[G3]

I have been reading, and reading, and reading for over a year now.  It's time to put up or shut, order some parts, make some mistakes and get my hands dirty.

I need help choosing the low end drivers. I am smart enough to know that I dont know what I dont know, so please educate me on the things that have not considered.

What I like---I fell in love with Pure Audio Project trio 15 horn and the Spatial M3 at the  Ca Audio sgow last year. The family budget says there are on too many 0's in the price tag.


What I want--- An open baffle that will get close enough to 30hz for classic rock and hip hop low end, with a sound stage that lets me close my eyes and touch Ms Nina Simon.


What I have--- An assortment of amps including a Carver 500t to throw at the low end , 1 pair of Heil tweeters plus $600 and not a penny more.


My Space ----  25ft*24ft  with two sliding glass doors (left wall and far rear wall).  I would like to keep the dimensions(60in*23in) close to the Magnapan MG 1 that I already have. Wife has already agreed to that size, why temp fate. 




Shopping list----
Mids. Dayton Audio RS225P-4A 8" Reference Paper Woofer 4 Ohm  Part # 295-567  $55*2

Dsp - Dayton Audio DSP-408 4x8 DSP Digital Signal Processor. Part #260-500. $149

Microphone --Dayton Audio DSP-408 4x8 DSP Digital Signal Processor Part #390 808. $75

Sub total $334    leaves me $164 for the low end.


Woofer options

1)Alpha 15a 1per speaker Part #290-407. $75*2 = $150
2)GRS 15PF-8 15" Paper Cone 2 per speaker  Part #292-415. $25 * 4. =$100
    Fs 29. Qts 1.39.   Sen 87db
3)Goldwood GW-215/40/8 15" 1 per speaker Part # 290-346 $47 * 2 =$104
     Fs 30.5   Qts1.09  Sen 89.6db
4)GRS 12SW-4 12" 2 per speaker Part # 292-484 $20 * 4 =$80
     Fs 29.6   Qts98  Sen 88db


Help me not purchase the wrong drivers.

[matevana]

I'd like to suggest something a little different, based mostly on your musical tastes.

First, check your math. If you're starting with a max budget of $600, you should have $266 remaining for the low-end, (not $164) based on your numbers.

I'd take a look at a single Morel Ultimate UW 1058.  There's currently an open box option at PE for $260. It's probably one of the best sounding low bass drivers I've ever worked with. Put it in a small sealed box (cough) and it can likely be hidden in your listening room. Let the Dayton 8" drivers roll off naturally on the low end, and use the sub to fill in below that. Your DSP will get you there. I have spent a lot of time messing with OB subs, and unless you are willing to spend a lot more (servo subs or multiple high quality drivers) you will probably not be satisfied given your musical selections.

Just a thought.

[JCarney]

Hi G3,
Listen to matevana. If you do a search with his name on here, you will find multiple ob builds that matevana has posted pics and details. I do believe the man knows what he is talking about, and you would be well served heeding any advice or help he is willing to share, which is a lot from what I have seen.

Best of luck with your build, and have fun, and keep us posted please.

JCarney

[AJinFLA]

What I want--- An open baffle that will get close enough to 30hz for classic rock and hip hop low end, with a sound stage that lets me close my eyes and touch Ms Nina Simon.
What I have--- An assortment of amps including a Carver 500t to throw at the low end , 1 pair of Heil tweeters plus $600

Shopping list----
Mids. Dayton Audio RS225P-4A 8" Reference Paper Woofer 4 Ohm  Part # 295-567  $55*2


4)GRS 12SW-4 12" 2 per speaker Part # 292-484 $20 * 4 =$80
     Fs 29.6   Qts98  Sen 88db

I would definitely go with the GRS 12SW x4 at bottom from that list (i think I posted a measurement here once), they have more than double the xmax of the other weak motor drivers, which creates issues of itself.
If the Heil is the big one, I think that can be crossed as low as 1k. I would consider a smaller mid, maybe 5-7". With proper shaping around it/narrowed baffle, you will get better dipolar polars/off axis, which certainly contribute to the perceived timbre in room.

cheers,

AJ

[fdandrews]

I have the Alpha 15a woofers and have used them in a 24" square by 7" deep U-frame. I also have MCM 21" woofers that I used in the same baffles. The most recent speakers in those baffles are Selenium 1509 15" woofers, which sound the best of the three in my setup, despite having a lower than recommended Qts. The Alpha 15s were just OK, a bit muddy and bottomed out regularly due to low x-max. Surprisingly, the MCM 21" woofs also bottomed out, even though I don't listen very loud. The suggestion to go with 4 woofers is good advice, based upon my experience. With open baffle, more speaker surface area and x-max are a good thing. I have heard the Pure Audio Project speakers with (4) Morel 10" woofers, and with (2) 15" woofers, which I believe are Eminence Deltalite, and agree that they are great sounding speakers. 

[lowtech]

The OP may want to read some objective feedback on the Dayton DSP-408 here.  It may not currently be ready for prime time.