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Multi-Way Conventional loudspeakers with crossovers

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Old 3rd October 2007, 11:19 PM   #2311
mige0 is offline mige0  Austria
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Hi



Quote:
Originally posted by gedlee



I see no reason why a conventional frequency response and maybe polar response would not show the effects being claimed.

Earl, right now I have the problem to get bored by the coloration I think originates from the rubber surround of my bass.
These surrounds are really big and fairly thick as they are designed to move 20 –30 mm pp forth and back and also have to withstand the pressure building up in a vented or closed box without collapsing.

Bottom line – there is a taste of rubber in anything I play.

Subtle effects like this and maybe also the ones created by Bud's treatment would require something more advanced like kind of a sonic pattern recognition rather than " conventional frequency response and maybe polar response " measurement.

It certainly could be done.
We would need a set of patterns first – similar to that impulse responses used for room simulation by convolution.
Than something like a fuzzy logic to extract / synthesise a " typical footprint " ( for different materials for example ).
And at the end of the list for Santa Claus we order a measurement setup like the one used in GPS receivers uncovering specific signals deep in the noise.




Greetings
Michael
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Old 3rd October 2007, 11:47 PM   #2312
Brett is offline Brett
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So Mike, have you completely forsaken horns now (apart from your subs)?
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Old 3rd October 2007, 11:47 PM   #2313
mige0 is offline mige0  Austria
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Hi


Quote:
Originally posted by Magnetar



Are you going to use the Beyma or do you just want to talk about the measurement?

Which Beymas do you have? Please post the CSD measurement.

Thanks

Magnetar, no I have no Beymas in use but I am still looking for a mid OR wide range speaker that is more up to date and checked numerous manufactures spec's to get an impression of what they aim for.

If no suitable wide range speaker is available I wouldn't hesitate to break the 300 – 3 000 Hz band into two. Sadly the 8" HEMP I had in mind is out now.

High efficiency is something nice to have though not such a necessity for me as it is for Lynn.
The Beyma 8M60/N isn't that hard to get around here and is more than reasonable priced at roughly Euro 70.-.

Greetings
Michael
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Old 4th October 2007, 02:02 AM   #2314
soongsc is offline soongsc  Taiwan
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Quote:
Originally posted by john k...


I haven't looked at the other plots but don't read too much into this change in phase result. At a 96k sampling rate one sample is equivalent to about 75 degrees in phase or 0.14 inches in distance at 20 K Hz. At 48k sampling it’s twice as much. There is no way to tell if the result is due to a small change in mic to driver distance or placement of the start of the FFt window. But if the phase can be brought into agreement by adding or removing a small time delay it would be more likely than not that the result is due to a slight change in the time of flight to from mic to driver rather than some change in the driver's response.
I do not think it could be a change in window location because it was never changed, and the increment of change in each step of the process is much less than shift of one sample window in the impulse will cause.

In regards to small change in mic to driver distance, since the driver was never removed, and these cones require so much care not to damage them, it is highly unlikely that fixture shifts can occur. The only possible explanation could be that the resistance caused by furro fliud might have caused change in distance due to application and scraping pressure relocating the cone. But this cannot result in final overall change of the distance that you noted.

I think if someone does the same test and come up with different results, then it is meaningful to discuss this more.
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Old 4th October 2007, 02:28 AM   #2315
Magnetar is offline Magnetar  United States
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Quote:
Originally posted by Brett
So Mike, have you completely forsaken horns now (apart from your subs)?
After I learned about HOM's I burned all my horns.

Actually have lots of them, good, bad, great....... I had a big horn system set up most of the summer. It was one happy HOM around here.

Quote:
Originally posted by mige0
Hi

Magnetar, no I have no Beymas in use but I am still looking for a mid OR wide range speaker that is more up to date and checked numerous manufactures spec's to get an impression of what they aim for.

Greetings
Michael
Up to date IME doesn't always mean better. I still like dirty direct heated triodes, ancient field coil drivers, paper cones, the Beatles, phenolic diaphragms, carbon resistors, garden tomatoes ,ect. Up to date these days (in our capitalistic society) normally means greater profits or just pure survival against the beast. To change is not always to improve but it can teach you many lessons. I could right a book about it - I have a couple of rooms full of changes and lessons. the holy grail is right around the next corner - (like a mouse in a maze)

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Old 4th October 2007, 03:03 AM   #2316
Brett is offline Brett
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Quote:
Originally posted by Magnetar
After I learned about HOM's I burned all my horns.
Does that mean you've become a HOMophobe?
Quote:
Originally posted by Magnetar
Up to date IME doesn't always mean better. I still like dirty direct heated triodes, ancient field coil drivers, paper cones, the Beatles, phenolic diaphragms, carbon resistors, garden tomatoes ,ect. Up to date these days (in our capitalistic society) normally means greater profits or just pure survival against the beast. To change is not always to improve but it can teach you many lessons. I could right a book about it - I have a couple of rooms full of changes and lessons. the holy grail is right around the next corner - (like a mouse in a maze)

A book would be interesting even if it was just pictures of your systems as they've evolved. It's made entertaining reading over the years online.

I'm staying with HE DR's for the next few years, till I get home and have the space for some decent horns again.
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Old 4th October 2007, 03:28 AM   #2317
Magnetar is offline Magnetar  United States
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Quote:
Originally posted by Brett


I'm staying with HE DR's for the next few years, till I get home and have the space for some decent horns again.


So where did you move to and where are you from Bret?

We will be moving in the next year or so to a much smaller place. (empty nesters) That's the main reason I keep trying to connect with a smaller system. The first speakers I built (I think I was like 10 or 11) was an open baffle (couple of boards propped up in my bedroom) with drivers out of an old Magnavox console driven by an old transistor clock radio. If I'd of known better I'd of snagged the tube amp out of the console before my Dad took it to the curb...... lesson learned.
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Old 4th October 2007, 03:54 AM   #2318
Brett is offline Brett
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Quote:
Originally posted by Magnetar
So where did you move to and where are you from Bret?
I'm in Sydney for work for the next few years. My home is on the North Coast in NSW, about 800km / 500mi from where I am now. I share digs with a mate so I'm a bit space challenged here, whereas my home has a nice large open plan space for the system.

System will soon be 2x18 Beyma LX60's, 1 x 2123 and BMS4590's on one of Jack Bouska's hybrid flares. The 2123 (later possibly an 18Sound 10NDA) will be open backed and I'll experiment with the cotton damping Lynn explained earlier.
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Old 4th October 2007, 05:25 AM   #2319
CLS is offline CLS  Taiwan
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Quote:
Originally posted by mige0


......

I am also slightly concerned by the low Qms of this driver and other Beymas in general.

This is somthing I peferr to have as high as possible. All mechanical losses contribute to low Qms .
...


This is very interesting.

Here I made a simple list for a comparison of the Qms, of some drivers with various good reputations (or which get my attentions):


Woofer

Eminence Kilomax18 ...................... 14.24
Eminence Lab12 MkII ..................... 13.32
Aura NRT 18-8 ............................... 4.4
EV DL18W ..................................... 7.32
EV EVM12L .................................... 4.37
EV EVX180B .................................. 4.0
EV 30W ........................................ 2.61
McCauley 6174 .............................. 2.9
TAD TL1601a ................................. 6.8
Peerless 830500 ........................... 3.7
Daton Titanic 15 MkIII .................... 5.89
Daton IB 15 ................................... 12.08
Lambda Accoustics Dipole15 ............. 15.2
PD 2450 ......................................... 6.89
PD 2150 ......................................... 5.51
Peavey 1508-8 HE ........................... 10.6
Peavey 1808-8 HPS LowRider 18........ 8.77


Pro Midrange

TAD TM1201 ............................... 1.43
PHL 2520 (8" mid) ....................... 4.0
Beyma 8MI100 ............................ 8.5
Beyma 102Nd ............................. 10.1
B&C 8PE21 .................................. 3.8
B&C 6PEV13 ................................ 4.6
18Sound 10ND610 ...................... 7.10
18Sound 8M400 .......................... 6.2
PD PDN 12MH25 .......................... 5.81
PD PDN 10MH25 .......................... 6.22


Wideranger

Hemp FR8.0 DIYHQ ........................ 2.5
Fostex FE207 ................................ 2.64
Fostex FE206ESR .......................... 2.32
Fostex FE206 ................................ 3.73
Fostex FE167 ................................ 4.53
Fostex FE166 ................................ 3.89
Fostex FF225 ................................ 3.06
Lowther EX4 ................................. 3.11
Visaton B200 ................................. 8.39


It seems a mixed bag here.


So, Micheal,

Would you please give some more comments about those drivers concerning their Qms?

Can I see it this way: basically the higher the Qms, the better.

Or, at least it'd better be much higher than Qes by some ratio.

Or, different usage (different range) has different considerations?
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Old 4th October 2007, 09:03 AM   #2320
mige0 is offline mige0  Austria
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Hi

Quote:
Originally posted by CLS




It seems a mixed bag here.


So, Micheal,

Would you please give some more comments about those drivers concerning their Qms?

Can I see it this way: basically the higher the Qms, the better.

Or, at least it'd better be much higher than Qes by some ratio.

Or, different usage (different range) has different considerations?


CLS, impressive list indeed.

Agree, its a mixed bag, hence I asked Magnetar in detail about his sonic experience. And I definitely agree with him " Up to date IME doesn't always mean better "

No sorry, I do not have a complete theory backed up by measurement and listening tests to give you any solid advice, I just try to navigate through subtle effects that most are not aware of.
My guess here is that the higher Qms the better and also in relation to Qes as this is masking the weird effects to some degree - at least with low impedance amps and no passive crossover in between ( solid state active amping ).

Best visualisation I found on a quick google

http://www.engr.uconn.edu/~xinyu/ME2...m_appendix.doc

is in the last two pics

The linear versus exponential decay envelope is easy to see,
For the deformation = distortion of the sine wave caused by coulomb friction I didn't find a good picture. Basically it turns the sine towards a saw tooth shape IIRC .
One additional effect of coulomb friction is that the cone doesn't reach zero and maximum displacement ( you can think of it as kind of a stick slip effect ).

The basic distinction here is between the power loss / dissipating effect due to friction that is velocity dependant ( be it electrically or viscose caused ) and the power loss / dissipating effect due to friction that isn't ( coulomb style internal friction in spider and surround materials ).



Greetings
Michael
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