Looking at the curves for the 4592ND, it's hard to understand that 115dB/W/m is possible: http://bmspro.com/fileadmin/bms-dat...ssion_drivers/neodymium/bms_4592nd_t.data.pdf
Frode
Frode
angeloitacare said:
Hi again Angelo
It is any drivers behaviour to start beaming if you do not place your ears or mike within the nearfield dispersion pattern.
And we do not when we are talking horns.
Non beaming you can only retreive from very big pannel speakers and being within nearfield listening distance.
Also a ringradiator compresion drivers starts to beam at higher freqencies. All drivers does that. Natural law by physics.
A dome as well. Just look at the curves very often show on axis measurement, -30 degrees off axis and -60 degrees off axis. There you see the beaming phenomenon.
I don't know anything about Mr. Linkwitz opinions that beaming speakers are sounding bad.
As far as I know he uses open baffel bass/midrange and a beaming dome or whatelse not open baffle in the treble.
True open baffle is only acheived by full frequency range panel speakers.
I would actually not combine open baffle with closed chamber combies. The dispersion of such combinations must lead to an awkward dispersion pattern. At least not using closed chamber drivers at the higher range. Then maybe better in the deep bass, such as closed subs or deviations thereof.
Cheers
Gerner
Frode said:
Hej Frode
But those factory curves are measured in a square horn and not in the Orphean horn used in the Swings which is circular and that horn is more efficient than square horns.
I can assure you the 115db/w/m is correct. BD-Design is not lying and I can verify it hear as well with my meassuring equipment.
Additonally I have to add that those BMS freq. curves has nothing to do with how the driver is working in the Orphean horns. There are filtering differences, thanks God, and the driver has been modified inside its magnetmotor.
Those are the true facts.
Gerner
the bms 2230 horn is 50 x 55 degrees...........
still not 115db with the neo bms coax............
I prefer 40 x 90 with no breaks, or better yet 100 x 100
I bet there are reflections at every break in angle...........
http://www.soundworks-pa-shop.de/Sp....html?XTCsid=a4e5ab25a8af283b1c0f41e214c4e473
here I see the mid driver around 112db and the tweet in breakup mode at 15khz (113db, about 1-2db louder than most curve).
http://www.bd-design.nl/contents/en-us/4592ND.pdf
still not 115db with the neo bms coax............
I prefer 40 x 90 with no breaks, or better yet 100 x 100
I bet there are reflections at every break in angle...........
http://www.soundworks-pa-shop.de/Sp....html?XTCsid=a4e5ab25a8af283b1c0f41e214c4e473
here I see the mid driver around 112db and the tweet in breakup mode at 15khz (113db, about 1-2db louder than most curve).
http://www.bd-design.nl/contents/en-us/4592ND.pdf
norman bates said:
Ciao
Still no matter the horns you mention are quare-mouthed or rectangular-mouthed. They cannot be as efficient as a circular horn, as a circular horn has no corners where sound can die or cancel.
I will/can not publish my measurements as only the manufacturor has those rights. In this case.
I don't know if Bert Doppenberg from BD-DESIGN will do that so everybody can see. It is up to him to decide.
I can just confirm by words that he is not lying about the effiency of that driver in his horn.
Cheers
Gerner
gerner said:
Ciao
Still no matter the horns you mention are quare-mouthed or rectangular-mouthed. They cannot be as efficient as a circular horn, as a circular horn has no corners where sound can die or cancel.
I will/can not publish my measurements as only the manufacturor has those rights. In this case.
I don't know if Bert Doppenberg from BD-DESIGN will do that so everybody can see. It is up to him to decide.
I can just confirm by words that he is not lying about the effiency of that driver in his horn.
Cheers
Gerner
But if The Absolute Sound will once test the Swings and likely they will, or any other magazine showing curves. It will be visible there.
Gerner
gedlee said:
Yes yes Gedlee
If voltage sensitivity is used as an expression of SPL moving in and out at one meter distance or it's wattage sensitivity where the amp decides how many amperes it can spit out in a given load.
Volt x Ampere = Watt. It has been so for quite some time now hehe
The Swings show an AC impedance resitance load of 6-9 Ohm. Smoothly and without sudden peaks or dips. Nice load for most amps.
Gerner
gedlee said:
I don't see that either is any more ambiguous than the other. dB/W/M is based (or supposed to be based) on the power dissipated by the resistance of the VC. Namely,
P = V^2/Re
Reputable driver manufactures seem to follow this. So there is a one to one correlation.
V = sqrt(P x Re).
If you want to go to dB/2.83v/M then just add
20 Log( 2.83/V) to the dB/W/M value.
Example: if Re = 16 then for 1 watt V = 4 and referenced to 2.83v the sensitivity goes down by 20 Log (2.83/4) = -3dB.
What is ambiguous is specifying on axis sensitivity without the directivity index.
What I do like is statements like:
I guess it's ok to bury that extra 15dB of power in the speaker and claim a bloated sensitivity. It's sort of like putting a 300 HP V8 in the trunk of my Miata and claiming I’m running 12 sec ¼ miles with a car that has only a 150 HP 4 cylinder engine.
John
The reality is that using watts involves assumptions about the impedance and unstated assumptions are always dangerous things. The use of voltage does not make any assumptions at all and hence is unambiguous in all cases.
Even the AES standards group is now recommending the change from "watts" to "volts" for this exact reason. They are even recommending that amplifiers be rated in volts not watts as this is what they deliver. If amplifiers were rated in volts and speaker sensitivity likewise in volts then there could never be any ambiguity as there is now.
The reality is that using watts involves assumptions about the impedance and unstated assumptions are always dangerous things. The use of voltage does not make any assumptions at all and hence is unambiguous in all cases.
Even the AES standards group is now recommending the change from "watts" to "volts" for this exact reason. They are even recommending that amplifiers be rated in volts not watts as this is what they deliver. If amplifiers were rated in volts and speaker sensitivity likewise in volts then there could never be any ambiguity as there is now.
serenechaos said:
Hi Robert.
Inside that driver is a cavity that sees another cavity. This has been blinded and closed. Should not be there.
The mod is not related to lets say colors, but to stop the driver from shouting and honking in this given horn of BD-Design. Furthermore it has reduced distortion very much and you can crank them up to their full potential in producing SPL without it freaks out and starts yelling at you.
Your ears will collapse and distort far before the horns reach their limits.
As for the next question to come:
Are the horns still equiped with that crappy filter comming from a out of box BMS driver?
Nope. Of course not. That BMS filter is absolutely useless.
That is kicked out and a very suffisticated filtering technology where applied resulting in each driver, measured on the acoustical side, is showing the same phase turn for all drivers, at all frequencies at all times. Then we have a pistion. In other words, as an example, the treble driver at any frequency you may see on your plot have exactly the same acoustical phase turn as the midrange and the bass.
So all drives moves at all the frequency spectrum hand in hand = AS ONE PISTON. A true almost point source real fullranger.
If we make speakers with uneven acoustical phase turn and let one driver try to recover what the next driver is failing to do, it doesn't work good. Fog all over the place and headache too.
Such a speaker might show a flat freq. responce curve. But how was that acheived? Any one can make that.
The importance is hidden in the *HOW* and not in the *WHAT*
At least I can tell you my brain reacts to uneven phase turn like I was stung by a bee at my most sensitive body part. Then I run screaming away.
Not many manufacturors are aware of the above mentioned reallities and among other smart solutions on that Swing
speaker which were apllied and well thought over is resulting in a wonderful pearl in my eyes.
Gerner
john k... said:I don't see that either is any more ambiguous than the other. dB/W/M is based (or supposed to be based) on the power dissipated by the resistance of the VC. Namely,
P = V^2/Re
Reputable driver manufactures seem to follow this. So there is a one to one correlation.
V = sqrt(P x Re).
If you want to go to dB/2.83v/M then just add
20 Log( 2.83/V) to the dB/W/M value.
Example: if Re = 16 then for 1 watt V = 4 and referenced to 2.83v the sensitivity goes down by 20 Log (2.83/4) = -3dB.
What is ambiguous is specifying on axis sensitivity without the directivity index.
What I do like is statements like: Quote Gerner:* bury 15 db spl from an internal amp*:
I guess it's ok to bury that extra 15dB of power in the speaker and claim a bloated sensitivity. It's sort of like putting a 300 HP V8 in the trunk of my Miata and claiming I’m running 12 sec ¼ miles with a car that has only a 150 HP 4 cylinder engine.
Gerner: Yes John....
Just to clarify everything:
The way the gain is acheived for the bass section in the Swings is that a line level filter is stealing its signal from the main amps speakers terminals, and after having done this sin, it feeds the bass amp you find inside the stand or foot.
The top horns sees only the main amp.
That internal amp is a special design for bass mainly, a GainClone amp., if it matters. But it were found neutral and good enough to just reflect what signature the choosen main amp have to offer in the bass. It is designed just for that purpose to pass on what the main amp has to tell us and with focus on: *It must sound like an amplifying cable*
Not more complicated than that. So the main amp sees into a 115db/w/m speaker: this is what a measuring amp and a mike will show you...also in the bass. The total freqency curve is flat seen from the mikes side and our ears.
Gerner
Interesting Forum
This is actually a very interesting Forum here.
Full of self learned developers who often show much higher knowledge than pro. companies developers. They might of commercial reasons, not being allowed to throw their heart into their jobs. Even they know better. (In some cases hehe).
It is so with the the plummer repairing one thing and destroying three things resolving the first problem.
It's nice to be here...guys...
Gerner
This is actually a very interesting Forum here.
Full of self learned developers who often show much higher knowledge than pro. companies developers. They might of commercial reasons, not being allowed to throw their heart into their jobs. Even they know better. (In some cases hehe).
It is so with the the plummer repairing one thing and destroying three things resolving the first problem.
It's nice to be here...guys...
Gerner
gerner said:
Not more complicated than that. So the main amp sees into a 115db/w/m speaker: this is what a measuring amp and a mike will show you...also in the bass. The total freqency curve is flat seen from the mikes side and our ears.
Gerner
Well I think this is exactly what Earl was getting at. You have no idea what power is delivered to the speaker. What you have is a speaker which has a sensitivity of XX dB/V/M. where V is the voltage applied across the speaker terminals. What current the speaker draws vs frequency is V/Z = I, and the power into the speaker is the real part of IV, and will usually have a significant variation with frequency. After all, most speakers are designed to have flat response when driver by a constant amplitude voltage source. I'm sure the swing is as well. Go back and vary the input voltage vs frequency so that 1w is always dissapated by the speaker at any frequency and the frequency response will be very different.
Speakers are intended to be voltage drivern devices and voltage sensitivity is what makes sense. The majority of driver manufactures quote voltage sensitivity today. As I noted to Earl, those driver manufactures which quote db/w/m are simple using a different reference voltage. Rather the 2.83v ( the equivalent of 1W into 8 ohms) they typically drive the driver with a voltage amplitude which would deliver 1w into a load equal to the DC R of the driver, Re. If they were to actually keep the input power at 1 w vs frequency the frequency response data supplied by the manufactures would poorly represent the driver's response.
Earl's commnets with regard to a speaker ( with x-o etc) where the impedance varises all over the place is quite another issure.
But in reality I view this as all semantics because I believe that when anyone says db/w/m what they are really trying to convey is the SPL when a speaker is driver with a voltage which would result is 1 W dissipated is some unspecified reference resistance.
gerner,
thanks for all the answers!
I didn't know the BMS was shouty and honky as it came.
Or about the factory cross-over.
I guess they really are not a good piece to start experimenting with!
And I sure didn't know the bass section had a seperate amp hidden inside, and was eq'ed up to meet the mids and highs!
So that's how it all works...
And yes, it does work great on e.g. very dynamic percussion.
Bert had this really great percussion track by someone (Osmosis? something like that) that was just unreal--
I've never heard a loud speaker come close to being able to reproduce drum hits like that before.
I went back the next day and ask him to play it again, just because I wanted to hear it again...
thanks for all the answers!
I didn't know the BMS was shouty and honky as it came.
Or about the factory cross-over.
I guess they really are not a good piece to start experimenting with!
And I sure didn't know the bass section had a seperate amp hidden inside, and was eq'ed up to meet the mids and highs!
So that's how it all works...
And yes, it does work great on e.g. very dynamic percussion.
Bert had this really great percussion track by someone (Osmosis? something like that) that was just unreal--
I've never heard a loud speaker come close to being able to reproduce drum hits like that before.
I went back the next day and ask him to play it again, just because I wanted to hear it again...
john k... said:
Hi again John... yes and no.
If the driving amp is sensitive to AC impedance that it dances with, it's is not so.
Just one example. I had a T-amp going here for a try. A Red Wine amp. Rather similar as a tube amp would react. Those amps are very sensitive to spitting out variating voltage seeing different AC impedances from the speaker load. And that is reflected in the frequency plot enourmously. They live better with a flat Ohm speaker.
A rise of 3 Ohms smoothly resulted in an SPL output of 10 db peaks all spread along the way when an AC inpedance change in a given speaker! Measured with a mike for spl ourput.. And certainly not contributing to a wished freq. flatness.
So if I know what the amp is capable off, I also know what is the result of voltage efficiency. As well as th V x A outcome.
Half impedance double up in Amperes. U know = Wattage efficiency.
Cheers
Gerner
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