Frequency Range/18"/Subwoofers

[fusionbassist1]

Yo yo yo. I'm going to stop going on about large speakers after this topic I promise!

I'm looking to buy a new 18" speaker to put in an old cabinet i've aquired and have come across some issues that i'd much appreciate having cleared up by members of this fantastic forum.

The first thing I came across is Frequency Response/Range in speakers. In 18" speakers there seems to be a huge range from one manufactured to another of the frequency range their speakers have. Fane's 18XB having a range from 27Hz to 1kHz and on the other hand Precision Devices' PDN.18SB40 has a huge range from 40Hz to 3.5kHz. My thought is that any frequency below 40Hz is pretty much useless due to me being a 4 string player and that a large range is good so that it's not just really low bass that's coming from the 18" cabinet. Can someone help on this??

While I'm here I'll ask about Neodymium speakers (due to the PDN.18SB40 being neodymium). Are there any flaws to having a large neodymium speaker? My initial thoughts were great as an 18" is big enough without having to break your back getting it off the floor but then it crossed my mind that large speakers need to be weighed down somehow due to the power and freq.s they pump out....

Another thing that baffled me in the search for speakers on bluearan was what exactly a subwoofer is. I've always associated subwoofers with pa systems etc but it never crossed my mind if a speaker labeled 'subwoofer' could be used in the same way a guitar/bass speaker can. I shouldn't really think there's a problem with using pa equipement anyway as i know there's some people on the forum who do just that for a hi-fi sounding rig. Is subwoofer just a fancy name for a speaker for low frequency application??

If anyone has absolutely any muses about 18" speakers to share pelase do as i'd much appreciate all the info I can get. I haven't had much response in other topics so i'm still a bit overwelmed. Anything at all...honestly....Thanx a lot everyone,

FB1

[Bill Fitzmaurice]

[quote name='fusionbassist1' post='80147' date='Oct 27 2007, 10:48 AM']If anyone has absolutely any muses about 18" speakers to share pelase do as i'd much appreciate all the info I can get. I haven't had much response in other topics so i'm still a bit overwelmed. Anything at all...honestly....Thanx a lot everyone,

FB1[/quote]My main advice with respect to an 18 is don't use one. Modern drivers don't have to be so large to deliver what you need, and as far as electric bass is concerned there's no need for an 18 whatsoever. Beyond that, response, sensitivity and usable output are determined by the combination of the cabinet and driver, and they must be precisely matched to work correctly. You can't separate the function of the one from the other, so if you're thinking about loading a new driver into an old box you'll have to use a speaker design program to find out what will work best in that box.