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Mangum 12 HO as a midrange [message #47327] Tue, 19 July 2005 10:17 Go to next message
Paul Spencer is currently offline  Paul Spencer
Messages: 4
Registered: May 2009
Esquire
After searching the forum I'm confused re: Magnum 12. Is it suitable to be used as a midrange driver? From the datasheet it looks like an excellent driver with a response flatter than many hifi mids, yet I've heard comments that it's not suitable as a mid ... It appears the cheapest HE driver I can find that has a shorting ring and flat response. Comments?

The Delta 12LF also looks good as a midrange (to me at least) ... any comments on how this driver compares?

As I understand, the off axis response of a 12" is better ...

Re: Mangum 12 HO as a midrange [message #47329 is a reply to message #47327] Tue, 19 July 2005 10:54 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18791
Registered: January 2001
Illuminati (33rd Degree)

I think the Magnum 12HO is a great midrange driver. It's what I plan to use in the 9π, designed for use with the 10π or 12π basshorns.
Re: Mangum 12 HO as a midrange [message #47330 is a reply to message #47329] Tue, 19 July 2005 11:59 Go to previous messageGo to next message
Paul Spencer is currently offline  Paul Spencer
Messages: 4
Registered: May 2009
Esquire
2 questions:

1) when you posted that it's not a good mid, were you referring to another magnum?

2) how does it compare to high end hifi drivers (Scan Speak, Seas, etc) in the fidelity department, excluding obvious advantages such as efficiency and output?

Re: Mangum 12 HO as a midrange [message #47331 is a reply to message #47330] Tue, 19 July 2005 12:01 Go to previous messageGo to next message
Paul Spencer is currently offline  Paul Spencer
Messages: 4
Registered: May 2009
Esquire
Another question - it appears similar to the Delta 12 LF, which is a lot cheaper - is the shorting ring an advantage in the midrange as well and is the Magnum significantly better than the Delta as a mid?

Re: Mangum 12 HO as a midrange [message #47332 is a reply to message #47330] Tue, 19 July 2005 13:52 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18791
Registered: January 2001
Illuminati (33rd Degree)

I don't think I ever said the Magnum 12HO was not good as a midrange. I've said several times that's what it is best suited for. Maybe you're thinking of the Magnum 15HO, because I've said it won't work as the midwoofer in a four π loudspeaker.



Re: Mangum 12 HO as a midrange [message #47333 is a reply to message #47331] Tue, 19 July 2005 14:15 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18791
Registered: January 2001
Illuminati (33rd Degree)

Shorting rings are most effective at midbass and midrange frequencies. At very low frequencies, they aren't usually large enough and at very high frequencies, harmonics are ultrasonic and can't be heard. So shorting rings are best in woofers and midrange drivers.

I can hear the difference right away. I always prefer a woofer with a shorting ring to a similar one without. If you like SET amps, you may like a midrange without a shorting ring but you'll probably still like a woofer that has one. I've heard some amps that I liked the mid to have a shorting ring and some amps that seemed to be better without one. But I always prefer the woofer to have a shorting ring, if I have a choice. Perhaps the reason is the distribution of harmonics - A woofer's harmonics would be smack dab in the vocals and a midrange's harmonics would be shifted up into the overtone range or above.

As for comparison of the two specific woofers, Magnum 12HO and Delta 12LF, there's another thing you should consider too. The Delta 12LF and the Magnum 12HO are tuned differently.

The Delta 12LF is tuned to use medium to large cabinets and is made so that it has low f3 in suitable cabinets. It's a great woofer for the price, and is suitable for a variety of applicatons.

The Magnum 12HO cannot be made to work at very deep bass frequencies. You could align a cabinet to squeeze deep bass out of it, but it's not made for that purpose. It is made to be used in relatively small cabinets that aren't required to go very deep. The designer will probably incorporate it with a bass bin that goes lower. You could also use it for a small monitor but f3 isn't going to be all that low.


Re: Mangum 12 HO as a midrange [message #47339 is a reply to message #47333] Tue, 19 July 2005 23:08 Go to previous messageGo to next message
Matts is currently offline  Matts
Messages: 359
Registered: May 2009
Grand Master
Wayne,

When you talk about the shorting ring reducing harmonics, you just mean the harmonics created by the speaker "distortion", not those in the music, right?

Matts

Re: Mangum 12 HO as a midrange [message #47341 is a reply to message #47333] Wed, 20 July 2005 04:05 Go to previous messageGo to next message
Paul Spencer is currently offline  Paul Spencer
Messages: 4
Registered: May 2009
Esquire
Thanks for the quick and detailed response!

My application: I'm looking for a mid to match up with my existing 12" subs. I'm considering 2 options:

1) sealed box mid (Q.707) crossed actively at 80 Hz
2) vented midbass getting down as low as 50 or 60 Hz

#1 allows me to stuff the box and kill the back wave
#2 will probably give me better bass as I don't think my subs are that great in the upper bass

Thoughts anyone?

Re: Mangum 12 HO as a midrange [message #47342 is a reply to message #47339] Wed, 20 July 2005 06:56 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18791
Registered: January 2001
Illuminati (33rd Degree)

That's right. Shorting rings aren't a low-pass filter. They reduce harmonic distortion by making diaphragm motion more symmetrical. The magnetic field of the voice coil adds to the fixed magnet in one direction and subtracts from it in the other direction, making a slight asymmetry of motion. One way to correct for this is to use a conductive ring in the magnet structure, acting as a shorted secondary turn. Induced EMF from voice coil energy creates an opposing magnetic field and with proper ring geometry, this field makes the forward and backward forces symmetrical.


Re: Mangum 12 HO as a midrange [message #47343 is a reply to message #47341] Wed, 20 July 2005 07:02 Go to previous messageGo to previous message
Wayne Parham is currently offline  Wayne Parham
Messages: 18791
Registered: January 2001
Illuminati (33rd Degree)

As long as the mains go down past the sub, it doesn't really matter if you choose vented or sealed. If vented, I would keep the crossover range above fh though. That sort of defeats the purpose of going vented, but deeper f3 would allow you to use the mains stand-alone on occasion.


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