8" DIY component build

[mustang90]

Haven't built a great system since the early 90's when Orion HCCA amps and Orion Kevlar cone subs were in! //content.invisioncic.com/y282845/emoticons/cool.gif.3bcaf8f141236c00f8044d07150e34f7.gif

I have a unusual type of space that will allow me to use a board big enough to use an 8" driver and any size tweeter. One set for the right, and one left. Each driver and tweeter will have 150 watts RMS. The area behind the board is approximately 2 cubic feet and is not totally sealed.

Keep in mind that this is a budget minded DIY build. I'm not looking for any crazy amount of bass, just a nice clean, full sound. Anything from Parts Express or Madisound useful? I have a few starter questions for those with experience in building component systems.

1. Will an 8" driver setup have any advantages over using a good 6.5" driver?

2. Since the space is not sealed, use an IB type driver?

3. Any budget driver/tweeter/crossover set that stands out above the rest?

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[keep_hope_alive Premium Member]

yes, Parts Express and Madisound are excellent DIY resources. i've bought from them for over decade.

1. you are most concerned about the woofer high frequency response. larger woofers will roll off sooner due simply to impedance (inductance of the coils) and the will beam sooner (lower freq). there are some really nice rull range 8" (Fostex, Dayton)

2. IB doesn't really exist, you just want a woofer with a higher Qts. you also want to be careful of low frequencies and mechanical suspension limits. that said, any speaker will perform in IB.

3. Dayton does a nice job across the board. As do Peerless, Vifa, and Scanspeak. Crossovers will eventually determine performance and can cost more than budget drivers.

i've done an 8" 2-way in my garage using the wall cavity as the airspace and building a baffle. essentially like an in-wall speaker system. you are mostly concerned about contolling resonance of the mounting baffle and airspace. stiffening the baffle and getting some fiberglass batt in the airspace will go a long way to improving performance.

 

[mustang90]

^^ Thanks much!

Yes, the upper frequencies were what I was concerned with versus using a more standard 6.5" driver.

I've used Vifa 6.5's back in 1990 and they were very good. Also used the older large diameter soft dome tweeters.

Any budget minded driver & tweeter combos you'd suggest off hand? Any ready made 2 way X-over that's also budget friendly?

 

[gckless 5,000+ posts]

Here are a couple good 8's:

Usher 8945A 7" Carbon Fiber/Paper Woofer 296-600

The Madisound Speaker Store

The Madisound Speaker Store

Dayton Audio RS225-4 8" Reference Woofer 4 Ohm 295-376

Here are a couple tweeters:

The Madisound Speaker Store

The Madisound Speaker Store

Dayton Audio RS28F-4 1-1/8" Silk Dome Tweeter 275-140

There are more of course, but these are very solid choices.

You have any way to run active? If not, search around some car audio sites, ask some dealers, to see if they offer strictly crossovers at the frequency/slope/power you want.

 

[mustang90]

The Usher driver looks like my cup of tea. Looks like it might be able to reach a little lower than the others?

No way to use an active crossover now. Looks like PE has premade 2 way Xovers.

 

[keep_hope_alive Premium Member]

PE does have pre-made crossovers. just take note of impedance. you may want the single in-line 12dB/oct versions in lieu of a premade 2-way so you can run 4 ohm speakers.

the biggest challenge is locating these speakers since they don't have the same mounting as car audio products. they don't come with the same mounting rings and adapters. you end up fabricating.

 

[mustang90]

PE does have pre-made crossovers. just take note of impedance. you may want the single in-line 12dB/oct versions in lieu of a premade 2-way so you can run 4 ohm speakers.
the biggest challenge is locating these speakers since they don't have the same mounting as car audio products. they don't come with the same mounting rings and adapters. you end up fabricating.

A subwoofer will now be incorporated into the mix of this system. A 8" driver is not set in stone now. I'll be making a baffle board of sorts not much larger than what the drivers can fit into. It will in turn cover an empty compartment that will somewhat act as an enclosure. What are the +/-'s of using a 8" driver for mids rather than a 6" driver? Or vice/versa?

 

[keep_hope_alive Premium Member]

depends on the driver. some 8's are better at midrange than some 6's. some 6's are better at midbass than some 8's. you cannot compare speakers by size but by build quality and design.

all else equal, an 8" will play lower than a comparable 6" but since a 6" starts beaming later than an 8" it is more suitable for off-axis mounting in a door and due to coil inductance an 6" will play higher than a comparable 8".

but you can buy full range 8" drivers from Fostex or Dayton Audio that could be the only drivers in the system besides subs.