DIY speakers

HoopsOnToast

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hi,

during my new speaker quest, i am thining of going diy again.

does anyone know much about crossovers or baffle step correction?

i know a little, and about the different types of crossovers but not know which one is suitable for my design.

after a lot of ideas and advice on diy sites, i have come up with this...

the design is a Fostex FX120 (89dB) or FE108EZ (90dB) full range in open baffle crossed to a Volt B250.8 (89dB) woofer in a closed box @300Hz.

a pic....

picik8.png


any opinions?

 
E

earl of sodbury

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Never heard anything remotely like it, but it certainly looks interesting.

Could you reduce the upper baffle to a minimum to reduce baffle diffraction from the mid/upper driver, or does being open baffle require the baffle be very wide?

No idea about x-overs - do full-range drivers need much more than a couple of resistors?

Hopefully someone who knows what they're talking about will be along in a minute... :minikiev:

 

HoopsOnToast

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well, from what i understand, a wider baffle reduces the need for baffle step correction i think, and the bass enclosure was moddeled in winisd, so that should be ok, acording to some simulators, i first order crossover (6dB per octave) at 300Hz is the simplest, with just two components per side (an inductor and capacitor), but i have never made one before so i dunno lol!

 
E

earl of sodbury

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TannoyBoy wrote:

well, from what i understand, a wider baffle reduces the need for baffle step correction i think, and the bass enclosure was moddeled in winisd, so that should be ok, acording to some simulators, i first order crossover (6dB per octave) at 300Hz is the simplest, with just two components per side (an inductor and capacitor), but i have never made one before so i dunno lol!
OK, I read you.

With such a simple "cross-over" you can just buy some cheapcaps from Maplins and experiment with different values, and hand-wind the inductors to roughly the value you think you want then wind on/off a quarter turn at a time until they sound right.

 
E

earl of sodbury

Guest
TannoyBoy wrote:

well, from what i understand, a wider baffle reduces the need for baffle step correction i think, and the bass enclosure was moddeled in winisd, so that should be ok, acording to some simulators, i first order crossover (6dB per octave) at 300Hz is the simplest, with just two components per side (an inductor and capacitor), but i have never made one before so i dunno lol!
OK, I read you.

With such a simple "cross-over" you can just buy some cheapcaps from Maplins and experiment with different values, and hand-wind the inductors to roughly the value you think you want then wind on/off a quarter turn at a time until they sound right...

churz, eofs

 
M

murray johnson

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A couple of points. Some, possibly many, speaker companies wouldn't put a crossover at 300 Hz. Its a bit of a critical area where voices and the bulk of many instruments reside. You might want to do it a bit lower.

The 6 dB per octave filtering doesn't take into account the drivers own characteristics & roll off and general 'out of band' behaviour. Its not as if either would just carry on flat forever upwards or downwards if no filtering was applied.

Having said that a Volt driver used in an IB configuration should give a good bass performance if the box is sturdy enough. It'll just be interesting to see whether its character when loaded like that can be made to match that of an open baffle Fostex.

What do Wilmslow say about this?

 

HoopsOnToast

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thanks, i have emailed wilmslow audio yesterday, no reply yet.

i dont really know much about crossovers, so any advice is welcome.

i chose the fostex for the superior mid and the no need for a tweeter, and the volt for the quality, boom-less bass in a relatively small box.

 

HoopsOnToast

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hi, yeah i did think about it, but chose to go with a full range and bass help to stop the full range being stressed at higher volumes which can only be a good thing for the midrange.

 

odell

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They actually sell Fostex and Lowther drivers from their parent site:

http://www.commonsenseaudio.com/

Fostex must be a lot more tolerant of their dealers than some companies!

Like so much in Hi-Fi it's difficult to know how seriously to take all the claims being made on the site, although it's definately not a slick marketing operation!

On balance these look like these may well be worth a try for a DIY beginner like me - no cross over to balls up, simple cabinet and not very expensive to start with.

 

HoopsOnToast

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hi, a good shop to get full range drivers from is http://www.spectrumaudio.de/ even though its german, the prices are good and i theink delivery is reasonable.

if you want Open Baffle, the visaton b200 is supposed to be the best, and obviously the fostex, or audio nivana are best in horn loaded speakers, the css fr125s (which i have used before) is very good, although wont go party loud.

if you want to experiment, cheaper drivers like the pioneer b20, beyma 8AG/N, ciare ch250, monacor and tangbands all deliver cheap frills that are supprisingly good for the price.

i post on diyaudio.com and fullrangedriver.com, both will offer great advice.

 

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