half to make it a smaller sealed sub. I really doubt that happens, but I'm going to wrap it in cloth and staple it to the ply sides so that if that happens, the cut off portion will be recyclable into baffles or something down the road :T . And, I just generally count on it looking pretty good with a nice stain / poly job on the top & black everywhere else.

Yes to your post also, Jim...my mom's little figurings don't stand a chance :B .

Anyone care to comment on the bracing I ended up with? Windown bracing was tough to do because of the port length & area they took up; also one would have been inches behind the magnet, so I have three 2" strips of ply per wall. These were cut at 45* on the end & construction adhesive applied to those ends in hopes that would sort of attach them together. Didn't get to feel them for vibrations in my short listening time, but I'll check that this weekend.

[cobbpa]

The 90% final product. Still need to roundover top edges & poly, but it's in place now. My neighbors have mixed feelings.

[myn]

Nice job

Looks really sharp.

Any updates to the finished product?