Tamas

iTrader: (1)

Since I'm about to replace my speakers with 6.5" 2-way components in front and good quality 6x9 in the rear, I was wondering what kind of enclosure (if any) should I use, especially for the component 6.5 speakers in the door? Is there a lot of benefit to have an enclosure vs. mounting the speakers "free-air"? What about the rear speakers?

If it is beneficial, where could one get such things? I can't make these myself, so are there any online vendors where good enclosures are available?

Thanks.

Sputnik

Most component sets do best w/o enclosures, as they are designed to work "free air", also known as "infinite baffle".

What you should do is make sure that the the door panel or rear parcel shelf is sealed, keeping that "infinite baffle" (remember, the "baffle" is the board that the speaker is mounted to). When a speaker cone moves forward, it creates slightly higher pressure in front, and slightly lower pressure in the rear. When the cone moves backward, the opposite happens. This oscillation of pressure waves is what creates sound. Pressure always tries to equalize itself, so if there is a hole in that baffle board, some of that pressure will sneak back through that hole, instead of towards the listener, decreasing sound quality. How much depends on the amount of "leakage", and how low the frequency is.

Yes, the ski-hole in the RX8 compromises the low-end performance of the 6x9s in the rear parcel shelf, especially when it is open. Audio in the car is all about compromise and trade-offs.

So regardless of the quality of your speakers, the more you can seal off the airspace in front of the speaker from the airspace behind the speaker, the better it will sound, and the bigger the impact it can deliver.

---jps

Tamas

iTrader: (1)

Thanks for the response.
What you wrote is exactly what is hard to achieve however. If I mount the front component speakers in the door without an enclosure, I have no easy way to seal the airspace since the area behind the speakers is not sealed air-tight - and there's no way to achieve that with no enclosure. There will always be a gap at the window, for instance.
I think I'll forget about any enclosure and go without them - especially since I have not found any source that would provide these for door speakers.

Sputnik

Two things.

1) You are correct in that there is no perfect solution, you aren't going to be able to seal that door airtight. There is that point of diminishing returns. Just like the smaller a "hole" is, the less effect it will have, the farther away from the speaker a "hole" is, the less effect it will have. So, what you want to spend your effort on is making sure that everything is sealed on the metal panel on at least the front half of the door, and any obvious holes on the back half. Make sure that the "pop-locks" that hold the panel onto the door have their thin rubber "gaskets" (get some normal thin rubber washers if they aren't present), so it will seal the pop-lock holes better. Outside of that, any holes that you cover in a modern car door will probably not be worth the effort.

2) Free-air speakers are designed to work in free-air situations. When you put them into an enclosure, you restrict them, and they do not perform the same. If we install too small of an enclosure, we will restrict speaker movement too much, and frequency response throughout the speakers range will decrease. If we install a small enclosure on a midrange, middle frequency response will be increased and lower frequency response will be decreased. If we install a large enclosure on a midrange, middle frequency response will be decreased, and lower frequency response will be increased. Even if we install a medium enclosure, the mid-low frequency response will be increased, but middle and lower frequency response will be decreased.

There are situations where a professional (or equivalently experienced amateur) can design an enclosure for certain drivers, so that it will work well with the rest of the system. For example, if the designer of a competition system needs to increase middle frequency response and power handling, a small enclosure on the right driver would produce a better result than using an equalizer (and is where the real art of installing is, IMO). But for us amateurs, it's best to leave them free-air, since we want as consistent, neutral, and balanced frequency response as possible.

---jps

rotarygod

I disagree. I like using a sealed enclosure anywhere I can get it. This includes around the mids whether in the doors or a rear deck. A 6X9 I wouldn't enclose but I wouldn't be caught dead with one anyways. There is alot more to an enclosure than just low end response. The reason speakers typically sound better in an enclosure is due to the fact that you aren't listening to the rear wave come around and cancel some of the front wave out. The rear wave can echo and reverberate inside the door or trunk. While it does this in an enclosure too, the enclosure is generally thick enough to hold most of that sound inside. A door panel is a big thin cavity and much noise can escape through the plastic door panels and trim. In the trunk, an enclosure is important so that the left and right speakers don't cancel each other out from being in the same enclosure (trunk). There is no way in hell I'd run 2 subs in 1 box if they were wired in stereo. Why is this acceptable with mids which are more directional? If you can, build an enclosure. In the sake of the doors, build it as big as you can get it. You don't have a whole lot of room to work with so the biggest that you can get will work just fine. You'll find that the mids will clear up and get much more defined which will require far less equalization to sound really good. Remember that an eq can only correct so much. It can't make up for a bad install.

Kev

I agree with rotarygod 1,000,000% !!!

Fibreglass will probably work best in the doors, IMO, you won't have much space to work with in there. There are some pretty good sound deadening materials you could use in the door cavity directly behind the driver as a bit of a compromise.

Sputnik

Fair enough.

Now just to clarify, you are talking about an enclosure that is big enough that it the acoustical suspension has little effect on the speaker's performance. The intent of the enclosure is solely to completely isolate the airspace in front of the speaker from the airspace in the rear of the speaker.

Is that a correct statement?

---jps