When it comes to audio i'm a complete newby, what he doesnt want is to need to have a stand alone subwoofer, that's why he liked the old sony's
he used to have.
So he doesn't want a sub, doesn't want towers, yet expects deep bass for 500 dollars or less?
(yikes)
First of all, the problem that arises that the best place for speaker imaging can often be a bad place for deep bass and cause nulls and peaks which don't sound all that great.
Second, in a large bookshelf / mini tower, you're enclosure volume limited. This makes it rather tough for even large drivers to output bass.
Third, Wide-baffle speakers with huge drivers have their own shortcomings and are so 70s anyways! They don't make em anymore because they're just not all that great. I've got some Sony towers from the 90s with 12" woofers and probably 16 inch baffle in my house. To say they image poorly would be an understatement.. "they don't image at all" is more like it. Switching to headphones or good speakers can at times be unsettling when coming from the sonys, never mind detail or clarity etc... the imaging is like night and day.
So with all that in mind, i'll still try to suggest a speaker. It's generally said that up to around 20hz is audible to most people. The average bookshelf can extend down to around 80hz, which usually means you've got around two octaves where a subwoofer is expected to function. Even many towers struggle to get down to around 40hz, which still leaves an octave(or 3 ...a
real man's system needs to go down to 5hz!!!!!!!!!! Think of the subsonics!) that you'd expect a sub to cover. I doubt your buddy's system goes much lower than 40hz either but i can't make a definitive statement.
So let's look at one of the speakers I posted earlier that roughly fits into what your friend wants... the Ascend CMT-340
This is an LCR speaker. They're often used as center channels paired with towers and bookshelves, but can very much be used in stereo mode. A vertical MTM can sound very nice in stereo. It's not a tower, but at 21" tall it's most certainly not a "tiny" bookshelf. With two 6.5" woofers instead of one 5" woofer like a lot of bookshelves, it's certainly capable of more output and deeper extension. The only caveat is that the tweeter must be at ear level, as the woofers above and below it have an effect on vertical dispersion.
SO let's look at the specs:
-Listed at 568 + 30 dollars shipping / pair - it goes over budget a bit that's a given with anything I post.
-It's got a sensitivity of 90dB, which is definitely a good thing for a small speaker as they often tend to be unsensitive compared to towers. It's also 8 ohms, so it should be an easy to drive load for pretty much any receiver.
-It's got an anechoic FR listed at 48Hz - 24kHz +/- 3dB - this is rather deep and will definitely give sufficient bass...you'll still be missing stuff from around 20-45hz in-room but I'd be willing to bet your friend's sony with the 10" woofers probably don't get all that low either.
-It can handle 240 watts of power. While it'll probably run into distortion earlier than that, it's still rather safe to say he can run these things to reference levels.
So he could probably get away with that speaker being used full range. It won't give him full range, but it would come close. I'd still be careful of woofer bottoming below tuning though.
On the other hand, using a sub would be just wicked. It could give him the entire audible range, take a load off the amplifier, and also give him the best in-room integration of bass.
