Mid-woofer as midrange ?

[foo]

What's the benefit to use a mid-woofer as a midrange ?
Why do a lot of comercial designs use such allignment?

[wintermute]

IMO the main reason is because most "midranges" don't go low enough to match up with 10" or bigger woofers.

My 10" vifa woofers should be run at less than 500 Hz (I'm going to be running them to only 300 max with my current work in progress. Try finding a dedicated midrange that will be happy down to 300Hz, I think you will be pushing it to find much that is happy below about 600-800Hz

the other factor is that the critical freq for human voice (often debated) is between about 300Hz and 3,000 Hz so, a good midbass can handle this without the need for any crossover point in this critical range. (3000 might be pushing it a bit for a 5")....

Tony.

[foo]

BUT i think most midrange can also meet the area of 300hz~3000hz .
such as ss, vifa,etc .
there are so many mids can meet the spplication.
Especially Vifa P13MH is a cheap and good one.

[wintermute]

I suppose it depends on your definition of midrange a lot of so called midranges would be otherwise called midbass It's a bit of a fuzzy area. As an example I would say the vifa P13 was more of a midbass than a midrange.

IMO a true midrange should be capable of working up to about 5000Hz comfortably, you just can't do that with a 5" driver cause it will start beaming well before that (around 2,500Hz from memory.....)

It's all about compromises.... a dome mid like the morel MDM55 will have great detail but lack in the low end..... a midbass will be good in the low end but probably won't have the definition of a dome..... short of going for a four way design you have to compromise one way or the other.... (or you could use a fullrange )

Tony.

[bhg41088]

Originally posted by wintermute
IMO the main reason is because most "midranges" don't go low enough to match up with 10" or bigger woofers.

My 10" vifa woofers should be run at less than 500 Hz (I'm going to be running them to only 300 max with my current work in progress. Try finding a dedicated midrange that will be happy down to 300Hz, I think you will be pushing it to find much that is happy below about 600-800Hz

the other factor is that the critical freq for human voice (often debated) is between about 300Hz and 3,000 Hz so, a good midbass can handle this without the need for any crossover point in this critical range. (3000 might be pushing it a bit for a 5")....

Tony.

With this it seems like a CSS WR125s would make a great midrange. 6mm Xmax, and extension to 5khz. pair this with a good tweeter and woofer, like the Koda 8" or so and you'd have a great speaker.

[wintermute]

May seem so but if you check out the freq response graphs, it's off axis performance is not real great past 3Khz (which figures since it is a 4.5" driver).

http://www.creativesound.ca/pdf/WR125S.PDF

performance off axis is just as (more?) important as on axis. the rule of thumb is don't run the driver higher than the freq that beaming (directionality) starts to occur at, which is dependent on the diameter of the cone.

Tony.

edit: just realised that if you were refering to my 300 to 3000 Hz statement then yes I don't know that I would try and use it out to 5Khz though it's down at least 10db at 30 deg off axis at 5K.....

[Greg B]

the other factor is that the critical freq for human voice (often debated) is between about 300Hz and 3,000 Hz so, a good midbass can handle this without the need for any crossover point in this critical range. (3000 might be pushing it a bit for a 5")....

Yeah, well as you say, it's often debated. I actually prefer the more old school woofer/mid crossover of ~600-800 or so. It provides a natural solution to the baffle step for common speaker dimensions, and allows the use of a true midrange for more resolution.

AFA the critical freq, to my ears, I prefer having ~80-500 all coming from one driver. BTW, that pretty much covers the fundamentals of the human voice. Also, very generally, I prefer the sound of lower xmax true woofers.

An alternate 'modern' way of making a 3 way is to use a midwoofer for a midrange, cross lower, and use a high xmax woofer/subwoofer for the low frequencies. The advantage of this is that deeper bass can usually be achieved. The disadvantage is that it will typically be lower efficiency. The 'mid' will need BSC just as in a sub/sat design.

GB