Small cabinet with a good sound?

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Hi!


I'm struggling to finish this speaker project.

My initial plan was to make a cabinet of internal 1L volume (for 2 full range drivers*), but that doesn't seem very promising.
*I'm running two 2" Funtek fr58ex drivers.

Since then I've read a lot of advices to split the chambers inside for the individual drivers, what's your oppinion on this?

I've made a, (music gods) please excuse me, cardboard cabinet with 1L internal volume, with the two drivers sharnig the whole 1L, and a 4"x1" flared tune port.
I was surprised it produced any sound at all, but it's very weird and tiny, is it the cardboard itself or is it a wrong port lenght/width, or just a small internal space??

I'm planning on rebuilding it with some quality MDF, would 6mm thickness be enough?

Thanks a lot!
 

Attachments

  • DSC00176.jpg
    DSC00176.jpg
    474.9 KB · Views: 433
  • DSC00177.jpg
    DSC00177.jpg
    518.9 KB · Views: 419
yes, 0,8-0,9 mm should be better ! What's wrong with cardoard? It flexes and it isn't soundproof; it means that it vibrates together with the loudspeaker, thus producing extra-sound that originally isn't there ( in the record ). And that let it pass some sound, so a box isn't worth it if it doesn't "stop" the rear radiation.
I would suggest to make two distinct boxes and with the speakers mounted frontally, not from the rear, if it's possible. Of course the reflex duct wouldn't be shared !
 
Did you compensate for the driver displacement and port volume? That port and two 2-inch drivers would already displace almost 100cc, which is almost 10% of the volume. I suspect that the internal volume is too small, and the port too long.

As for having separate chambers, if they were to run in mono the two drivers would be fine sharing that same volume. But, if you run them stereo the tuning would be off at times when the drivers operate individually, and the idle driver will be pushed about by the operating driver.
 
with a free air resonance of 134 hz i don't care what box or material is used there not gonna make bass for love nor money...
i'd add a six inch sub driver(mono) and use the F85's above 150hz

you would be nearer the size of a lunch box
 
Last edited:
frugal-phile™
Joined 2001
Paid Member
1st, MDF is not a greta material for building speakers. Particularily if you want to have thin walls. Use quality plywood.

The box should be divided into 2 parts. With 9mm ply, i estimate the driver to take up 30ml. This assumes that the back of the cutout is relieved (round-over or 45° chamfer).

Sealed a ½ litre gives pretty close to butterworth = 0.707 roll-off, maximally flat. You could get away with tuning it to 100 Hz, the vent would need to be external and i would prefer a slot. If you make it 6mm tall and 50 mm wide it would need to be 178mm long. It could probably start at the back of the box near the middle and wrap around the side to exit out the front. It is small enuff that it might chuff a bit, but the extra R in the vent will help and that same R will tend to flatten the bump in response. F10 in the low 70s.

attachment.php


dave
 

Attachments

  • Fountek-FR58ex-sim.png
    Fountek-FR58ex-sim.png
    13.7 KB · Views: 587
frugal-phile™
Joined 2001
Paid Member
You could get away with tuning it to 100 Hz, the vent would need to be external and i would prefer a slot. If you make it 6mm tall and 50 mm wide it would need to be 178mm long. It could probably start at the back of the box near the middle and wrap around the side to exit out the front.

I thot this was an interesting box so i drew it up. Vent grew a bit, so not near as much issue with chuffing.

attachment.php


dave
 

Attachments

  • Fountek0FR58ex-doubleBox-111117.pdf
    22.5 KB · Views: 755
I thot this was an interesting box so i drew it up. Vent grew a bit, so not near as much issue with chuffing.

645210d1510436073-cabinet-sound-fountek0fr58ex-doublebox-111117-pdf


dave

Thank you so much!
Also really sorry for no reply, I forgot to check the 2nd page!

I haven't thought of a slot reflex and it really seems to be the best for what I'm doing! I will use a quality baltic birch 9mm plywood and separate the chambers. Will I need any baffle step correction/ any other electronin circuit or component between the amp and the drivers?

Also would it be possible (without compromising the sound) to make the whole speaker enlosure a bit longer (from 201mm to 270ish-mm)? This would off course mean shortening the depth of 145mm to retain the internal volume. Would it affect the vent and sound?


(As It's intended to be portable) do I have to add the amp and battery to the back of the whole speaker so it wouldn't be inside, or just as long I calculate for the volume of those parts, increase the internal volume and stuff it in the box there won't be a sound difference?

Thanks a ton!!
 
Dave,

Also thinking if making the vents down-firing would be a bad/good idea - assuming the spekers will be used on a solid, flat surface. I have 1/2" tall casing feet that can be used to lift up the bottom of the cabinet. That way the existing design can be turned on its side and the drivers mounted on the new facing side. I wonder if the the shallower cabinet (62mm vs 112mm earlier) would hamper in any way? Coupling of the ports with the table top /shelf top might create issues or actually augment the low end?
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.