MJK said:
EQ has a hidden cost. As long as you remain focused on the frequency response, you can adjust the EQ to give (sometimes) astonishingly tight response. The flipside is that you're twisting the phase as you do so.
It's instructive to note that there's little to no published information on the phase response of most commercial speakers. Full range electrostatics will sometimes brag about their lack of crossovers--which leads to much flatter phase response--but even the biggest, most elaborate systems tend to omit this information. The reason being, of course, that it's all over the map...just plain ugly. It's not too unreasonable to conclude that this is part of the explanation as to why some speakers have magic and some don't.
Full range drivers, taken by themselves, are, like electrostatics, much more 'of one mind' regarding phase. When you start adding woofers to augment the bass and/or tweeters for the treble, you are in peril of losing that "something" that a single driver can do. Solution: Use as low order crossover slopes as you can get away with, and keep EQ as low as possible. For extra credit, keep the EQ away from the crossover points between drivers, as Nelson has with the woofer, where it's all the way down on the bottom.
Grey
Excellent Grey, that is something I had not thought about.
Nelson describes his Eq as follows :
I am not an amplifier or eletronics person so I am wondering what this means. Is this a second order EQ where the gain at 20 Hz is set to be 6 dB over the original electrical signal? Or is it a shelving filter that is rolled off at 20 Hz? Passive crossover design I understand but electronic EQ is beyond my limited knowledge. I have no idea how to even construct such a device, I only work after the amp in the audio chain.
Nelson describes his Eq as follows :
I am not an amplifier or eletronics person so I am wondering what this means. Is this a second order EQ where the gain at 20 Hz is set to be 6 dB over the original electrical signal? Or is it a shelving filter that is rolled off at 20 Hz? Passive crossover design I understand but electronic EQ is beyond my limited knowledge. I have no idea how to even construct such a device, I only work after the amp in the audio chain.
From what I understand, he runs the signal through an electronic (digital?) EQ and boost the 20 hz signal by 6db. I think it's very easy to do if you have an EQ. However, I haven't used one and could be wrong.
A friend who's been working in pro-sound for years highly recommends a digital EQ / crossover, as it's easy to adjust and doesn't "suck the life" out of drivers as some say passive crossovers can.
I could be wrong, but am also curious as I often contemplate going with an EQ, like the Beringer, or a similar device, for upcoming projects.
A friend who's been working in pro-sound for years highly recommends a digital EQ / crossover, as it's easy to adjust and doesn't "suck the life" out of drivers as some say passive crossovers can.
I could be wrong, but am also curious as I often contemplate going with an EQ, like the Beringer, or a similar device, for upcoming projects.
Hi Nelson,
Is it possible to post some pics?
By the way, I have noticed that generally 2nd order crossovers seems to do a good job on OB's. Martin also prefers 2nd order, be it passive or active. Also, it seems to be common that high pass is placed at 50-100% higher frequency than LP.
What is sometimes puzzling is the fact that both the woofer and the fullranger are wired in-phase. As I got it, on second order filtes one of the speakers should be connected in the opposite polarity (assuming that amplifiers have the same phase) because of the phase inversion.
Still, this is OB world, and everything seems upside-down-inside-out.. and it works....
Regards,
Vix
Is it possible to post some pics?
By the way, I have noticed that generally 2nd order crossovers seems to do a good job on OB's. Martin also prefers 2nd order, be it passive or active. Also, it seems to be common that high pass is placed at 50-100% higher frequency than LP.
What is sometimes puzzling is the fact that both the woofer and the fullranger are wired in-phase. As I got it, on second order filtes one of the speakers should be connected in the opposite polarity (assuming that amplifiers have the same phase) because of the phase inversion.
Still, this is OB world, and everything seems upside-down-inside-out.. and it works....
Regards,
Vix
Vix said:
6db/oct = 90 deg phase dreking
12db/oct =180
18db/oct = 270
24db/oct = 360
electrical connection depends of what you wanna pair with what ........
also using physical phasing in overal picture ...... ( ya know old story - all acoustical centers must be aligned vertically ) ....... so - nice that OB is tilted back .....
Vix said:
That is true if your drivers act like pure resistors, are coincident, and have zero phase across the frequency range. Once you add in the real driver's behavior (impedance and SPL response) and locations on the baffle (OB or boxed) the polarity of the connections should be determined by measurements and/or detailed simulations. I don't think there should be a hard simple rule about the polarity of the connections for any crossover. Personally, I don't believe I have ever wired drivers using a 2nd order crossover out of phase.
I had to send my amp back for repair. I use the amp to power the Alpha 15s. I am without my H-Frames and missing them!
>>> what would be your thoughts on 2x eminence beta 15 ob with a manger fullrange
Alpha 15s on OB of some kind works with many drivers. I bet the Manger will work great!
I have been wondering how the Eminence Lil Buddy would work on an OB (with the H-frames) but worry about the bump in it's top octave.
http://www.parts-express.com/pdf/290-828s.pdf
I also wonder how it's fs of 149hz might marginalize performance.
Godzilla
>>> what would be your thoughts on 2x eminence beta 15 ob with a manger fullrange
Alpha 15s on OB of some kind works with many drivers. I bet the Manger will work great!
I have been wondering how the Eminence Lil Buddy would work on an OB (with the H-frames) but worry about the bump in it's top octave.
http://www.parts-express.com/pdf/290-828s.pdf
I also wonder how it's fs of 149hz might marginalize performance.
Godzilla
- got Buddy (not much of a bump) but no place to setup another system and not sure how it might be used passively with large OB woofer. (maybe a new thread or ask MJK at the Jordan/Goldwood thread about a quick sim) re:21" woofer - -maybe it was my flimsy 3/4" plywood U baffle and not enough patience but I did not get a good bass sound on on drums, bowed bass and cello (it would have been subjectively ok to some on electronic bass) - there was some wing modulation which could have been reduced with dowel struts from wing to wing - hopefully the wimpy lookin' GW1858 will be more musical than X21 - I had some vent noise on X21 but it was being pushed -- - what are ya guys doing to reduce baffle reaction from woofer - if thats any problem
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