Suggest me a layout pls.

[Arty]

Well usualy i do not encounter this kindof problem, but here it goes.
I recently purchased a pair of more or less acceptible midbass drivers from a very small company.
The problem is, the drivers feel good in approx 22 liters and 37hz tuning.
And thats where the problems start.
The port would be -so to say- very long.
If it was for subwoofer use i would find a way to place it.
But i intend to make this a 2-way speaker.
The data for the driver:
Name: 17R634A
Fs = 34,54 Hz
Qms = 2,366
Vas = 31,86 liters
Cms = 1,249 mm/N
Mms = 17, g
Rms = 1,559 kg/s
Xlin = 7, mm
Xmax = 9, mm
Xmech = 15, mm
Sd = 134, sq.cm
Qes = 0,432
Re = 5,2 ohms
Z = 8, ohms
BL = 6,664 Tm
Qts = 0,365
2.83-V SPL = 88,68 dB

It is 175mm diameter (build in diameter)

I never made a 2 way with the port firing upward, what you people think about that solution ? seems a bit odd.
Or i could make it fire downwards, and lift the whole box from the ground by cca. 1 port diameter, witch still is a little bit odd.


I'v attached its on-axis response, not looking that bad at all.
http://www.audionl.hu/oscommerce/cat...X25TG05-04.pdf
supposedly this tweeter is what i found affordable and planning to use it with the chepoo woofer.
not yet sure about x-over freqvency, will see that later.
So the main problem now if finding a box aligment that can hold all this "stuff".

Thank You for the feedback.

[RockLeeEV]

Consider modeling it by adding a pair of PRs on either side, instead of a long vent.

For example in 1.4 cu ft, 2X Dayton SD215-PR

[dumptruck]

What kind of cabinet dimensions are you thinking? You could do a slot port, potentially only on one cabinet side (making it relatively easy to adjust).

[sreten]

undefinition (see FAQs)
Zaph|Audio
FRD Consortium tools guide
Hi,

I cannot see the problem. 37Hz vent tuning in a 22L box is easily done.
Using flared poets will considerably shorten any needed ports.
The are usually placed on the rear of a deeper than wider box.

A suitable flared port with 50mm internal diameter is around 160mm long.

rgds, sreten.

Note the bass/mid response will be nothing like that curve in the box, see links below :

Designing Crossovers with Software Only
RJB Audio Projects
Jay's DIY Loudspeaker Projects
Speaker Design Works
HTGuide Forum - A Guide to HTguide.com Completed Speaker Designs.
DIY Loudspeaker Projects Troels Gravesen
Humble Homemade Hifi
Quarter Wavelength Loudspeaker Design
The Frugal-Horns Site -- High Performance, Low Cost DIY Horn Designs
Linkwitz Lab - Loudspeaker Design
Music and Design

Great free SPICE Emulator : SPICE-Based Analog Simulation Program - TINA-TI - TI Tool Folder

[Tytte71]

Don't know your design limits here, but when simulating the driver in a net 30l BR cabinet, using a 30cm^2 port tuned at 28Hz, I end up with a port lenght of about 33cm. That's not very long, or?
FR rolls very gently off from about 100Hz and is 4dB down at about 28Hz. Below 28Hz it FR falls quickly off-cource - down 14dB at 20Hz.
Adding room gain could give a nice lift in the lower region. Speakers could be placed relatively close to the back wall.
Max output ~100dB@100Hz@25W - baffle step (within linear stroke)
Impuls response looks okay. Just a very mild port resonance at ~470Hz. Looks all right to me

Edit: Sorry sreten didn't see you - was in editing state of mind when you answered

[bjorno]

Originally Posted by Tytte71

Don't know your design limits here, but when simulating the driver in a net 30l BR cabinet, using a 30cm^2 port tuned at 28Hz, I end up with a port lenght of about 33cm... Looks all right to me

Hi, Agree, I came up with a very similar suggestion:

b

[Tytte71]

Originally Posted by bjorno

Hi, Agree, I came up with a very similar suggestion:

b

What tool is that bjorno?
Edit: ... I see it, silly me didn't notice it was possible to zoom the picture twice :S

[dumptruck]

Originally Posted by sreten

<for tuning in OP> A suitable flared port with 50mm internal diameter is around 160mm long.

Except that's up around 34m/s airspeed at 50W, which is a little high. If you want to stay down at 17m/s, you need more cross section and thus more length. 2x20x35cm, for example. Still doable, either way.

[Arty]

true 30 cm is not that long.
but i would like to stick to a design that is slimm and high.

hence the only possbile way to fit a port would be top or bottom.
quaetion is how would that affect tuning -i do have some clue it would require shorter port is it was firing downwards- , and more importantly how would it work out? For subwoofers i do know it is no problem, but does the same is true for this case, where this should be a 2-way design?

[Tytte71]

Originally Posted by Arty

true 30 cm is not that long.
but i would like to stick to a design that is slimm and high.

hence the only possbile way to fit a port would be top or bottom.
quaetion is how would that affect tuning -i do have some clue it would require shorter port is it was firing downwards- , and more importantly how would it work out? For subwoofers i do know it is no problem, but does the same is true for this case, where this should be a 2-way design?

Let's say you want a cabinet that's 95cm to the centre of the tweeter, the midwoofer mounted just below it and you want to limit the baffle width to 180mm.
Near the bottom of the baffle, or back, there is plenty of space for the port opening. The port would then go straight in and bend 90deg. upwards until its total length is equal to the tuning frequency. Have I missed your question?
Regarding port opening at the top or bottom, there is very little difference between this two-way design and a subwoofer. The port tuning frequencies are in both cases "sub" frequencies.
I would however not place the opening on top since dust and other stuff will collect through it. You need some clearance to the floor when having the port opening in the bottom of the cabinet. You could use adjustable feets to fine tune for your taste
Cheers