Single or Pair of 'X' for HT use?

**bumpnzx3** · **11-28-07, 08:27 AM**

I ordered a pair of your 12" X series- one for a friend's car stereo I am installing, and one for a daily driver.

Curious to know if you think they would be good for HT use? I realize I'm not going to get earth moving bass- that's not what I am after. I am building a budget DIY system. The substage of my current HT (which is being rebuilt) is a 12" Sony powered sub 120 watts I believe (around 5 years old). I am happy with the volume it's capable of- but it's a tad muddy. Think a single X (or pair) is capable of that volume (with a different amp of course)?

12 DUAL 4
Fs: 25.7 Hz
Re: 3.9 Ohms/coil
Qms: 4.01
Qes: .38
Qts: .35
Mms: 120g
Cms: 3.2mm/N
Sd: 480cm^2
Vas: 104.1 l
Spl: 88.6dB 1W/1m
Bl: 20.0 N/A
Xmax: 16mm
Rms: 300W
Sealed box: .9-1.3 cuft
Ported box: 1.6-2.2 cuft
Sub OD: 12.500
Cut ID: 11.125
Mounting depth: 5.750
Displacement: 0.10cuft

Would someone mind putting this info in WinISD Pro for me- and sending me the file? I did it, but I am new to the program, so I don't know if the info I am coming up with is correct.

**bumpnzx3** · **11-28-07, 02:13 PM**

Nevermind- that's a pretty broad question. Can someone just put the info correctly into WinISD for me- and email me the file? I want to be sure I have done it correctly before I start modeling things.

**Ricci** · **11-29-07, 09:43 AM**

These model quite well for home theater and even one should make your Sony look silly. I'd still go with 2 of them to make the Sony crushing complete.

How big are you willing to go with your enclosure/s and do you prefer sealed or ported? I'd go ported with these to maximize their potential but the boxes will be kinda chunky. How low do you want to go?

**bumpnzx3** · **11-29-07, 09:54 AM**

I figured out what I was doing wrong in WinISD. I was finally able to model them last night. This is my first venture into real HT. Currently all I have is that sub and RCA satalites, bookshelfs, and center channel. I have been a car audio buff and recently decided to get my feet wet in building a descent HT system.

Normally in cars- I always preferred a sealed setup. However, from what I read HT is a different animal. Besides- those certainly modeled better ported than sealed. What looked fairly good was around 4cu together or 2cu each, and tuned in the low-mid 20's. I had a single TC Sounds DB-500 I was thinking of using (a little more xmax than the Fi X)- but a pair of Fi might be the way to go. Mainly because.....well, nevermind I will keep my opinions of what TC has recently done, to myself.

**bumpnzx3** · **11-29-07, 10:03 AM**

from what Scott said- these don't go ultra low all to well. i would guess because of the xmax limitations as well as possibly being somewhat low on power capabilities.

**Ricci** · **11-29-07, 03:51 PM**

4.4cuft with 2 4" flared ports tuned to 20hz looks good. Thats for each driver. So 8.8ft total. 350 watts is all you need for each driver in this set-up, and you should have solid output, 110db+, from 18hz up with the pair. The 2 4" flared ports on each 12, keep the vent air speed nice and low.

**bumpnzx3** · **11-29-07, 06:13 PM**

I must be doing something wrong. That graph doesn't look all to good to me.

Also- Scott was saying a pair of these would be best in a med. size enclosure. Who knows though- your graph probably looks good. I most likely entered something in wrong.

When I enter the sizes you are saying (single driver, 4.4cu, 2x 4" ports)- it's telling me I need a port length of 38" and it appears to be about 3-4db lower across the board?

**Ricci** · **11-30-07, 11:54 AM**

4.4 cu ft is medium sized or some would even say small. Remember this is not car audio. HT requires much larger enclosures and deeper tuning for vented boxes than car audio, where you get a ton of cabin gain and you only listen to music which rarely has bass lower than 30hz. HT has a lot of bass between 25hz-16hz or even lower. The 2 4" ports would both need to be about 35.5" long to tune that size box to 20hz.

The graph that I'm getting is about 4db down at 24hz and -6db down at 19hz. Looks pretty good to me. It should flatten out quite nicely with a little room gain. Usually you don't want a perfectly flat response because of room gain at the lowest freq's.

**Fi Audio** · **12-01-07, 03:37 PM**

4.4 at 20 would work well. And yes, that is a medium sized home enclosure to most people... but to those from the autsound arena, that is a monster

You could get away with a single 4" aero if it becomes an istallation issue (although at 4.4 cuft you could easily run a 90 in the port, or terminate the inner flare about 1.5" from the back wall and gain a little on the tuning from that as well.

Having the shelf in the bottom end response is similar to that of a car... isnt an issue at -4dB down that low as room gain will flatten that right on out and give another couple of Hz of usefullness as well. Car audio "cabin gain" is significantly higher and having -25dB at 20Hz often equates to a flat in car response. Gotta love the 20+dB of boost down low

This is why you can get away with .8 cuft sealed in a car for a 12 and still have a nice smooth flat response... it is also why people can rip heads off in a car with 1000W

Thanks,
Scott

**bumpnzx3** · **12-01-07, 03:40 PM**

i need to get out of my car audio mindset

Scott- I sent you a PM about getting another 'X'.

**bumpnzx3** · **12-01-07, 03:49 PM**

I did some measuring. I don't have the room for 8cu in one spot. However, I've got the room for 2x 4cu enclosures- 1 on each end of the couch.

**Ricci** · **12-02-07, 11:26 AM**

It feels pretty good when the driver mfg'er backs you up

I was actually thinking that 2 boxes would be better anyway. That way they are lighter and you can be more flexible with placement.

What kind of enclosures do you want to do? MDF boxes, sonotubes, or maybe even something else? If you didn't want to bend the ports you could go with a sonotube design. You could go with a slot port too.

**bumpnzx3** · **12-02-07, 12:21 PM**

I haven't decided yet. Either MDF or Sonotube. I've got a boat load of both out in my shop. I did a Sonotube enclosure for my car audio setup I just finished up. I didn't end up using it because it didn't look right. However- I had to buy an entire section- when all I needed was about a 16" long piece. Needless to say- I've still got some laying around to make larger HT enclosures.

http://share.shutterfly.com/action/w...r&linkid=link5 About half way through theirs picture of the Sonotube I built. I've still got a little cleanup work to do in the trunk- but that's more or less the finished product.

**bumpnzx3** · **12-03-07, 10:06 AM**

I won't be down firing the subs- but which direction would be best? Forward or up? Also- which direction should the ports fire- up, forward, or towards the wall?

I have two couches on adjacent walls- with the arms of said couches touching. That leaves a square shaped area of dead space. That's where one of the subs will be located. Should that one fire up rather than forward/into the couches?

**bumpnzx3** · **12-03-07, 10:47 AM**

josh- just received your graphs. for some reason your email server keeps rejecting my reply....

that does look quite nice. looks like i've got my answer. now i need to go back through and check my work- my graphs didn't look quite like that.

thanks for spending the time on that- much appriciated.

**Ricci** · **12-03-07, 12:37 PM**

You did get them? Awesome. I didn't think they got sent. My e-mail at work was acting real buggy due to my mailbox being Hella full. We keep e-mail archived for years.

I think you should forward fire the ports and the driver on the same face. You'll probably have to bend the ports in the cabinet.

**bumpnzx3** · **02-26-08, 12:59 PM**

Work was nuts and things with my Benz project came up. I am just now getting back on the HT project.

I was doing a little more thinking/planning/measuring last night. You guys decided each sub needed 4.4cu, 2x 4" ports @ 35.5" - right? I also assume that means each port should be 35.5"?

With that being said, that's going to take up a lot of volume- which means each enclosure is getting larger.

Port Radius = 2" = .166'
Length of port = 35.5" = 2.958'

Volume of a cylinder (port)= pie * r^2 * length

Plug and Chug----> 3.14 * .02755 * 2.958 = .25588cu per port

.25588 * 2(ports per enclosure) = .51176 of total port volume + .10cu for sub dispacement = .6117

4.4cu airspace + .6117cu = 5.1cu per enclosure right?

As I said before- in the car world, I only like sealed. I know a sealed enclosure isn't extremely picky on volume. With that being said- do I need to take into account the actual ID and OD of the PVC pipe I will be using and refigure my calcs. Or is it ok just to add .10cu or something of the sort and call it good?

**bumpnzx3** · **02-27-08, 09:51 AM**

I just picked up a 500 watt plate amp for the pair to share. A little short of the 350 watts Ricci suggested per sub- but 250 each should be good. I couldn't really justify the added expense of jumping up to anything large than 500 watts. Especially considering the caliber of the rest of my equipment. Not to mention the fact I am happy with the output (not clarity/sound) of the single 120 watt Sony that's currently providing the substage.

**Ricci** · **02-27-08, 04:00 PM**

Which amp did you get, Oaudio? Since you are using one plate amp did you decide to go with one big enclosure?

Regarding the cabinet volume. You should subtract the volume displced by the ports as if they were solid. Don't forget to subtract for the space that the driver and bracing displaces too. At the end of the day though, it doesn't have to be perfect, just get it in the ball-park.

**bumpnzx3** · **02-27-08, 08:27 PM**

I went with the Oaudio/Bash. The enclosures are still going to be split- one on each end of the couch. I think I am just going to build something to house the amp and put it behind the center of the couch- and run speaker wire in each direction. I couldn't find any other cost effective way to get 500 watts and seperate enclosures- given the VC configurations of the subs. If I just had single 4ohm VC- I could have just bought 2x 250 watt Bash plates for the same price- but that won't work out to well with d4 subs.

**bumpnzx3** · **03-05-08, 12:29 PM**

I got a good jump on the build this past weekend. I realize a flared port is more or less a must. I am planning to buy an off-the-shelf flared port for the inside of the enclosure. For the "exhaust" side- can I just use a roundover bit on my router and call it good? I think that would make for a cleaner look on the finished product, rather than having a port screwed on the outside.

**Ricci** · **03-05-08, 05:00 PM**

I don't see why not. Post up some pics when you get a chance! GL with the build.

**bumpnzx3** · **03-05-08, 05:17 PM**

I am getting ready to go out to eat with my parents. When I get home tonight, or possibly tomorrow, I will upload some pictures.

Saturday I spent the day cutting up the wood. I got to use my tablesaw for the first time- much quicker than the circular saw I am used to. I didn't get much else done besides that though. My dad came over and we finished up the brushed stainless backsplash in my kitchen that we had been working on for a little while, as we had time. I will post pics of that too- it's more impressive than the sub

Sunday I started joining the pieces together, and finished up joining all of them, aside from the front baffle and top piece, on Monday night. Last night I spread wood filler over all of the screws, which I had to forsight to countersink prior to assembly. As the filler was drying, I measured out and marked the locations for the driver and port holes. I was planning to do some sanding tonight, but I forgot about having to get together with my parents.

One thing I need to do though is come up with a way to make some feet for the enclosures. Just sitting them on the floor, leaves them just a tad shy of being tall enough to pull double duty as end tables on each end of the couch. The shouldn't be too hard though.

**bumpnzx3** · **03-06-08, 07:58 PM**

Don't mind the old school couch that's out in the sunroom/front porch as well as the side of the living room. I bought new couches a while back- but I had to keep the two old loveseats so my pitbull would have his own place. I put one out in the sunroom for him and one on the side of the living room.

At first I only filled/sanded the screw holes. Then I decided I would put filler over all of the seams also- since I haven't decided on a finish/veneer just yet. I don't want the seams to be seen if I decide to paint it.

The plan is for each of these to be located at each end of the large couch in front of the tv.

**bumpnzx3** · **03-08-08, 07:50 PM**

I was able to get some more work done today. I was able to get the port tubes cut/measured, cut the front baffle, drill and countersink the front baffle, cut all of the holes for the ID/OD of the driver as well as the ID and OD of the port tubes. Overal- it was a pretty productive day. Everything matched up well- even the port tubes to the front baffle.

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