can I add additional Full range driver to my enclosure

[shuggi67]

I'm hoping I can get some help here.
currently I have a a set of wharfedale pacific p-40 floor standers that I use as part of 5.1 setup, However I am adding a low power valve amp, probably set 845 and wife will not let me have 2 sets of speakers for fronts. Nor will she probably allow me to buy new one's and ditch the currents ones.
So I got to thinking what if I could just make the bottom front port large enough to fit another speaker driver, create another port at the bottom for the reflex and just move all the current drivers down 1 slot.
Then add a full range driver to the top slot and connect the speaker cable directly to the new driver, and leave the others as they where i.e I would have speaker cable connected to the existing inefficient drivers that would be connected to the AV receiver, and separate cable connected directly to the full range driver for the set amp.

Can this be done ?? the specs of the speakers are below, The guy from Audio Nirvana said it should not be an issue but I wanted to see if anyone here had tried this.

Thanks in advance

Specifications
Wharfedale Pacific Pi-40 3-way bass-reflex tower speaker
Drivers: 1" cloth-dome tweeter, 6.5 Kevlar midrange cone, 6.5 Kevlar woofer cone
Input connectors: gold-plated 5-way binding posts, biwirable
Frequency response: 30Hz–20kHz, ±3dB
Sensitivity: 89dB/W/m
Crossovers: 60Hz, 3.5kHz
Recommended amplification: 40–200W
Dimensions: 43" x 9" x 14.5" D (HxWxD)
Weight: 53 lbs
Impedance: 6ohms

[rjbond3rd]

Hi shuggi,

Okay, so you have a floorstander with 2 6.5" drivers. You want to (a) relocate the port, (b) enlarge the old port to accept the lower 6.5" driver, and (c) move the upper 6.5" to where the lower one _was_, then use the newly empty hole for a full-range 6.5" driver.

You could do this, but it's a feat of engineering to do it properly. A lot of calculations go into making an enclosure, e.g. the volume, the center-to-center spacing of the drivers, the location of the port, the distance of port from the bottom etc.

If you do attempt this, you should be aware that the 2 6.5" drivers are almost certainly not putting out the same sound. The lower one is presumably rolled off at a certain frequency (to reinforce the bass but not the midrange).

One of the challenges you will face is whether you are going to put an internal divider between the full-ranger and the rest of the design. If you do, you've reduced the volume for the two 6.5" woofers (which will definitely affect performance -- but in your exact circumstances, maybe it can be done acceptably). Then you have to consider the volume of the fullranger's internal partition, and whether to add a port.

But it sounds like you're not considering a partition. In that case, the results will be a bit unpredictable as the two woofers will act as passive radiators. You really need to calculate a proper enclosure and this is hit or miss. But if you go this way, my advice would be to consider stuffing the port when the fullranger is playing, as there's really not much sense in having both a port and passive radiators (it's one or the other).

The AN guy says a lot of things but making a proper enclosure is a design process, and here, you're sort of hoping for the best. Hey, I've done crazier things but the results weren't usually all that stunning. But if you're feeling experimental, hey, it's one way to learn. But if those Wharfdales are worth a lot of money, I'd say don't do it.

[shuggi67]

Thanks for that, and you have convinced me not to do it now.
Damn, Damn, Damn, guess I'll just have to go with a higher powered amp.
Is there nothing that could be done to improve there current efficiency rating, and extra 3 dbm would be enough, I imagine it would be to replace all the drivers and crossover and a lot of hassle.

[rjbond3rd]

I think you should work with whatever you have. Maybe they won't play loud, but they may play sweetly with your amp. Finding the right fullrange setup is worth the hassle, and the searching. (Incidentally, some people, me included, ditched their 5.1 setups after getting a nice tube / stereo setup -- your wife might approve.

[shuggi67]

Things have just change.... The ball and chain has agreed I can purchase or DIY an additional set of front speakers long as they are not huge, i.e monitor style only, bass may suffer a little but I run a REL t1 Sub anyway so no real loss.
Can you recommend any good threads with monitor type enclosures that would sound great, was looking at open baffle but read that the sound is really only good for classical.

[rjbond3rd]

Hi shuggi, congratulations, that's an easier path to better results. Here's one place to start: http://www.geocities.com/rbrines1/Products.html

Open baffle is not limited to any genre, but takes some space. For that, you might start here: http://www.quarter-wave.com/Project08/Project08.html

[shuggi67]

Brilliant thanks for the advice