Slot Ported HDS315 Box Build

[ShadeTreeMechanic]

Here are some pictures of my box build. ( Moderators, if this belongs in a build section please move)

Soundcubed HDS315 next to a $10 woofer.

This thing looks like its going to be loud!

I found a box calculator on dbdynamixaudio.com They give a cut sheet and diagrams too.

It confirmed what Soundcubed recommended but the Soundcubed website was a little fuzzy on the port tuning.

The goal was to replace the 4 Pyle 15s with 2 15s that would be louder. I have had these Pyles about a year and they are the first DVC subs i have had. In the early 90s I had a pair of kicker 15s 8 ohm parallel on a Punch 200 bridged.

With the measurements of the truck of the truck and the Soundcubed recommendation that port volume will be about 18%, i figured out how to make a 9^ft box fit. This monster would take about a sheet and a half of plywood. This along with the drivers would make the box very heavy. Because i would periodically have to remove the box to haul stuff, i decided on two seperate boxes.

Time to cut some wood.

I used 3/4 plywood that has one good side on it. (I forget what its called)

[ShadeTreeMechanic]

The slot port is tuned to about 34hz. Slot ports along a wall will play lower than they are tuned because the wall acts as a port extension. One half port width distance along the wall belongs to the port.

Its starting to come together.

I used drywall screws and drilled and countersunk the holes. I also used Titebond III and caulked the joints with Liquid Nails construction adhesive.

[ShadeTreeMechanic]

Sides tied together with braces. I was careful to stay away from the port opening. Port opening braced too.

I bought a cheap mattress pad for damping material and wanted the egg crate foam style but all they had was this. This will keep the box for sounding hollow.

If it were a sealed box i would use poly fill.

Again i was careful to stay away from the port opening.

[ShadeTreeMechanic]

I ordered carpet from Parts Express but the boxes were done before it arrived. With the woofers sitting there and the boxes sitting there i just had to hear it.

I got the carpet but it will have to wait until the weather warms up.

I am running it on an Opti 4001D

This is the most bass i have ever had. It smashes the lows like crazy. The subs are rated at 1200 WRMS each. They are 2 ohm coils all in parallel for .5 ohms.

[mcfalcon]

Did you achieve your goal of being louder than the 4?

[ShadeTreeMechanic]

Did you achieve your goal of being louder than the 4?

Yes, this is the first time using a slot port and it is crazy loud. The port gives about a 5db gain and gets louder with less power. I had to turn the gain down a little to help keep balance with the highs. Even though both setups are .5 ohm, the 4 15s were power hungry and it was easier to hit the limits of the charging system with a 250A alternator and a single AGM starting battery.

[mcfalcon]

Nice. I have never had a proper slot port box and am very interested in doing one.

[ShadeTreeMechanic]

Nice. I have never had a proper slot port box and am very interested in doing one.

The added output from the port is amazing compared to a sealed enclosure. The only down side is the added output from the port is really loud only at the tuned frequency, which makes all the other bass above and below it comparatively quieter. But it sure is loud. I tuned mine to smash the lows and now my upper bass is lacking. My plans for biamped bass with 4 10s will cover the upper bass to even it out.

[MrSkippyJ]

hmm. sounds like something is off then. In my truck the roll off is pretty quick below tuning (as expected with ported enclosures) but the response above tuning doesn't lack at all. It might be worth experimenting with your box before trying to add speakers to cover the frequencies. Building boxes is much easier than trying to tune systems, especially when you start adding as many variables as you want too!

Just a thought though

[ShadeTreeMechanic]

hmm. sounds like something is off then. In my truck the roll off is pretty quick below tuning (as expected with ported enclosures) but the response above tuning doesn't lack at all. It might be worth experimenting with your box before trying to add speakers to cover the frequencies. Building boxes is much easier than trying to tune systems, especially when you start adding as many variables as you want too!

Just a thought though

Well its not that the upper bass is missing. Its just not as loud as the port. I thought about reducing the length of the port but then it wont smash the lows the same. I have a version of the song "Bass - I Love You" that has been slowed slightly. The subsonic filter on the amp is all the way down and the infrasonic notes it hits is crazy (bass you can feel but not hear). I would hate to loose that after waiting so long to find it. Thanks for your input.