Passive way to maximize Dayton ND91 3.5" full range bass?

[CZ Eddie]

I'm going to be using the Dayton ND91 3.5" 4ohm speaker in a portable bluetooth setup.

Dayton Audio ND91-4 3-1/2" Aluminum Cone Full-Range Driver 4 Ohm

Since I want as small as possible an enclosure, I've decided to go with PartsExpress' recommended .01 cu.ft. sealed enclosure.
Now, when I model this in WinISD using 33 watts (about what I have available), I have tons of room left over before hitting the rated 4.6mm x-max "limit".
So I'm thinking I'd like to tweak it just a bit for a bit more bass down below.

You can see in my screenshot the first two WinISD pictures are without any bass-boost.
The third is with 3db added to 80hz.
Some quick Googling shows you cannot passively add "bass boost".
But you CAN attenuate, say, all the frequencies above 80hz.

So, I'm hoping someone can suggest what to do next to get what I want?

I also added the WinISD file in case anyone wants to model on their own.

 

[Andrew Eckhardt]

You might use a shelving 12dB oct low pass filter, just barely possible passively with reasonable parts if your amplifier input impedance is high enough. Check PLLXO.

 

[freddi]

depending upon circumstances, you might be able to get a bit more with a series capacitor - when doable, that will alter system impedance around resonance, lowering Z with more power into the speaker and more excursion in that area. (this may not work with low feedback tube amps)

 

[Jerms]

Ummmmm....

If it's anything like the ND90 or the Aurasound NS3 bass production should not be an issue. (for a 3" driver....)

Go vented IMO. Play with the settings in WinISD. You should be able to get it down to say 60hz.

J.

 

[CZ Eddie]

...Aurasound NS3 .....

Aww, crap.
I just remembered, I ordered the NS3 instead of the ND91.
Now I've got to re-do all my everything.

 

[Jerms]

Aww, crap.
I just remembered, I ordered the NS3 instead of the ND91.
Now I've got to re-do all my everything.

Same advice, go vented for bass. Enclosure is 3x the size but it's worth it.

 

[sreten]

Hi,

The NS3 is not as vented friendly as the ND91.
Small as possible = sealed, and the NS3 with
a Qts of 0.67 (versus 0.41) screams sealed.

rgds, sreten.

 

[Jerms]

Sealed you can run it in 2 litres..... erm.... 8x4x4 inches internal dimensions down to about 100-105hz. A bigger box gets you more bass down to say 85hz in 6 litres.

Vented you need 6 litres but it can be tuned for bass to 50hz.

I ran it through WinISD. Grabbed the driver "WDR" file from this forum.
Incidentally, you could get the newer WinISD?
WinISD - Linearteam

J.

 

[CZ Eddie]

Thanks, folks.
I did not realize a newer WinISD was out.
I'm on 0.50 and the link above shows an 0.7xxxx available. I'll check it out!

I'm building a vented 0.30 cubic foot enclosure tuned to 75hz.
Should be done by tomorrow.
Here it is modeled vs. the same size 0.30 sealed enclosure.
Added a high pass to the vented. Sealed didn't get one.

It's looking like I won't need any passive attenuation.

 

[Jerms]

Incidentally, I changed the Xmax in the WDR file I obtained. It should be 4.75mm. The wdr has it as 20mm! :O

 

[Jerms]

I tripped over this the other day.... It might help.
https://sites.google.com/site/undefinition/sprite

J.

 

[CZ Eddie]

That IS helpful, thank you!
I'm having some issues making port holes with my old, dulled out bit. Going to change my strategy today.