Help wanted: Newcomer to DIYAudio and acoustics

[Lane P]

Hello, I've been working on putting a car stereo in my '89 Mustang hatch. I've decided to use Sony Xplod all 'round, including two 12" 1100w Subs. As of a few days ago, upon stumbling on the topic of bass reflex and bandpass sub boxes with a friend of mine at school, my intent was to build a simple sealed dual enclosure with a dividing wall between the two subs. After looking at the other box designs and reading about the differences, I would like to build a bandpass box (preferably) or a bass reflex box instead. However, I know very little about acoustics and resonance when air is in an enclosed space and about how different enclosed air volumes affect sound output.

[toylocost]

If this is your first build I would recommend sticking with a sealed box. Build that, listen to it, then build something else. Bandpass boxes have a their purpose but I wouldn't use one in a car if you want your music to sound good. The Sony subs will have a recommended sealed and ported box volumes, stick with that for now.

A better forum for you to read is the SMD forum, there is even a free box calculator that you can download in the subwoofers/enclosures section. That forum is all car audio and they will be able to help you better. After you get bored at SMD you can go to the DIYMA forum which is more oriented toward the higher end car audio, mostly SQ.

[ODougbo]

I’m new to the forum but building speakers since…well a long time. There are just things some DIY folks will never agree on. Sealed, ported, band bass.

Advantages of vented enclosures:
• Higher average output than sealed
• Tuning frequency can be easily adjusted by changing port length
• Deep bass response with lower power requirements
• Great for high output with limited power

Advantages of sealed enclosures:
• Small enclosures
• Linear (Flat) response
• No port noise
• High power handling at all frequencies
• Excellent for sound quality
• Extended low frequency output when compared to vented enclosures

Personally, I like the vented boxes, you can tune them up and they have an extra throaty sound.

There are huge discussions about the type of material to use (sheet goods), Baltic Birch vs. Home Depot MDF (which is very reasonable priced).

A lot depends on your skills/tools/budget and shop time available.

[dangus]

I've rarely heard or felt nicer bass than I had in an '81 Mustang hatchback, with one 10"sub in a sealed box. So I vote sealed, using a driver (and box) that model with an F3 almost good enough for a home subwoofer (in the 30 to 40 Hz range). That may not deliver a flat response in-car, but it sure felt and sounded good.

Efficiency isn't an issue in a car unless you're competing for SPL. I'm currently driving around with a 12" AVI woofer powered directly from a head unit which delivers a whopping 10 watts; I wouldn't describe that as "enough" bass but it's loud enough to feel.

[ODougbo]

Yes I know I lot of people love the sealed boxes, this fellow may like them also. They never did much for me, but I like the low, low, bass. I do smile when it rains, the bass reflex speaker(s) will dip down even lower, due to lower air pressure I assume. The sealed boxes always “sound the same.”
There was a head installer that I met once that was to the point of being annoying, boasting about sealed boxes, ok uncle; I guess they are okay, but not the only thing around; there are a lot of tradeoffs with speakers and design.
They keep improving the drivers, most of the name brands are going to all handle a lot of power (sound better too), more than most people, want need; so worriers with over powering in any of the designs.