Hi Evren, Our European division handles our sales in Turkey and they have some alternate products that we do not carry in the US so we may not have the images. Please email firstname.lastname@example.org and he will be able to help you get any images that you need.
You can purchase MTX products directly from our web store at mtx.com or through one of our authorized dealer affiliates.
For all car audio products you are backed by our 30 day money back guarantee and our standard mobile warranty, you can get all the details here, https://www.mtx.com/warranty_mobile. If you have a non car audio product you still are covered by the 30 day money back guarantee but the length of the warranty varies by product. Check out those details here, https://www.mtx.com/warranty.
A sealed enclosure is going to give you the best SQ for your subwoofer. The box needs to be built to the proper specifications in order to achieve that, the best subwoofer in the world in the wrong size box will still sound bad. Call or live chat us and we can help you build a box that will work for what you are doing.
A vented enclosure is going to give you the deepest bass. There are a lot of ways that a box can be built that can impact the sound and also the parameters of the subwoofer will dictate how low it will actually play. Our tech support guys have a great program that allows them to input the dimensions of the space you want to use in your car to determine the best box design for the subwoofers you are using. You can call them at 1-800-225-5689 or live chat with them to take advantage of this.
Choosing between a sealed or vented enclosure is going to be determined by a few different factors, including what type of music you listen to, what type of bass you are interested in reproducing, how much space for an enclosure your vehicle has, and the subwoofer(s) parameters. The bass is "boomier" from a vented enclosure so if you listen to rap, hip hop, or other genre that has a lot of bass a vented enclosure is going to be able to generate more SPL and be louder. It is not going to be clean sounding and you will probably not win any awards for sound quality but people will definitely know you are bumping. A sealed enclosure has a tighter sounding bass, like from a kick drum usually found in rock or country music. A vented enclosure requires a bigger box because it has a vent so this style box will take up more room in your vehicle. So if you do not have a lot of space you are going to have to choose a sealed box or a smaller subwoofer. Some subwoofers like our FPR shallow subs are specifically designed to be used in a sealed enclosure and are not recommended for vented enclosures. Now I don't know anyone that just listens to one kind of music so generally speaking more often than not people choose a vented enclosure over a sealed enclosure unless they are absolutely limited by space or are truly interested in a SQ system.
It is important to remember that the gain is not a volume control, it is designed to match the output voltage of your source so that you get the best performance between your amplifier and speakers or subwoofers. Check out this video on our YouTube page that shows exactly how to set the gain properly, http://www.youtube.com/watch?v=bRzn1KCX2sQ. You can download the 50Hz test tone from any subwoofer page on our site in the Support Files tab and the 1kHz test tone can be found in the Support Files tab here, https://www.mtx.com/thunder75-4-mtx-car-amplifier#product-supfiles
Bridging an amplifier is often most useful when you have a 2 channel amplifier you want to run as a mono channel or a 4-channel amplifier that you want to run as a 2 channel amplifier or if you want to combine the rear channels to a single channel. Bridging is the combination of the left and right channels of an amp, using one terminal from each side, to make 1 (mono) channel with a higher output than either channel running separately. Remember when you bridge an amp the impedance is going to be different so make sure you are using the correct subwoofer or speaker. If the amp can play at 2Ω per channel, when you bridge the channels they will be at 4Ω.
A mono-block amplifier has only 1 channel and cannot be bridged. The 2 outputs of a mono-block amplifier are there to easily connect multiple subwoofers. If you're not sure whether your amp is a mono-block or a multi channel, look at the speaker terminals. Multi channel amps are labeled left and right, and mono-blocks are labeled speaker 1 and speaker 2.
Every amplifier has different requirements for bridging, so consult your manual before making any connections.