killa101

The Tacoma Narrows. Thats the one I was thinking of. I could have sworn my professor said it was at its natural frequency, he's such a nice guy and was literally a rocket scientist with a Ph. D. in that field as well as Mechanical Engineering iirc. I'll have to ask him about that again. The FS usually is below the playing frequency right? If you were to apply a decrease in level say, -9db (random figure, not a slope but just a decrease) on all the frequencies there and below to prevent over excursion, would the sub be able to play all the frequencies below? I hate to use 'what if' situations because of the unlikelihood that I'll actually do it. More importantly, is there any other reason than over excursion not to have the sub play at or below its FS? You can play frequencies below the subs Fs without a problem. How deep your sub will play depends mostly on the enclosure being used. If you are using a ported enclosure then you will have a cut-off below the tuning frequency. So your sub will be limited in low-end frequencies below the tuning. To answer your question about lowing the power to the sub...If you were to not exceed the sub's mechanical limits then you could potentially play all the low frequencies. However, you wouldn't really have any audible output. Your sub would basically be playing in free air. You can get your sub to play low but doing so will often require a loss of something else. You will typically need a large enclosure or a very inefficient sub to get the low-end response. The only problem you may have is if you were to tune a ported enclosure to the resonant frequency of the sub. In that case you will have very sloppy bass.

That is correct from my calculation. I should point out that you will only get this voltage at higher volumes. So you would only set your voltage to this level at the highest volume you are going to listen to your system at. This link as well as this link will explain setting the gain with a DMM more in depth. Using the method of using a DMM is fairly accurate and much more accurate then setting it by ear for most people but it is not perfect. Since impedance is different then resistance using ohms law will give you a little bit of error. However, this is a fairly good method and you should use it over using your ear to set the gain on your amp.

1. Post your SSA user name 2. State that you qualify to the terms and agree to follow through with them as they are written above. 3. Post a description of your car and system 4. Post how you plan on helping promote Second Skin including the other web site you will post your build log in. (Rembmer build logs and videos are always better for us) 5. You must tell us something about yourself that nobody on this forum knows about you 1. killa101 2. I agree and qualify to the terms 3. I have a blue 2003 Volkswagen Jetta GLI. It has the premium Monsoon system but I have added a few things. I currently am running a Diamond Audio D6 12" sub and a Diamond Audio D3 600.1 amp. I have a transmission line enclosure that is carpeted and has some suede on the front as well. I have a Pioneer AVH-P3100DVD head unit. The speakers are stock at the moment but I my upgrade to a nice set of components in the future. I have an aftermarket exhaust and a lot of road noise I would like to see if a door pack would help lower. I have some sound deadening in my trunk (eDead v1) and it is okay. I would like to see what a quality deadener can do. 4. I am a regular member of many car audio forums. That includes this forum (SSA), CA.com, CarAudioForum.com, ****, and VWVortex.com. I will post on all of these forums my before and after thoughts, pictures of the install, and an overall review. I will also put a Second Skin sticker in my window if it is provided. 5. I am a college student currently in my last year majoring in Aeronautical Engineering.

They actually have a couple of different types of carpet. They have some in the "speaker building section" here and some in the "automotive" section here. I have used both and both a pretty good for a car enclosure. The automotive is a little thicker and suppose to be a little more durable. Try the links I posted and see if you can get to the pages from there...

I've seen some tests with the 9500 and the V1 and they have close ranges on the highway. My 8500 has never had a problem on the highway and the 9500 is suppose to be slightly better then that. Maybe someone out there has the 9500 and can tell you more about it....

My loudest was in Miami. My friends and I were down there on spring break and were out at night on South Beach. We were walking around the clubs when we heard VERY loud bass in one area. We were walking over there thinking that this club had a great sound system. When we got close we realized it was some guys truck out front! I was impressed and we asked the owner what equipment he was running. All he told us was that it was two 12s. He didn't know anything about the subs or his system. He told us he had another system that was even louder. i didn't get to sit in it though.

I have the 8500 x50 and have a lot of experience with the V1. In my experience the V1 has much better range then the 8500 and is a great detector. It also have the arrows and displays the number of signals it is picking up. The bad things are that it doesn't have a mute feature like the 8500. This is bad in the city because you can't turn off the volume on false alarms. You have to turn down the overall volume which can be annoying. The V1 also has a lot more false alerts then the 8500 because of it's better range. For city driving I would think the 9500 would be better. It is suppose to learn of false alarms and not go off on them. The V1 is going to have a lot of false alarms which will get annoying for city use. I have not used the 9500 so I'm just pointing out what I know. I would choose the V1 for most applications but the 9500 may be better if you only drive in the city.

Looks good so far.... Is it me or are those kicks huge!

Nice and clean, look good.

You could wire a single voice coil on each sub to get a 2 ohm load. That is not a recommended method and it reduces your power handling somewhat. Otherwise you could wire each sub up to a 2 ohm load each. You can't, however, wire both subs and both voice coils up to a 2 ohm final load.

Yes, they are both good subs... What are you looking to get from your sub? That may help us determine what sub would be better suited for you...

Bracing won't really effect the airflow as long as you don't put anything in front of the port. It doesn't really take up that much space if you compared it to the volume the extra wood thickness takes up. I typically use 3/4" with bracing but if you use 1" that is fine.... Having a larger internal volume does typically mean more output and lower-extension. If you make the enclosure too big you are going to have sloppy bass. You don't want to make it too big or the sub will perform like it is in a infinite baffle setup. Styrofoam would work as deadening but not very effectively if you were to simply put it on a panel. Deadening adds mass to the panel which will prevent it from oscillating (or at least not as much). Styrofoam is very light which makes it not very effective for deadening. If you were to put a piece between two panels it could be effective but if you were to simply attach it to a single panel it wouldn't do much. Using resin on the inside of the enclosure is good. It will not crack unless you were to put a very thick layer on. All you need is a fairly thin coat of resin. Most of it will get sucked up into the wood but there will be a thin layer left. The resin alone is very brittle so if you put a lot on it could crack fairly easily. Resin is very strong stuff though so it would be difficult to break. You can add a ton of deadening but there is always a small bit of rattle somewhere. But if you deaden effectively you will significantly cut-down the amount of rattle in the trunk and throughout the vehicle. It would be fairly hard to over deaden but when you can easily get to a point where adding more deadening doesn't have much of an impact. You don't need much deadening for it to be effective. Having two subs facing in one direction and two others facing in the other can lead to phase issues. It wouldn't necessarily be a 90 degree phase but it would probably result in cancellation. Up-firing is not typically good for a couple of reasons in a trunk. The main reason I have noticed is that you will have a lot of rattle on the trunk/rear deck. It depends on the vehicle and the setup if it is really that bad but it is typically not ideal in a trunk.

Im trying to figure it out because if I do test with a multimeter then I can just double check and Id apply it when installing my amps and batteries and what not If you are trying to simply figure out what voltage you should have when you adjust your gain with a DMM you do the calculation below.... V^2 = P x I^2 Where V = voltage, P = power, I = impedance An example would be.... You have a 4ohm DVC sub that is 500w RMS that you wire to a 2 ohm load. You also have an amp that is 500w RMS @ 2 ohms. You would do the formula... V = sqrt( 500w x 2 ohms ) = 31.6 volts So you would set the voltage to 31.6 volts using your DMM. Edit: JL Audio Guide

To determine the tuning frequency you need the internal volume of the enclosure, the length of the port(s), and the cross sectional area of the ports. Did you mean your enclosure has two 3" round ports or two 32" long port? If it is a 3" round port then we need the length of the port and if it is the 32" port we need the port width and depth. You can use this calculator to determine the tuning once these things are known. Otherwise you can post the info here and we can try to determine it.

Curious what about it you love...and of course what it is tuned to I was impressed in pretty much the same way as aznboi as he says below. The transient response is better (compared to ported or sealed applications in my case) and the sound is more defined. It was such a "clean" sound as compared to the previous ported enclosure I used. I don't really know what the frequency is but I know the line length is 86" and it goes from 150% Sd to 50% Sd. It is also fully stuffed which makes the effective length a little bit longer.

I think that you should do that instead. I would be impressed if you could name a thousand subs off the top of your head

I love TLs and have one in my car atm. A couple of things I will say is that you better have a large trunk, lol. Mine is for a 12" sub so it is not so large but for a 15" sub it is going to be a huge enclosure. You probably know this already since you have done some calculations already. Also, it sounds like you are going to make a straight TL. Mine is a tapered TL which means that it starts out at about 150% Sd and goes to about 50% Sd. The benefit is that you can get lower with a shorter length. I also have my TL fully stuffed. That will also help you increase the effective length of the TL. I would suggest messing around with stuffing the enclosure. If you have never made a TL and want to see how it will perform then go for the TL design. I love the way it sounds over any ported or sealed enclosure and also how low it can get. It is not going to be a great output design but with a 15" and 1500w RMS output shouldn't be a huge concern. If you are looking for a little more output then I would suggest a low tuned ported enclosure.

where>? I believe he means if you were to use the kerfed port that you should add the 45 degree angle to both the inner and outer part of the port not just the outer part of the port. I agree that you can just forget the kerfed port. It will not really make a difference in sound. The one thing that I would recommend is the use of bracing. You should use some bracing for the walls of the enclosure. This will help to prevent any flexing of the material.

Yes, I would also recommend using the two ports instead of joining them. I have debated others about the effectiveness of using this design. I personally have been told many times that it is not a proper design and you will get better performance by simply using separate ports. You could always add a piece in the middle like you said.

So is this going to be for strict competition use or more for an everyday use? I'm not surprised to see many different recommendations. It is typical to have many different configurations that the sub can play well in. The issue is that you are going to need to specify exactly what you are looking for from the enclosure. If you are looking for a competition enclosure then you will get a different recommendation then an enclosure for a daily driver.

It looks good... Maybe I missed it but what are the specs of the enclosure?

You can always run a single voice coil of the DVC sub as well. It is not a recommended procedure because it lowers power handling slightly and also can change the T/S parameters. Most manufacturers don't recommend this as most people would not know how to set this up properly.

As long as the magnet is far enough from the back wall to cool properly you will be fine. It won't be bad to have the back wall far away from the sub. I'll let the others recommend what enclosure would be best because I do not have experience with the 12" BTL. I will, however, say that although 1" MDF is nice I would just use 3/4". There is nothing wrong with using 1" but IMO you can get just as good performance with 3/4" and some good bracing. I would use 3/4" MDF with good bracing instead of 1" with no bracing in a larger enclosure. Plus, you are going to be saving money since 1" is much more expensive (at least in my area) and much heavier.

What size port are you using, the 3", 4", or 6" version? Are you planning on using 3/4" MDF? You should have enough space to make that work fine. The only thing that may not be ideal is the port size. Having a flared port helps but the port area is a little small which means you could have port noise. You do have space issues though so that would be the way to go. If you make it out of MDF you are going to want to use some type of protective coating. I would recommend using something like Rhino lining or similar material. This protects the wood from moisture/water.

What are you looking for from the sub? Are you looking to get a lot of SPL, deep bass, or a daily driver? Any info is helpful so we can determine what specs would be best for you.