New to Full Range speakers...questions though

[karlton]

I know my questions have probably been answered many times,but....I am on a VERY slow dial-up system ....and have limited electricity so I need to be specific to narrow down the info. I apologize in advance.

To keep it simple...I want to build a simple set of full range speakers. They will be for a 12' x 12' room with 8' ceiling.

I like all kinds of music,jazz and blues are my favorite.

I am a carpenter/woodworker,so the cabinets are my forte.

My main question is...what drivers would you pick? I live in the USA,so thinking Fostex is the choice? I pretty much know nothing on the speaker part. I have read many threads but they confuse the heck out of me.

So i guess these are my questions.

#1 What driver?

#2 What size cabinet

#3 Do full range drivers need special wireing(caps,resistors,etc)...or just a simple direct connect ?

Sorry for the dumb questions,but i have to start somewhere.

Thanks.

[planet10]

Originally Posted by karlton

#1 What driver?

#2 What size cabinet

#3 Do full range drivers need special wireing(caps,resistors,etc)...or just a simple direct connect ?

You don't want to much driver... you have a small room. Efficiency would be a boon if you need to conserve power.

FE127, FE126e, FE167, FE166 would be a short list of Fostex. eN versions for a step up.

Once you choose a driver pick an enclosure (althou the available enclosures available may hekp you choose the driver)

Personally i try to avoid filters, but sometime people find BSC or other FR teaking networks useful.

dave

[karlton]

Thanks for the info Dave.

When you say filters...what is that? BSC or FR ? Like I said I know VERY little abut full range speakers.

Maybe filter is a cap or resistor ?

I can build any enclosure to suit my room,just wondering what driver and what size enclosure to go with. Also what style enclosure.

thanks

[planet10]

BSC = Baffle Step Compensation

Baffle Diffraction Step

FR = Frequency Response

A few examples of filters are to notch out peaks (they reduce the peak's visibility in a FR chart, but the resonance that causes the peak is still there, so sometimes the cure is worse than the problem, my approach is to try to reduce/kill these at the sotce by modifying the driver), broadly reduce the midrange so that it is closer in level to a falling top & bottom (using a high output impedance amplifier can have much the same effect), or flatten out a rising top end.

dave

[Henkjan]

there are other nice full rangers as well, don't limit yourself to Fostex... CSS, Markaudio, Tangband, ....

1 question that is important to make a choice is if you will have a fixed listening position or not? if you have, then a large driver will be OK, if not you'll might want to go for a smaller driver.

[rjbond3rd]

Hi Karlton,

Lots of cool designs here: The Frugal-Horns Site -- High Performance, Low Cost DIY Horn Designs

Sounds like you have cornes as a possibility: Bigger Is Better 'BIB' Cabinet Dimensions - ZillaSpeak (click on "How to Build a BiB" and on the brands of drivers to see specifics).

If you crave an understanding of the principles, read these: Quarter Wavelength Loudspeaker Projects

Edit: dang, why does it convert URL's into page titles?

[karlton]

Thanks for the links and info. Looks like I have alot of reading to do. I really want to do this,but want a full understanding before I even start.

[Jim Shearer]

Originally Posted by karlton

Thanks for the links and info. Looks like I have alot of reading to do. I really want to do this,but want a full understanding before I even start.

Egad! A full understanding! If that's the case then your situation is dire! I agree that a good understanding is helpful, but I find that I can only learn some things by taking the plunge and actually doing.

And if you can't go listen to any of the drivers before you build, then all you can do is read plenty and take your best guess.

For your size room, I can say that I would be looking at something like a Fonken or a Metronome with a Fostex FE127e. You can find threads here about those designs.

BTW, no driver is perfect; no design is perfect. It all comes down to what compromises are acceptable to you--and only your ears can tell you that.

Good luck, Jim

[just a guy]

Originally Posted by planet10

Baffle Diffraction Step


dave

Just a quick note - and I'm sure you already know this - but baffle step and baffle diffraction are 2 very very different things. I did a quick skim of the link and it appears to describe baffle step. Unless I missed it, that link has nothing to do with diffraction.

[planet10]

Originally Posted by just a guy

Just a quick note - and I'm sure you already know this - but baffle step and baffle diffraction are 2 very very different things.

Actually they are manifestions of the same phenomena, that express themselves in different ways depending on the frequency in question and the radius of the cabinet edge. At the extremes they express in distict ways, but in the middle you get a mix of both, with a continuous transition from one expresion to the other as the frequency is ramped up or down.

If you look at the curves of the baffle step phenomena, the ripples seen in less ideal enclosures is baffle diffraction.

dave