Hi - for a 3 way speaker, is it always advisable to seperate the mid from effect of bass driver? Such as using a 'can' on the back or just boxing in as part of overall enclosure?
Thanks.
Thanks.
Yes give the mid its own chamber, unless it has a sealed back.
Boxing it in is the preferred method. Using a plastic can is quicker for manufacturing.
Boxing it in is the preferred method. Using a plastic can is quicker for manufacturing.
Yes, it's always advisable.
If the drivers share the same volume, the mid will act as a weirdly-tuned passive radiator, and will be getting pushed around by the bass driver.
Have a look at the Klippel curves to see why that's a bad idea.
Chris
If the drivers share the same volume, the mid will act as a weirdly-tuned passive radiator, and will be getting pushed around by the bass driver.
Have a look at the Klippel curves to see why that's a bad idea.
Chris
Unless you are doing oppen baffle you should isolate the midrange from the woofer , the woofer movement will afect pressure inside the cabin, the midrange hardly moves so it shouldnt be disturbed
Ok, great - thought as much - thanks for the replies.
What can be suggested for a Monacor SPH-102KEP 4-1/2" Kevlar Cone Midrange Driver?
I guess for a 3-way system I could opt for the mid to be at the top of the cab and section that off from the main enclosure used for bass, given typically 1" tweeter is effectively sealed?
Or... a plastic / metal can (maybe as designed for ceiling mounts) with external damping (such as bitumen pad type noise killer)
What can be suggested for a Monacor SPH-102KEP 4-1/2" Kevlar Cone Midrange Driver?
I guess for a 3-way system I could opt for the mid to be at the top of the cab and section that off from the main enclosure used for bass, given typically 1" tweeter is effectively sealed?
Or... a plastic / metal can (maybe as designed for ceiling mounts) with external damping (such as bitumen pad type noise killer)
If it’s a regular ‘box’ speaker any ‘can’ will do. No need for bitumen damping. And anything up from 1 liter will suffice. There are off the shelf options (look for pro suppliers) or diy options (tubing or household plastics). Or build a wood enclosure.
@markbakk - if I consider Monacor 4 1/2 inch driver and 125mm pipe (sorry to mix units), then around 200mm length will provide an unoccupied volume of 2.45 litres.
Should I be considering the volume behind the cone/driver for the 1 litre minimum or the whole enclosure?
Should I be considering the volume behind the cone/driver for the 1 litre minimum or the whole enclosure?
Don't make it too small, that can lead to a hump in the midbass. This can be seen if you sim the driver in a small closed box. I usually go for 2-4 litres, when I'm lazy, a piece of felt tacked over the driver works too....
a cone driver radiates mainly to its sides for the back wave, a dome driver radiates mainly straight backwards, i guess this should be considered when choosing the can shape
rear of mid speaker decisions
\you may note I yhave been posting recently on this same subject re Mission m71i and Wilmslow Audio allegro.
Some thoughts for easy implementantion are< that you can try using foam and sculpture out internal space at your leisure, as well as using pva to stiffen the outside areas . i intend to adopt this method , along with using a tuned port? My research shows that this port should be a minimim of near half the speaker size. Havent gotten that far yet. I personally have spent quite a few years messing around with this subject and can assure you that some of the bad advice re smaller size will have a bad effect on performance.It will work but depends upon what is acceptable. Too many paramaters involved from speaker design material stiffness volume levels etc etc etc . Too many specialist with their own favourite paramaters?
Mine will port intternally to the main inside box volume which will only have frequencies below 110 hz, and 2nd order above that. ie Not much too worry about with some longwool fibre absorbtion. Big picture means only a slight problem and nthen only when loud enough ? 😕
\you may note I yhave been posting recently on this same subject re Mission m71i and Wilmslow Audio allegro.
Some thoughts for easy implementantion are< that you can try using foam and sculpture out internal space at your leisure, as well as using pva to stiffen the outside areas . i intend to adopt this method , along with using a tuned port? My research shows that this port should be a minimim of near half the speaker size. Havent gotten that far yet. I personally have spent quite a few years messing around with this subject and can assure you that some of the bad advice re smaller size will have a bad effect on performance.It will work but depends upon what is acceptable. Too many paramaters involved from speaker design material stiffness volume levels etc etc etc . Too many specialist with their own favourite paramaters?
Mine will port intternally to the main inside box volume which will only have frequencies below 110 hz, and 2nd order above that. ie Not much too worry about with some longwool fibre absorbtion. Big picture means only a slight problem and nthen only when loud enough ? 😕
2.45 l will be ok. Stuff it well with a good damping material, like acoustic foam or mineral wool. What crossover do you intend to use?
PeteMcK and I often use empty tin cans as midrange "boxes", an A-10 is around 3.6 litres.
I often wrap them with duct tape and I fill with fibre as a matter of course, if I have scraps of carpet or felt around I line the tin with that first
I often wrap them with duct tape and I fill with fibre as a matter of course, if I have scraps of carpet or felt around I line the tin with that first
What exactly is that bad effect? Air being too springy? Absence of standing waves? Absence of panel resonances?
Well if the box "Q" goes above 1 and the driver is working anywhere near its pistonic range then yes I can see that it would have an effect. I like to cross to the mid as low as I can so my tendency is to use large enclosures and aim for a closed box "Q" of 0.7 to 0.5. All approximately
Don’t mix up resistive and resonant with pistonic. And what happens with a Q>1 when you apply a highpass function at about double or triple the resonant frequency? Again, the Q of a mid driver can only be determined when the band pass function of the crossover is applied. The Q of the unfiltered driver normally plays an unimportant side show. But one has to design the correct crossover of course.
What about if like myself you use low order crossovers?
A mid driver with an Fs of around 60 and crossed around 250/300 is still partially in its pistonic range if crossed second order and definitely so if only using one element prior or use Chebychev style
A mid driver with an Fs of around 60 and crossed around 250/300 is still partially in its pistonic range if crossed second order and definitely so if only using one element prior or use Chebychev style
If you wanna go the extra mile, here's a sound idea: What do you put in a sealed midrange enclosure?
You could even fill it with Twaron angel hair, if you can live with the idea of bald angels flying through the midst of heaven.
You could even fill it with Twaron angel hair, if you can live with the idea of bald angels flying through the midst of heaven.
I'm looking at a -12dB crossover, not certain about the frequencies. Bass driver Monacor SPH250-KE and probably as SEAS 1" tweeter.
Do you have thoughts on crossover frequencies for a ported enclosure?
I have thoughts and a definite opinion
Simply put I'd personally never use a ported enclosure for a midrange, sealed or OB but never ported, it's only a personal preference tho based on experience. Too much hard design work for my limited ability
Simply put I'd personally never use a ported enclosure for a midrange, sealed or OB but never ported, it's only a personal preference tho based on experience. Too much hard design work for my limited ability
The comment on ported enclosure referred to the overall construction of the loudspeaker, ie the bass driver is ported.
The mid would be in a sealed PVC enclosure cunningly manufactured using 5" or 6"thick-walled pipe with end cap and acoustically dampened.
The mid would be in a sealed PVC enclosure cunningly manufactured using 5" or 6"thick-walled pipe with end cap and acoustically dampened.