Woofer Configuration? Also, Series vs. Parallel?

[BigT]

I want to use a pair of 15" woofers for my 5-way quad-amped speaker project (main speakers are 4-way, with subwoofer makes it 5-way). I will be aligning all driver centers on a vertical line but if I mount both woofers this way, the speaker will be taller (~60" or 5") than I'd like with the tweeter positioned well above my head. I'd rather the tweeter be a bit lower. To allow for a less-tall enclosure, would there be a disadvantage to mounting one woofer on, say, the back of the enclosure? Or both on the sides? Anticipated crossover to the next driver will be ~300Hz. My current speakers, Legacy Focus, features three woofers, two mounted vertically in front and one in back. Vents are on the back also. I don't seem to notice a downside to this and since we're talking about long wavelengths, I'm guessing that in practice, the disadvantage is small.

Also, what is the advantages and disadvantges of series and parallel wiring? I understand about the increased impedance of series wiring and decreased impedance of parallel wiring, but what are the performance pluses and minuses of each method?

[servicetech]

I would select series or parallel based on your amp. What is the impedance of the woofers and what will your amp handle?

I don't see a problem putting the subwoofers on the sides of the enclosure to save height, a lot of commercial speakers do it.

[BigT]

There will be many amps - quad-amped, as I mentioned. My current amp is a Crown Macro Reference. Does very well on low impedances. But I may be using this for my subwoofer as it has a parallel-mono mode for very low impedances. So no worries there. Other amps have yet to be decided on, but for the woofer section I will be getting something suitable for the load.

[servicetech]

Most high quality amps will run 4 ohm loads w/o any problems.

[BigT]

Ok - thanks for the replies but enough about amps - I'd like an answer to my speaker questions. a.) Is there any downside to mounting one woofer on the front and one on the back? 2.) What are the advantages and disadvantages, speakerwise - not talking amps here - between series and parallel connections. This system will use an electronic crossover ahead of the amps so we don't need to worry about the problems that come with a passive crossover.

[servicetech]

There is no difference between series and parallel connections as far as sound quality is concerned.

A rear woofer could have some issues depending on how far you plan on putting it from the wall.

[Dennis H]

300 Hz is pushing it for a rear woofer. The wavelength is only about 4 feet so you're putting them a significant fraction of a wavelength apart. If the box were 2 feet deep, they'd be 180 degrees out of phase.

[NEO Dan]

you could put a 15" at the top and bottom, with the rest of the drivers in between.

[BigT]

300 Hz is pushing it for a rear woofer. The wavelength is only about 4 feet so you're putting them a significant fraction of a wavelength apart. If the box were 2 feet deep, they'd be 180 degrees out of phase.

Likely my box will be two feet deep, possibly more. How about one on the front and one on a side, as close to the front as is practical? Anyone ever try that? Might have to mount them side by side on the front and make a wide base but I don't know if that will work in my situation.

[BigT]

you could put a 15" at the top and bottom, with the rest of the drivers in between.

But then I lose the coupling advantage of using multiple woofers close together. I would also lose the coupling advantage by mounting one in front and one in back. Looking more and more that I will either use one woofer or two side by side.

[Dennis H]

But then I lose the coupling advantage of using multiple woofers close together

Not really. They will be within a wavelength of each other vertically and the woofer-ear distance of the two will be nearly identical assuming everything is centered around the tweeter at ear height. That's what I'd do, mount one high and one low. See the Statements and Khanspires threads for examples, albeit with smaller woofers.

https://www.htguide.com/forum/showthread.php?t=28728

https://www.htguide.com/forum/showthread.php?t=26309