18" or 2x15" for OB

[barackuda]

Hi all. i was just wondering if there is a suitable driver for OB except the ALPHA 15A.More like some 18" that wont ruin my bank account.any ideas? i've searched the forum, but no luck.

this is just a thought, till now i stick to the ALPHAs.

danny

[mashaffer]

Dayton Quatro 15" DVC sub with one voice coil open.
Dayton IB sub
Eminence Beta15A (may need some EQ)
Selenium 15PW3-SLF
Pyle PPA15
Goldwood Monterey Series 18" (moderate Q but good xmax for 18")
Goldwood Huntington Series 15 or 18. (18 has very high Q so would want pretty small baffle most likely.


All from Parts Express and reasonably priced.

mike

[ScottG]

Ideally for an OB without electrical "eq" - you'll want an fs that isn't to low in freq. AND a Qts value around .7.

Think of it more as a midbass driver.

At a moderately low price I'd choose the Selenium (4 of them - 2 per loudspeaker):

http://www.partsexpress.com/pe/showd...number=264-338

[chops]

Originally posted by ScottG
Ideally for an OB without electrical "eq" - you'll want an fs that isn't to low in freq. AND a Qts value around .7.

Think of it more as a midbass driver.

How do you figure?

If it's bass you want from an OB, which I'm assuming the OP does since he's also looking for 18" driver options, then you would want/need a lower Fs.

A higher Fs will mean that you NEED electrical EQ to make up where the driver leaves off.

However, I do agree with the Qts value. You may not want to go too high on the Qts though (I'd say no more than a max of 1.0) since some say it can cause the bass to get a little flappy and uncontrolled.


Do take a good look at the Pyle Pro PPA15 drivers as they are a very prime choice for OB use.

If you want to go the 18" route, consider the Goldwood GW-1858 as it also has great specs for OB use (Fs: 30Hz and Qts: 1.07). Yes, the Qts is a bit on the high side, but with a good, solid amp with a high damping factor of 500 or so, you should be fine.

[ScottG]

Originally posted by chops



How do you figure?

If it's bass you want from an OB, which I'm assuming the OP does since he's also looking for 18" driver options, then you would want/need a lower Fs.

A higher Fs will mean that you NEED electrical EQ to make up where the driver leaves off.

As Fs decreases - so does the demand for increased excursion, resulting in increased distortion.

A higher Fs does NOT "mean that you need electrical EQ to make up where the driver leaves off", rather it means that you will need a sub-bass solution that typically is NOT open baffle (i.e. a monopole subwoofer).

Moreover a driver with a higher Fs has a better chance of summing flat in-room with a simple/cheap (and appropriate value) iron core inductor in series with the drivers.

The Pyle Pro (while less expensive) has a lower fs - and it will have higher excursion levels (recording dependent). It also is considerably less efficient than the Selenium, which tends to coincide with a much less detailed & "dynamic" presentation.

[jnb]

barackuda, could you post whether you intend to EQ (not just the sub bass but the dipole effect) as this affects the choice of driver. If you are going to EQ then there is no point in choosing a high Q driver and you have more options.

[ttan98]

Hi,

Head off to M. King's website for a new article on a
2 way OB.

http://www.quarter-wave.com/General/..._Articles.html

The first article, I think it is worth reading.

cheers....

[ScottG]

I'll add in a few other comments here..

2x15" has some extra benefits:

1. the net sd is larger than a single 18". Larger sd results in less excursion (which again results in less distortion).

2. "combing" will occur at higher freq.s with such a large sd 2 driver design - nulling out the drivers higher freq.s, most notably where any large driver will experience "break-up". Basically its a free "broad q notch" filter just where you need it provided your listening distance is far enough away from the drivers.

3. 2 drivers (..particularly vertically aligned, directly adjacent, positioned next to the floor), will load the floor better, (more uniform), than a single driver.

[barackuda]

hi guys
allready sorted - 4 Alpha 15" ordered yesterday.and next month DCX on the program, so it wil be Eq'ed.a lot
i went the well known route.now im using only 2 8" fullranges, and i get decent amount of bass with some eq on teh amp.realy surprised how much can you get out of small driver with reasonable volume.
anyway, ill be posting more as work continues.
thanks to all of you

i've only considerred the 18" just because of simlycity of construction, and i do know you can get stupid bass and loudnes from them they using 16 of them in a disco in my town crazy, sexy, marvelous



P.S.: where to get behringer dcx in UK?