...and other questions...
I have a set of four Peerless XLS10 4 Ohm (830452) drivers. I've been running a pair in a 40 litre (1.4 cu ft) sealed enclosure. The drivers are mounted on opposing faces of the box, wired in series to create an 8 Ohm load, and have been run off an Alesis RA500 amp (in bridged mode - claimed to deliver 500w into 8 Ohm). I'm quite happy with the amp dialled to around 50% volume (it measures level with an SPL meter with respect to my other speakers).
I'd like to make use of the other two drivers, and create a pair of subs for better room response.
I'm very tempted to look into ported enclosures, accepting that the XLS10 does appear to need large ports.
A quick design in BassBox Pro indicates 40 litres sealed, or 52 litres (1.8 cu ft) ported. Reducing the ported design to 45 litres (1.6 cu ft) doesn't appear to make a huge difference to the response, but still gives a reasonable SPL boost over the sealed enclosure (see attached image).
My initial plan was to run the RA500 amp in stereo mode (claimed 150w per channel into 8 Ohm in this configuration). I know this is less power than desirable, but as I run the amp pretty low now I'm hoping this will be sufficient.
Working on the assumption of 150w, the 45l ported enclosure hits the drivers' excursion limit at 14.8Hz. A sealed 45l enclosure looks safe (excursion limit hit at 7Hz, but only runs 0.5mm over at 5Hz).
Vent air velocity looks acceptable, at a max of 17.4m/s at 22Hz.
With this design, it looks like room constraints are going to force me into having both drivers on one face of a 50x50x35cm enclosure (20x20x14").
So, the questions...
- Am I completely kidding myself that the one amp will suffice (150w to each pair of drivers)?
- Should I worry about having both drivers on one face (opposing faces seems to cancel out the vibrations quite well)? I guess the enclosures will be pretty heavy, so shouldn't move much.
- I'm thinking that I could initially stuff the ports to make the boxes sealed, until I get a high pass filter to prevent driver damage. Sensible idea? Pointless to try to make one box to do both? Give up on the ported altogether and go for sealed?
- Any point in stuffing/damping the internals of a sub, given it's strictly for <100Hz?
- I have two floorstanding main speakers. For movies it's obviously the subs doing the LFE work, for music I don't tend to use the subs that often, but sometimes send bass to the speakers and subs for a bit of extra depth. Should I care about phase, given the RA500 doesn't have any phase setting?
Any thoughts/advice greatly appreciated!
PS I know the correct answer is either "use an XYZ brand/model driver instead" or "make 4 small subs, each with one XLS10 and a passive radiator". I've got 4 XLS10s, and an awkward room, so I'd like to try to get a reasonable solution with what I have!
