3-way Speaker design with Bohlender Neo10

[Zippy2000]

Hi all,

First post here and I am still a noob, so please be gentle

I am planning to build a set of 3-way speakers to finally upgrade my home audio installation to something more decent, and I was hoping to get some advice on the choices I've made so far.

My driver choice:

Dayton Audio PT2C-8 Planar Tweeter - Freq range: 2khz - 26khz
____
Crossover 3khz
____
Bohlender Graebener Neo10 Planar Transducer - Freq range: 150hz - 6khz
____
Crossover 350hz
____
Dayton Audio RSS315HF-4 12" Subwoofer - Freq range: 23hz - 1kz

The plan is to cross the above three over using a DBX Driverack PA+ active crossover / audio processor, which can handle stereo 3-way and has a build in parametric equalizer for correcting some curves if needed.

The reason for choosing the above configuration is based both on people raving about the quality of the drivers, and I really like the looks of the Bohlender and the Dayton Audio 12" sub


I think the Neo10 and the Dayton tweeter can compliment each other very well, my worries lie more with crossing over the Sub with the Neo10, and this is where I was hoping to get some input from you guys. I am afraid that crossing over the sub at too high frequencies might destroy some of the quality in the lower frequencies, since most applications cross this sub over at 150hz or less...

The sub will be put in a ~3 ft3 enclosure (with bracing, speaker and port already subtracted), vented with a 4" port with a length of 15" to tune the enclosure to 25hz. The hole configuration will look like something like this:



Please shoot with comments / suggestions / improvements!

[GranteedEV]

Re: 3-way Speaker design with Bohlender Neo10

not liking the driver layout. push the midrange down near the woofer and put the twerter above it.

the rss315 should work up high enough but make sure to keep an eye on its aluminum cone breakup mode. try to keep that 40db down in level.

[Zippy2000]

Re: 3-way Speaker design with Bohlender Neo10

not liking the driver layout. push the midrange down near the woofer and put the twerter above it.

the rss315 should work up high enough but make sure to keep an eye on its aluminum cone breakup mode. try to keep that 40db down in level.

Not liking the layout aesthetically or will this layout cause interference of some sort?

The reason for having it like in the picture above is because it simplifies the internal layout, keeping the sub enclosure rectangular. I can move the mid down, but this means it will eat volume away from the sub and changes the internal shape of the enclosure.

This brings up another question: is the internal shape of an enclosure relevant, or is the volume more important?

[dthomas]

Re: 3-way Speaker design with Bohlender Neo10

Not liking the layout aesthetically or will this layout cause interference of some sort?

The reason for having it like in the picture above is because it simplifies the internal layout, keeping the sub enclosure rectangular. I can move the mid down, but this means it will eat volume away from the sub and changes the internal shape of the enclosure.

This brings up another question: is the internal shape of an enclosure relevant, or is the volume more important?

It will cause interference as you move horizontally in front of the speaker. Plus the dayton planar would not be my choice to go with those other drivers. I would consider the BG Neo3 I know it is more expensive but I think you will find it far superior and more in line with the quality of your other driver choices.

[lunchmoney]

Re: 3-way Speaker design with Bohlender Neo10

This brings up another question: is the internal shape of an enclosure relevant, or is the volume more important?

Volume far more relevant than shape... the shape of said volume almost doesn't matter, unless you start getting into long narrow shapes, like a pipe organ pipe or something... in your case it doesn't matter.

Listen to what these guys are saying about driver layout. Quite critical.

[Zippy2000]

Re: 3-way Speaker design with Bohlender Neo10

It will cause interference as you move horizontally in front of the speaker. Plus the dayton planar would not be my choice to go with those other drivers. I would consider the BG Neo3 I know it is more expensive but I think you will find it far superior and more in line with the quality of your other driver choices.

Good point there. Stacking the drivers will make the whole unit look quite tall to my opinion. What about rotating the Neo10 with 90 degrees, so that it is positioned horizontally? Not sure whether this unit was designed to spray the sound perpendicular to it's length, or is this not even possible to design in a speaker?

The Dayton planars are unfortunately already ordered and are currently shipping towards Norway... Might be able to use them in a different project though ;)

[dthomas]

Re: 3-way Speaker design with Bohlender Neo10

Good point there. Stacking the drivers will make the whole unit look quite tall to my opinion. What about rotating the Neo10 with 90 degrees, so that it is positioned horizontally? Not sure whether this unit was designed to spray the sound perpendicular to it's length, or is this not even possible to design in a speaker?

The Dayton planars are unfortunately already ordered and are currently shipping towards Norway... Might be able to use them in a different project though ;)

First nothing wrong with the Dayton Planars.

You probably can't rotate the Neo10, typically the vertical dispersion pattern on planars is limited compared to the horizontal dispersion pattern. So If you rotated them 90 degrees they would beam straight forward and have very limited response in the horizontal axis. These type of speakers don't radiate the same as a round cone or dome. I have not measured the Neo10 yet but I suspect they are meant to be oriented just as you have them and turning them might be a bad thing.

[dthomas]

Re: 3-way Speaker design with Bohlender Neo10

First I would make sure the planar tweeter is about ear height or 35 to 36" from the floor. So not sure how tall your cabinet is. You could push your woofer down and port them on the side or the rear. This should give you room to stack the mid and tweeter.

[kmibb]

Re: 3-way Speaker design with Bohlender Neo10

If the Neo10 actually can cross as low as 150Hz, you'd probably be fine side-firing the sub. Maybe do a passive radiator setup.

[kmibb]

Re: 3-way Speaker design with Bohlender Neo10

If not, I'd ship the Neo10 and Dayton planar back and get the Neo3 and Neo8. The RSS315 is capable of playing up to 3-400Hz (see Pete S.'s Byzantiums,) which should be high enough for a Neo8.

[dthomas]

Re: 3-way Speaker design with Bohlender Neo10

If the Neo10 actually can cross as low as 150Hz, you'd probably be fine side-firing the sub. Maybe do a passive radiator setup.

That's a great idea.... side fire the sub. Opens up the opportunity to narrow the cabinet a bit also.

[Zippy2000]

Re: 3-way Speaker design with Bohlender Neo10

First I would make sure the planar tweeter is about ear height or 35 to 36" from the floor. So not sure how tall your cabinet is. You could push your woofer down and port them on the side or the rear. This should give you room to stack the mid and tweeter.

The max height of the cabinet has to be around 40" which is a little bit dictated by where the cabinets will be placed in the living room, but this seems to fall within the sitting position ear height you indicate above.
Placing the port on the side is something I haven't thought of yet, but definitely solves the vertical spacing problem. Thanks for the good suggestion!

Just one last question with respect to placing things next to each other: will placing the port tube next to the mid or high also create interference? Not sure why I would want to put the port next to either of those, but in the case that it might have an aesthetically appealing look...

I will post a picture soon of some remodelling.

[dthomas]

Re: 3-way Speaker design with Bohlender Neo10

The max height of the cabinet has to be around 40" which is a little bit dictated by where the cabinets will be placed in the living room, but this seems to fall within the sitting position ear height you indicate above.
Placing the port on the side is something I haven't thought of yet, but definitely solves the vertical spacing problem. Thanks for the good suggestion!

Just one last question with respect to placing things next to each other: will placing the port tube next to the mid or high also create interference? Not sure why I would want to put the port next to either of those, but in the case that it might have an aesthetically appealing look...

I will post a picture soon of some remodelling.

No the frequencies coming from the port are already so long (wavelength wise) that placement is not that big of a deal. And since you are crossing the woofer low to the Neo10 there won't be a lot of midrange issues that might escape the port tube. Assuming a low tuning the port can go on the sides the back or even the top if you wanted to. If you put it on the back you need to allow distance between the terminus and the wall equal to the inside diameter of the port.

[Mayhem13]

Re: 3-way Speaker design with Bohlender Neo10

First, you'll need a long port to get a low enough tune in that size box, so build a plinth and downfire the port. That will allow you to get the woofer closer to the floor and save the need for full baffle step compensation.

You can run the Dayton to 250 hz with a steep filter....I've done it as per a recommendation from Pete S. and it sounds great.

Return the Dayton planers and get the Neo3. Run the Neo 10 and 3 open baffle. Your ears will love you for it.

[djkest]

Re: 3-way Speaker design with Bohlender Neo10

First, you'll need a long port to get a low enough tune in that size box, so build a plinth and downfire the port. That will allow you to get the woofer closer to the floor and save the need for full baffle step compensation.

You can run the Dayton to 250 hz with a steep filter....I've done it as per a recommendation from Pete S. and it sounds great.

Return the Dayton planers and get the Neo3. Run the Neo 10 and 3 open baffle. Your ears will love you for it.

That sounds pretty awesome. You'd have the open baffle mids and then a dedicated "box" for the subwoofer. Downfiring doesn't seem like a bad idea, that will probably give you the most length. I have this subwoofer driver and it's quite awesome for music and the build quality is top notch!