Help with small Subwoofer project

[Allan74]

I am planning to build a PAIR of Subwoofer enclosures to act as end caps to my TV stand, with a single DIY 'SoundBar' laying across the top for center/L/R.

The goal:
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- Build 2 identical Subwoofer enclosures, each using 2 drivers each, each driver (in cabinet) 180deg away from each other (front/back firing out of phase?).

- Each cabinet presents a final nominal load of 8ohms/each (so, either a pair of 4 or 16ohm drivers each).

- Each cabinet is happy seeing 150W RMS @ 8ohms.

- Both cabinets to be powered using common BASH300, 300w plate amp. 1 cabinet 'always on' @ 150w RMS x 1 @ 8ohms, second cabinet 'switched-on' in parallel to achieve final 4 ohm load, amplifier will run 300w x 1 @ 4ohms. (2 stage 'apartment living' subwoofing....lol...or 'wife' useage)

- Use 4 x 8" drivers. each driver = 4 or 16hms/each, 75w RMS/each.

Can anyone recommend any 8" drivers that would suit this application ?

They don't have to be the 'BE-ALL/END-ALL' of 8" drivers, as this is just my primary setup that will be backed up, when needed (or able to) by a 1,000w-powered 15" driver.....

I am going to continue with my simple plan of......

[Allan74]

As of right now, these seem to be the front-runners......and also went on sale today for half price as it were:

Dayton SD215-88 8" Shielded DVC Subwoofer, Dual 8ohm DVC, 80w RMS, Shielded.

Dayton SD215-88 8" Shielded DVC Subwoofer | Parts-Express.com

Anyone offer anything to talk me out of using 4 of these ?

[Allan74]

Another thing I was considering, to keep things simple, rather than a ported enclosure, was to use a matching PASSIVE RADIATOR.....

Here's what it would look like from the top:

[Allan74]

I should also add....

These 8's will most likely be running up to 120-150hz on a gentle slope (12db/oct), to blend a little better with the top end which will consist of 3-4" drivers and tweeters only. I am willing to sacrifice bottom end (40hz) to better blend the top end, with this portion of the setup.

As I said previously, when needed, I will be 'turning on' the 1,000w 15"....but will stay dormant for the most part, as the wife is not a big-bass fan.

[Cal Weldon]

You will want to run them in phase and if you are planning a PR system, the PR's should be around 2X the cone area of the active drivers.

[Allan74]

Originally Posted by Cal Weldon

You will want to run them in phase and if you are planning a PR system, the PR's should be around 2X the cone area of the active drivers.

So, wiring the 2 active woofers IN PHASE with each other, then accomodating a 1:1 ratio of Active to Passive cone area, will this work ?

Or, would a side-firing port in place of the passive radiators be easier to deal with and tune ?



Alternatively...top/bottom staggered woofers ?

[Top Shelf]

I should think both 8"ers would work better coupled together on the
same side of the box, unless you're looking for some sort of time
smeared bass rig? I agree with Cal about the polarity too.

[Allan74]

Originally Posted by Top Shelf

I should think both 8"ers would work better coupled together on the
same side of the box, unless you're looking for some sort of time
smeared bass rig? I agree with Cal about the polarity too.

I was actually hoping to achieve the results I was looking for, by wiring the front/rear woofers out of phase......

Would completely ditching the PR's in favour of a side-firing port, and out of phase woofers be a more favorable solution ?

OR, does this entire plan just smell a little too much like a huge time alignment/phasing problem from the start ?

[Allan74]

Lastly.....The SIMPLE DESIGN ?



2 x 8" Subwoofers firing forward, 2 x 8" Passive Radiators in rear of SEALED cabinet.

Now, would the PR's make more of a possitive contribution being 180deg off the active drivers ? or 90deg off, with the passives firing out the side of the enclosure ?

[Top Shelf]

What are you hoping to acheieve with the woofers out of "phase"? You
could just skip the one woofer and go with an OB.