Jkm3141

Well thanks for the advice guys, I mainly just wanted to know if the speaker placement would cause that. I know that Type R's sound good ported, Ive heard some good setups with them before. I am building a box tomorrow for them and pulling the BTL to run the Type R's for a few days to get a feel for them. When I tested the speakers the other night it was mainly just to see if the speakers were in working order. It was 3AM and I just wanted to ask if its not unreasonable for them to sound like that. That's all. Anyhow, I'll let you guys know how it sounds ported. I guess I really have no idea what ohm these coils are until I get my multi meter on them, I thought that they were DVC 4 ohm since I saw that some are. I didn't realize that this much of a 'production' common speaker would have options like that, though its good that it does. Anyhow, my noob moment is over now. - John

Thanks, that makes sense. All I was asking was why I got the results I did from a stupid test. While I can move it in and out of the car by myself, Its not exactly fun to do, and it wouldnt be any kind of easy to get it in my basement apartment, so for a quick test I didnt bother taking it out.

Guys, I get that it should be ported. I am building a box this weekend, I just never realised that the position of the speakers in the car actually mattered that much. And I assumed that Type R's were DVC 4 ohm. If I knew they all were I wouldnt have asked. - John

I am completely stumped on this one. To start off, I feel I have a decent understanding of ported enclosures and basically every ported box I have built on my own has sounded good. However, Whenever I build a sealed box for a friend, I am NEVER satisfied with the sound quality. Here's a little back story on what I am doing. A good friend of mine has two RF Punch 12's (I would hope P2's, but considering he paid about 400 for the whole system (box, amp and two speakers) new at best buy they are probably P1's. He has been wanting more bass for the longest time, however could not justify buying my old Audiopipe 15's when I was selling them. Another friend of mine had two older Alpine Type-R 12's he used to use. AFAIK they are in perfect working order, minus a small hole in the dust cup on one of the alpines (has been repaired decently, I do not see that affecting SQ at all). The logical thought for me was to get the two Alpine 12's, build a nice ported box for my friend and find him a deal on a legit 1000W amp somewhere. That should give him a huge improvement over his sealed Punch's. Yesterday I picked up the Alpines from my friend, I pulled them out of the sealed box they were in, double checked the wiring, as I had no clue how this box was internally wired three years ago. Now I assume, and this is confirmed by everything I read, that Alpine Type R's are Dual 4 ohm coils. Tonight I went to a parking lot (damned neighbors hate me), and with the 12's sealed box sitting in my backseat (as the trunk is full of a LOT of BTL box and I cant really remove that by myself) I wired them to my Hifonics 2000W amp at 1 ohm, and proceeded to tune a system like I normally would (set the gain at zero and adjust up...). I wanted to test the speakers, and have heard two sealed Type-R's before and they can get quite loud in a sealed enclosure. However, no matter what I set the gain at, the SQ is just terrible, and I get very little beat out of the setup. Unless I somehow had it wired at 8 ohm instead of 1 I do not see how it could sound so bad. I wired each speaker down to 2 ohm (Pos to Pos, Neg to Neg) and then connected the Pos and Neg coming off the two speakers in parallel to the amp + and -. I also re wired it to the way Hifonics recommends you wire two 2 ohm speakers to the amp (4 terminals, kinda hard to explain at 3AM). I guess what I am asking is, How critical in the car is the placement of a sealed enclosure? I have a station wagon, so the airspace of the car is obviously very well connected, and I assume that having the subs in the back seat wont affect it nearly as much as I am seeing. Tomorrow I will get together with the friend with the car these will be installed in when I get all issues worked out. I will throw them in his trunk and wire it to his current amp, and if these arnt at least as good as his Punch's, I will really be confused. God I feel like a moron, I cant wire in the most common simple setup of two sealed cheap 12's, but I have no problem dealing with my BTL... ???? :01nocomment8so: Ported FTMFW - John

Had two of them on my old two Audiopipe TXX-BC15's, Both of them broke within a month of installation. Fortunatly got a refund on both, but I honestly wouldn't recommend it to anyone. Yes, its a cheap way to get power, and I have heard great things about them *WHEN* they work. Its designed to be externally fused, and obviously doesnt do rated but is better than most Power Acoustiks.

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Damn, that sucks man. I've always mentally thought that the 'Huge' ported boxes that we tend to have would deter people when compared with a tiny prefab sealed box. I guess not... Though It does take at LEAST two people to get my box in if you have every door open and the trunk so mabye there is some truth to it. Either way, sucks to have stuff get jacked. My friend had his two 12's, amp, and DSLR camera taken about two months ago. Broke out a window and everything. Too bad his car was unlocked. - John

Yeah... well I have had the 15's for a while and like to change things up. I hopefully can sell the 15's for close to what I paid and all should be well. I hope I can sell them fast as that will pay for a battery or alternator or both.... :-D - John

Well I got the Fi 18" BTL in the car. I picked it up on Car Audio Classifieds and built a box yesterday. It is a 6.7 Cubes tuned to 32 Hz, 4 inch port. I am running it on the same amp (Hifonics Brutus BXi 2010D at 1 Ohm) and same settings as I ran the two Audiopipe 15's and it sounds great. It is noticeably louder but not insanely louder. I am having power issues as my voltage is dropping when I crank it, so I will approach that problem next. I appreciate your guy's help with this though. That speaker is just massive in person though, No video or picture does it justice. I plan on repositioning the speaker a few times to see what sounds best. I like speaker + port back, however in that trunk it is pushed so far back that it blasts right into the hatch. I will try speaker + port facing both up and forward and see whats best. Again thanks for the help on the box. I am very glad I went with that 18". Even though I am probably not even feeding 1500W into it, it sounds great. - John

Well I built a 6.4 cubic ft box yesterday and threw my speakers into it today, and I gotta say that it sounds loads better. I went with a center port again, however 3 inches wide and it sounds good. Also, I have another question of a different sort. I have been looking into a single Fi BTL 18" for a while as an upgrade. I would build the box between 6-7 cubic feet as that is the most I can comfortably fit in my trunk. As for the box design, I am wondering what I need to do to support that kind of speaker. Most people I see use at least 1.5" MDF for the speaker surface, and some kind of internal bracing. How much strengthening is nessessary to support 3-4kw of power from a BTL? Thanks for all your guy's help. - John

I kinda think thats whats hurting me now. A Lot of the box area of my current box is port. However the 5 cube number I am coming up with is the entire box, not minus the port. - John

I've been using that for a while. Great site. However the 12-16 square inches number is a useful thing to know.

Thanks for those rules of thumb, I am trying to learn box theory and it is quite hard to get good information on. Any specific design on the port, or just one rectangular port going back. Like I assume things sound totally different with a 2 inch wide port going far back versus a 4 inch port going half as far? The port on that 5 cube box is rather intricate, as it is not just a single rectangular port going back which is why I ask. After posting earlier, I went and messed around on my setup a bit, and after facing the box down where the port and subs are facing back, it sounds a lot more like my old box, but still doesn't hit the low's as well. I just assume its starved for air? I am also confused as to why the whole system isn't a bit louder, since 1ohm on that Hifonics amp should be pushing at least 500W more than the old Power Acoustik was at 4ohm. I might not be pushing the amp far enough to have noticeable volume differences, but I want to get the box situated first. Anyone know any good reference sites on port theory? I'll let you guys know how it works out, I plan on buying wood tomorrow after reading some more. - John

Hello, I posted my first dual 15 setup about two months ago and was told by several people that the box design was holding me back. I recently took a vacation to west virginia with some fellow audio friends and built another box while down there, to my friends specifications, and am seriously unhappy with the way it sounds. I was wondering what approach I should take when building a new box, something I would like to do this weekend sometime. My first box/setup is shown here, It hit very hard and hit a LOT of very low notes by comparision to other systems I have heard. The only issues I had with that box is the size of it (7 cubes) and that I had no good place to mount the amp (Amp blew up recently, I assume due to being mounted to the box). The port on that box was 2 inches wide, and about 8 inches back. My friend who helped with the design of the second box said there was no reason to have the box that big and also said the port completly wrong on the first box (not big enough, not far enough back). He went ahead and designed a box which had the subs and port facing up, with a 4 inch port in the middle. The port goes down to 4 inches from the bottom and splits towards each side of the box ending about 4 inches from the sides. The new box is 5 cubic ft and fits much better in my trunk, and from what I was told it is tuned to 34hz. Also, I did not replace the blown Power Acoustik A3000DB amp with the same model, as I am sick of Power Acoustik issues (my friends have had terrible luck), so I picked up a Hifonics Brutus BXI2010D amp and planned on wiring it at 1Ohm instead of 4Ohm like the A3000DB. This should be netting me a max of 2000W instead of 1200W. My impressions of the new box are that it punches beats much nicer, making rock sound loads better. but it just cannot hit constant notes with any kind of force. It does alright on higher frequencies but not low frequencies. I cannot seem to understand why it cant hit the lower notes better if its getting at least 500W more power and is truely tuned to 34Hz. My only guess is the smaller volume of the box is really holding it back. Audiopipe specs the TXX-BC15 speakers I have to between 3-3.5 cubic feet per speaker. Would a drastically under volumed box cause these problems? What type of design should I use when I create the new box. I really am up in arms about speaker enclosures now as the box that seems wrong for all reasons sounded much better with less power than the box that appears to be meeting all specifications except volume. I appreciate any help, I know you guys will be able to hook me up with a good design. I can build nearly anything once I get a good design thought up. - John