Speaker driver order

[Aurality]

Just in the process of building some open baffles a kind of variation of some Lampizator ones. I intend to make these three way to begin with,
but might experiment with 4 way down the line, so want to leave my options open. Supposing I did - could you forsee any problems in having a low mid, or bass (taking care of the kick drum frequencies) above the mid and tweeter and using the 18" volt for sub bass duties as presented in my photo. my instincts tell me it should be ok, but just thought I would check first before I start cutting. It can only work in this arrangement, because the tweeter is at ear height in this config, so can not go below it and since I am building 3 way first the mid needs to be next to it. Ignore the port on the front, long story, but won't be in the initial design - the 18" bass is an open backed box.

[cuibono]

what is the XO frequency between the low mid and the bass drivers? It is probably fine if below 200Hz.

Are you sure you want to use an 8" upper mid? it is going to beam like crazy above 1kHz. With a 4-way, you have the luxury of using each driver below it's beaming frequency...

[Aurality]

Thanks Cuibono,

Not really thought about the cross overs if I intend to go 4 way.
as for the 3 way design and cross over and reason for 8" mid
is I was following the design plans here,

Endorphine from Kingston Kitchen

do you think the upper mid should be bigger? or the low mid should match 8" also?

[the Interceptor]

I'd say the low mid is fine at 10", but the mid should be 6".

And you may get a problem with the directionality of the Raal ribbon. I don't know which model you're planning to use, but I know that it likely will beam vertically pretty badly and thus should either be at the height of your ears or at least point towards them.

[cuibono]

For OB designs, the choice between 3 way and 4 way makes a pretty big difference.

I wouldn't make the lower mid larger either - I'd do a 10" or 8" lower, and a 4" to 6" upper. An 8" is more plausible for mid if one were only using one driver, but I still think it is undesirable, due to irregularity of the polar response above 1kHz.

It seems like deciding on which drivers and how many ways would include estimating XO points, particularly for OB designs. But either way, you should be fine if you decide to put the 4th driver on top.

EDIT; and I agree with interceptor - you need to be very careful where you point that ribbon at!

[Aurality]

Thanks lads! The Raal I intend on using is the Raal 140-15d, and in the
photoshop mock up it is placed at ear height. At the moment (or soon)

I will have the:

Volt RV4504
Raal 140-15d
Saba Green cone 8"

This is my first attempt at speaker building so very clueless and naive.
I just want to have a great pair of speakers that are keepers and will
stay with me a long time. How would you lads go about this build?

Open and appreciative to to any suggestions.

Box is 180 litres open backed.

[Paul W]

The drawing looks like the RAAL is oriented horizontally? Assuming you want wider horizontal radiation than vertical, orientation SB vertical.

[Aurality]

Thanks Paul,

Told you I was clueless

You have just saved me some time and money, cheers.

[the Interceptor]

Since the 180l "box" is open backed, you will not need a port.

And prepare to fiddle with the details for a long time until it is perfect. The thing with first speakers is that you learn a lot, but in order to learn, you need to have it finished and running.

[Aurality]

Thanks interceptor. The port drawing was just there in case I do not like the
bass from the open backed box and decide to seal it off and go for reflex instead. Buut sticking with open backed box to begin with.

The reason I had an 8" mid Is because I was following the lampizator endorphin P17 project (link to project design including cross
over posted above) with the SABA green cones, but substituting the SABA tweeter for a RAAL, Since the consensus seems to be the 8"
is not the best way forward. can anyone recommend a 6" Mid to take place of the 8" SABA?