10.8 square metres.
How bad could a £150 Wharfdale SW150 be?
For the money there's not a lot to compete with the SW150. I'll say that again... For. The. Money.
What are your alternatives right now at a similar kind of price? The £149 Tibo Harmony; an 8" reflex sub with a 100W amp and no real pedigree in this sector....... Pass. The Polk PSW10e at £179? A 50W reflex sub but this time with a 10" driver. It's better made than the Tibo, but do you really want to throw and extra £30 at this compared to the Wharfedale for just a 50W amp? Hmm... How about the £199 Q Acoustics 3070S with its slim design and twin 6.5" drivers. That's great if SWMBO says the choice is "
it lives in the skinny space behind the sofa or you get no sub at all", but that's really it's niche. It's a "
lifestyle" sub for the whipped.
Below £150??? Well, unless you're buying an
open box (return) product or some clearance deal then there really isn't much out there.
The conclusion then is that the Wharfedale is the smarter choice at just £150. It comes from a company that has been building loudspeakers for almost 90 years, and one that has won many awards and plaudits. The 150 sub combines a 10" driver with a 150W class D amp plate with both low- and high-level* drive options (*unusual at the price) with the economies of scale that come from volume production in China. The ported (reflex) design gives a useful boost to audible output which makes the sub loud enough to keep movie enthusiasts happy for the price.
So, the 150 is a slam-dunk, right?
Not exactly. On paper it looks great, and in the flesh you'd be hard pressed to be really critical of the build. Where things start to get a little loose at the seams is with the performance. More than a few users have commented that it never really digs as deep at the specs suggest, and finding a place in the room where it's happy can be... er... challenging. IMO these are both issues relating to entry-level ported designs.
The port is useful for getting more output per Watt of amp power compared to sealed designs, but like all things, there are some compromises. The port works a bit like
blowing over the top of an empty bottle. It's not letting more bass out. Instead you're hearing a tuned note; the port resonance. This means that once the speaker gets down to a certain frequency then you're hearing the port rather than the driver. In effect, the bass extension hits a sonic brick wall below which the sub doesn't do anything useful. Contrast this with sealed box sub designs (no reflex port). They don't go as loud Watt for Watt, but neither do they suffer the brick wall cut-off effect. Sealed subs go deeper for that
bass-you-can-feel effect so long as there's enough power on tap.
Being sealed also makes these subs easier to place in room. This is to do with something called room gain.
At first reading, the idea that you get a bass boost simply by virtue of putting a sub in a room sounds like a win-win. Free extra bass. What's not to love, right? Except it's not quite that straightforward.
You see, ported subs (and ported loudspeakers for that matter) have a fairly linear output as the frequency falls. If you were to measure a ported- versus a sealed-box sub out in an open field, the sealed box would show a bass roll off as the frequency drops whereas the ported box wouldn't until the measurement point gets lower than the port frequency.
Take the sealed sub and put it in a room though and suddenly the room's effect flattens the response curve. Now the sealed sub looks far more linear; a flat line, and that's good. The room gain compensates for the sealed sub's roll off. It's a bit counterintuitive, but as long as there's enough power from the internal amp, then the smaller sealed sub delivers cleaner and more extended bass than the larger-boxed ported sub. (
What?!!!). The catch is amp power, and also driver quality, but mostly amp power.
When you put the ported sub in a room then the same room gain effect occurs. This time though the resulting frequency response is anything but flat. There's a steadily rising hump as frequency falls. The result is boomy bass that you can never really flatten out regardless of room position. It gets worse in the room corners, but never goes away even when the sub is positioned further along a wall. The smaller the room then the higher the frequency that room gain starts to kick in. Where the driver itself is maybe not so linear due to cost compromises, and maybe too the cabinet construction is a bit resonant, then this can contribute to a lack of precision on top of the effects of room gain.
SVS has a good primer on room gain complete with some simple graphs. It's worth a read:
https://www.svsound.com/blogs/subwoofer-setup-and-tuning/what-is-subwoofer-room-gain
Your start point was a REL 1003, a sealed 10" 300W sub which sells for around the £400 mark. Now you're looking at a £150 ported 10" 150W Wharfedale. It's a country mile away in terms of performance compared to the REL, not to mention being physically larger and potentially more difficult to place due to the room size. If you had a budget movie/gaming system and £200 was your absolute limit then I could make a convincing case for the SW150. On its own merits it's a good sub for movies and gaming. Less so for music, but there isn't anything head-and-shoulders better under £200 unless there's something on a one-off clearance deal.
At £250 I think a Gemini II versus the Wharfedale - especially if music is important - would walk it in a room like yours. As
@hornetstinger suggested, and XLS200 would beat the Gemini II, but at that point the REL HT/1003 comes in cheaper for a similar spec.
LINKS
Reflex port resonance (Helmholtz frequency):
https://www.youtube.com/watch?v=PZVeJ2rh6ts
