Onkyo 4" mini OB arrays

[valleyman]

I just saw these little Onkyo 4" drivers on madisound for next to nothing:

http://www.madisound.com/catalog/pro...roducts_id=727

I have never heard a pair of open baffles, so thought it might be an opportunity to throw together a very cheap pair just for the experience.
I was thinking about using 4 per speaker.

I have no real experience with OB speakers or line arrays but a glance at the params indicated they might work ok.

Could someone let me know what kind of baffle size I'd be looking at?

They also have a fairly huge response bump around 2.5kHz (and 9.5kHz actually). Could a couple of passive components help even this out?

I'd like to keep them reasonably small and obviously I have no illusions of getting any real bass out of these.

Many thanks for any help offered.

[woody]

$3.50 each isn't my idea of next to nothing. Now if they had realy
had them for $.75 that might be different. But that 8" full range
Pioneer speaker at ~$20 might realy be a better bet.

[valleyman]

Wouldn't an 8" driver need a pretty huge baffle if I want open? $3.50 is what I consider next to nothing. I can put 4 in each speaker and including wood have a pair built for $40... I consider that worth it for the experience of hearing a pair of OB arrays.

Bear in mind also I'm from the UK. £20 here buys you a couple of days food

[preiter]

Originally posted by valleyman
I just saw these little Onkyo 4" drivers on madisound for next to nothing:

http://www.madisound.com/catalog/pro...roducts_id=727

I have never heard a pair of open baffles, so thought it might be an opportunity to throw together a very cheap pair just for the experience.
I was thinking about using 4 per speaker.

I have no real experience with OB speakers or line arrays but a glance at the params indicated they might work ok.

Could someone let me know what kind of baffle size I'd be looking at?

They also have a fairly huge response bump around 2.5kHz (and 9.5kHz actually). Could a couple of passive components help even this out?

I'd like to keep them reasonably small and obviously I have no illusions of getting any real bass out of these.

Many thanks for any help offered.

Baffle size is independent of the driver used, it determines the low end response of the speakers. You can read about it here:

http://www.linkwitzlab.com/frontiers.htm#B

Those drivers look ok, so long as you are pairing these OB speakers with a subwoofer or some bass helper drivers.

[Kensai]

I had the B20s on 18"x12" baffles for the longest time. Some EQ, and they were good to 50-ish. You could probably get the same from reasonably sized floorstanding baffles without the EQ, or good response into the low/mid 40s with both.

The Onkyos are really too large to make a straight, fullrange array. The center to center spacing it too great, so you will get combing at some point, and the Fs of 96 and only moderate Qts will combine with a narrow baffle to have you start rolling off probably at 120Hz, in room. With multiple drivers, it will probably respond well to EQ, but you're not likely to get anything of value below 80Hz if that low at all.

Kensai

[adason]

those two ugly bumps are hard to deal with
I would suggest to use them as midranges and have a tweeter in the middle of an array
than might solve bumps and comb effect
just choose tweeter with proper efficiency
it will be still line array, just better

[valleyman]

The aim here isnt really to end up with a pair of speakers I'll really use, more just to hear what open baffles sound like.

Am I completely wasting my time just throwing 4 of these onto a baffle say a foot wide by a foot and a half tall? Could make them a bit bigger if necessary

The way I see it I'll end up with some speakers to listen to and then probably just a load of drivers for testing amps. I usually manage to kill one or 2 in the process of building an amp...

[adason]

more just to hear what open baffles sound like

you might as well built it right, how else you would hear how it sounds like
even you do not plan on using it forever

how wide the baffle should be depends how low you want to go
there is a graph circulating here many times over, the repationship on open baffle size and start of low fr rolloff

those 4" speakers will not go too low no matter how wide the baffle

[adason]

here it is

[gainphile]

They will simply be too small except for midrange only

OB requires big drivers with high Qts. I would start with 12" with Qts 0.9 and above for passive.