Basic Speakerbuilding questions

[NoTalent]

Hello all, I have been reading these forums for a few weeks now and I decided to try and build my first speaker project: a powered subwoofer.

I chose the Adire Tempest, with a 250W plate amp (PE#: 300-794 ).

I just have a few questions on the actual construction of the box:

1) Mounting the speaker: Do I need anything to seal the driver itself into the box? I have some sealing caulk that I purchased. Will this be OK?

2) Polyfill: I have some acousta-stuff polyfill. Since the tempest is going to be mounted in a down-firing orientation, is it safe to just put the polyfill in the sealed box? Or should I attach it to the walls so it doesn't come in contact with the driver?

3) Polyfill Is there a cheaper alternative? Can I use the stuff inside cheap pillows, or maybe the pink fiberglass insulation?

I hope this project goes well (unlike Not happy with my DIY Tempest) and I'll post pictures

Regards,
NoTalent

[roddyama]

1.) Yes it is necessary to seal the driver in the baffle. Sealing Caulk is ok used sparingly. It is also preferable if is not petroleum based.

2.) You do not want the filling to contact the driver. You may want to get some chicken wire and make a frame that cleares the driver by about 2" or so. Than get some "chesse cloth" type material from a fabric store to cover the chicken wire frame. That will keep the loose fibers out of the driver.

3.) Fiberglass insulation is easy to get at Home Depot type stores and is more efficient that Polyester Fiber (pillow fill). The problem is that fiberglass is a PIA. Gloves and a mask are a must. I would also worry about the loose fiber getting in the downward facing woofer. Rock Wool, if you can find it is about the best you can use. It is 20 to 25% more efficient than fiberglass which is about 20 to 25% more efficient than pillow fill (depending on your installation.) Remember that the fill will make the box "look" bigger to the driver. Don't forget to consider this when you calculate the box size.

[Da5id4Vz]

The problem is that fiberglass is a PIA.

Ive had fiberglass effect me in a lot of places, but if this is true, well I dont think any of us want to know how you are handling it.

[roddyama]

Originally posted by Da5id4Vz


Ive had fiberglass effect me in a lot of places, but if this is true, well I dont think any of us want to know how you are handling it.

Let me put it this way, if you've upset your wife, hide the fiberglass insulation at laundry time. (Just kidding of course )

[Da5id4Vz]

oh my!

[NoTalent]

Thankyou for the quick answer.

What should I use to connect the power amp to the speaker with (inside the sealed box)? I have some 16g speaker wire--will this do? Also, what should I connect the wire to the speaker with? I was thinking of using a 'solderless disconnect' (PE# 095-270). Or should I just solder the speaker wire to the speaker and the amp?

Regards,
NoTalent

[roddyama]

Take a look at this article by Nelson Pass on speaker cables. Than decide what you would like to do.

[NoTalent]

Thanks for that link Rodd.

One other question I have about speaker building.

I know MDF is 'Medium' Density Fiberboard. Is there a HDF (heavy) or LDF (Light)? If so, is the heavier better to build speakerboxes with? I have never seen it if it exists.

[roddyama]

Originally posted by NoTalent
Thanks for that link Rodd.

One other question I have about speaker building.

I know MDF is 'Medium' Density Fiberboard. Is there a HDF (heavy) or LDF (Light)? If so, is the heavier better to build speakerboxes with? I have never seen it if it exists.

I used an early version of HDF to build my subs 20 years ago. I had to order it special at a lumber yard. I would think that the heavy or light varieties are still hard to find off the shelf, while you can get MDF at Home Depot all day long. No good reason not to use MDF or marine plywood (void free).

[Timn8ter]

Follow the plans on Adire's website. There are pics on my site under the Adire Audio heading. Use polyester batting if you can and just layer it up to the appropriate thickness on the walls and bracing. You can use 3M Spray Adhesive.