[bartwuster]

Hi everybody,

Currently I'm in the process of sourcing parts for my first open baffle project, and as I'm not from US, shipping from Parts Express to me is quite expensive, so I have to buy from local.

I found one seller selling the Eminence Delta 15A, do you guys think I can use it as my woofer?
I'm thinking of using H-Frame subwoofer, and on top will be using 8 inch fullrange driver from Aurel Bryan, from Indonesia.

I'll be using Behringer CX2310 for low pass to the H-frame, and planning on driving the fullrange driver full without any crossover, so I'm gonna use one stereo amp for fullrange and another stereo amp for the H-frame sub.

Really appreciate all of your help, especially on the use of Delta 15A as woofer.

Regards.

[richidoo]

Delta 15A is a great driver. But the Qts is only .53, a little lower than the .7 that is ideal for a OB bass drivers that are not using any electronic EQ (like passive XO.) I prefer a little bit lower Qts driver for OB bass, as that means there is more control of the cone and that means better bass detail. But it also means you don't get flat extension to 30Hz  with no boost like you would with a speaker with Qts .7. You just need to boost the bass a little as it goes into the low frequencies.

Since you are designing an active speaker, you can compensate for the early roll off of the Delta15 by applying a little bass boost EQ via the crossover.

But the Behringer CX2310 does not have any EQ features. All it does is the Linkwitz Riley 24 crossover filters, and level control. I would recommend you choose a different crossover device that allows EQ adjustments to the bass driver, that is pretty important with OB, since there is usually a fair bit of adjustments and compensations needed with OB that are not needed with box speakers, for which this Behringer is intended. Many bass amps have DSP or analog EQ filters built in.

If you use a xo box like this Behringer, or something else of similar low cost, be aware that it is suitable for use with the bass driver only. You can't use it as a full crossover between the sub and the full range driver because the signal to the full range driver will sound very rough because of the poor quality parts and circuit design choices in this category of low cost pro audio gear. You have the right idea running the FR driver full range, and fine tuning the bass driver to complement it, but you will need some EQ adjustability in the low pass filter device to allow you to achieve flat FR with the free running full range driver.

You might also benefit from adding a passive series capacitor to the full range driver to steepen it's natural rolloff slope a little, to make it easier to blend with the sub in frequency response and phase response. A good quality cap will not take anything away from the full range driver.
Good luck!

[bartwuster]

Hi richidoo,

Thanks for the reply, really appreciate it.
In your opinion, would it better for me to try to source the Alpha 15A, or maintain with Delta 15A and look for something like Behringer DCX2496 for the crossover device? I think DCX2496 got EQ adjustment function. Or do you have any recommendation for the crossover device that's priced not as high as DCX2496?

Or, what do you think if I'm using the Yung SD100 plate amp with 6bd boost at 45hz for the woofer? It got 6db boost, phase and cut off level frequency, but I don't know if the 6db boost can help with the EQ function as per your comment.

I'm using Harbeth M30.1 now and although it's a very good speaker (for me), I'm almost confirm to let it go now to venture into this open baffle project.

[mkane]

 Yout location if it's close I have a Rolls SX45 2 way you can have for the cost of shipping

[richidoo]

hey bart
higher Q bass driver could eliminate the need for any bass boost. Alpha is very high Q, that's why it's so popular with OB experimenters. I think it's too high Q, but many people like it. Beta 15 is Q .58, that should get you down to ~40Hz without EQ. Delta is Q.52, maybe <50Hz without boost on 18" baffle. Delta costs more because it has stronger motor to control the cone better and make more detail. Just depends what your sonic preferences.

The DCX is popular xo box. I have one with modded analog output. The analog inputs sound bad, and it's not very reliable, the digital input receiver chip fails often. But it's relatively cheap for DSP crossover and the concept and user interface is excellent. You'll need XLR>RCA adapters to connect to consumer gear. When using the digital input it sounds OK enough to use on the full range driver too - as long as you're not a golden-ear type. I'm not recommending it as I am not a big fan of it, but I recognize that it serves a useful purpose.

If you use a computer for your music source, then you can do the bass boost for the Delta driver inside the music player software, that would allow the use of the Behringer CX2310 for the low pass on the Delta 15 playing down to 30Hz. But having a computer in the music system is two edged sword. It can sound very nice, but it can be fussy just when you rather listen to music.

The Yung SD100 doesn't have any EQ controls. I think a regular stereo amp for the bass, like your original plan is a better value.

If you can build DIY electronics, you can make an inepensive and very good sounding low pass filter and also EQ for your subs, using information and PCBs from Rod Elliot website.

[bartwuster]

Yout location if it's close I have a Rolls SX45 2 way you can have for the cost of shipping

Hi mkane,
That's a very generous offer from you, but I live in Malaysia and I assume you live quite far away sir..

[bartwuster]

hey bart
higher Q bass driver could eliminate the need for any bass boost. Alpha is very high Q, that's why it's so popular with OB experimenters. I think it's too high Q, but many people like it. Beta 15 is Q .58, that should get you down to ~40Hz without EQ. Delta is Q.52, maybe <50Hz without boost on 18" baffle. Delta costs more because it has stronger motor to control the cone better and make more detail. Just depends what your sonic preferences.

The DCX is popular xo box. I have one with modded analog output. The analog inputs sound bad, and it's not very reliable, the digital input receiver chip fails often. But it's relatively cheap for DSP crossover and the concept and user interface is excellent. You'll need XLR>RCA adapters to connect to consumer gear. When using the digital input it sounds OK enough to use on the full range driver too - as long as you're not a golden-ear type. I'm not recommending it as I am not a big fan of it, but I recognize that it serves a useful purpose.

If you use a computer for your music source, then you can do the bass boost for the Delta driver inside the music player software, that would allow the use of the Behringer CX2310 for the low pass on the Delta 15 playing down to 30Hz. But having a computer in the music system is two edged sword. It can sound very nice, but it can be fussy just when you rather listen to music.

The Yung SD100 doesn't have any EQ controls. I think a regular stereo amp for the bass, like your original plan is a better value.

If you can build DIY electronics, you can make an inepensive and very good sounding low pass filter and also EQ for your subs, using information and PCBs from Rod Elliot website.

Hi richidoo,

Thanks for the reply. I think I can live with not so much bass and more detail is always welcome. I might proceed with Delta 15A but will definitely give it a deep thought first.

I'm listening music using laptop, but I'm not that good in DIY electronics, so I'll decide whether to go with cx2310 or DCX.

Will update with my decision then.

Thanks!

[mkane]

  I'm in CA, US. I can fit this in a medium flat rate box which is close to 20$. Not sure if these ships worldwide but I can check.

[mkane]

  Yes, it's expensive. Priority Mail International medium flat rate box is $74.95

[bartwuster]

 
But thank you for the offer mkane, that's very nice of you.

Mkane, your OB is not using H-frame subwoofer but slot loaded instead, right?
May I know is it your own design?

I know the initial design is from Nelson Pass but yours is quite different, and look awesome sir..

[mkane]

  Pass design also. The build was a quickie and when and if I'm satisfied I'll build another pair, taking my time and with Baltic Birch.



This pic is with AN 10 Classics. I'm also going to try Jordan Eikona-2's

[bartwuster]

  Pass design also. The build was a quickie and when and if I'm satisfied I'll build another pair, taking my time and with Baltic Birch.



This pic is with AN 10 Classics. I'm also going to try Jordan Eikona-2's

Nice mkane, I'll also look into this design as well.

[mkane]

  There sporting 1808's now.

Next week I'll give Jordans a try.

[bartwuster]

Nice!

Mkane, have you ever tried the h-frame sub config as well?
If yes, how do you compare it with the slot-loaded config?

[FullRangeMan]

Bart if you could use the PAP OBA15 Ferrite(it is a special Alpha15A $139/pair) you could not need correction or xover, if need you should use just a 4.7mH inductor (270Hz).

Your project will be more simple. Just a idea.
http://www.pureaudioproject.com/product/15inch-open-baffle-bass-woofers/

[mkane]

Nice!

Mkane, have you ever tried the h-frame sub config as well?
If yes, how do you compare it with the slot-loaded config?

 I have not. The first OB project the woofers were in the baffle. This is my second OB build. Bass is just right for the SLOB using Mini DSP HD.  I've never listened to anyone else's OB so I'm not sure how there suppose to sound.

[bartwuster]

Bart if you could use the PAP OBA15 Ferrite(it is a special Alpha15A $139/pair) you could not need correction or xover, if need you should use just a 4.7mH inductor (270Hz).

Your project will be more simple. Just a idea.
http://www.pureaudioproject.com/product/15inch-open-baffle-bass-woofers/

Hi FullRangeMan,

I've looked at the link given, it stated Euro139 and only available from Germany, I'll send them an email to ask about this.

When you said it's going to be more simple, I still need the fullrange driver right? And the configuration is as per PAP Trio 15 with two 15inch per side?

Basically my listening room is quite small, roughly 10ft x 11ft.

[bartwuster]

I have not. The first OB project the woofers were in the baffle. This is my second OB build. Bass is just right for the SLOB using Mini DSP HD.  I've never listened to anyone else's OB so I'm not sure how there suppose to sound.

Thanks for the reply mkane, I'm thinking of also using the miniDSP, but from my understanding, if I'm using it, the conversion will be done again inside the miniDSP so my current external DAC conversion is not being used.

[FullRangeMan]

Hi FullRangeMan,

I've looked at the link given, it stated Euro139 and only available from Germany, I'll send them an email to ask about this.

When you said it's going to be more simple, I still need the fullrange driver right? And the configuration is as per PAP Trio 15 with two 15inch per side?

Basically my listening room is quite small, roughly 10ft x 11ft.

It will be more simple in the xovers, it not need DSP corrections.
You yet will need the FR driver, avoid use 2 woofers if you have a small amp, it will lower impedance to 4 ohms level, unless you have a amp that run safely in 4 ohms, I dont had this luck.

Please note that PAP OBA15 sensitivity is 93dB already as OB, others Eminence drivers show SPL around 97dB or higher in a huge BR box.

[bartwuster]

It will be more simple in the xovers, it not need DSP corrections.
You yest will need the FR driver, avoid use 2 woofers if you have a small amp, it will lower impedance to 4 ohms level, unless you have a amp that run safely in 4 ohms, I dont had this luck.

Please note that PAP OBA15 sensitivity is 93dB already as OB, others Eminence drivers show SPL around 97dB or higher in a huge BR box.

Ok FullRangeMan, noted with thanks.