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 Post subject: Re: My kinda speaker
PostPosted: July 15th, 2018, 7:18 pm 
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Location: Baltimore MD
Is that part of the magic of the Planers and E'stats that they are by nature of design they are time aligned.
Is pHase alignment is a property of the passive xover


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 Post subject: Re: My kinda speaker
PostPosted: July 17th, 2018, 11:14 pm 
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Roscoe Primrose wrote:
SoundMods wrote:

Of course Magnepans and electrostatic speakers are time-aligned by default.


Except that they're so large that they're not, unless they're curved. The top & bottom are much further (>4" for a 6' tall driver at a 12' listening distance) away than the middle... Somewhere in the garage I've got a pair of line arrays I built with 18 lousy 3" or so full range drivers, curved so they're all the same distance from the listener. Of course, the curve is only "right" for a specific listening distance, but the design of the speakers is such that it wouldn't be too hard to change the curve. Interesting, despite the lousy drivers...

Roscoe



I could be wrong on this, but I think concern over time alignment of a planar magnetic or electrostatic is mental masturbation. The vertical dispersion from any one spot on the diaphragm is so limited (except as Roscoe points out in the case of curved diaphragms) that the HF and upper mids are so rolled off, that time alignment is pointless.

Perhaps the late arriving lower frequency sounds muddy up the presentation (sort of an echo effect), but given the sound of Maggies, Carvers, Acoustats, Soundlabs, etc., the time alignment error is not an issue and not the weak point of the speakers I've heard.


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 Post subject: Re: My kinda speaker
PostPosted: July 18th, 2018, 6:40 am 
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Location: Parkville, Maryland
Pelliott321 wrote:
Is that part of the magic of the Planers and E'stats that they are by nature of design they are time aligned.
Is pHase alignment is a property of the passive xover



YUP! Years ago I had a pair of speakers that I put a lot of work in and was quite satisfied with the result. Then a buddy dropped some cash into a pair of Acoustat Model 4s.

That pissed me off. The overall coherence and "single voice performance" was not something I could attain until I got my own pair. Now with my horns I have that with better transparency and slam. It took having a pair of Quads here for repair that I was able to know where I was and where I could go with my horns.

As far as passive crossovers are concerned -- as Theil found out -- a simple first-order crossover (6-db/octave) gets you there. Other types get tricky but doable. My horns have a 12-db crossover that took some dialing in but my speakers "speak with one voice."

During the good old days of JBL they put their money into the drivers (a level of design and overall quallity not seen today) and used simple first-order crossovers to great effect.

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 Post subject: Re: My kinda speaker
PostPosted: July 18th, 2018, 8:12 am 
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Crossover slopes are like any other parameter in an audio system, a compromise. First order provides simplicity and phase coherence as long as the driver centers align with the listening position but demands a lot of the drivers as the excursion of the cone continues to increase below cutoff. This can lead to higher distortion, especially at high levels. Fortunately for JBL, their drivers behaved better than average with this out of band energy.

This from a magazine review on a Thiel speaker:

"As Jim Thiel told me, because a first-order filter doesn't attenuate as abruptly as high-order filters, a driver used with a first-order crossover has to exhibit good performance two octaves beyond the specified crossover point--i.e., in a two-way speaker with a 2.3-kHz crossover point, a tweeter must be able to handle signals as low as 575 Hz, and a woofer must be able to handle signals as high as 9.2 kHz. This is especially hard on a tweeter, producing distortion at high volume and sometimes leading to driver failure (early Thiel speakers were notorious for blowing tweeters). It may also excite the woofer's "breakup modes," or distortion-producing high-frequency resonances."

Another problem that cannot be solved by driver quality is frequency response lobing caused by the distance between the driver centers when they are both operating in the same range. That lobing is caused by reinforcements and cancellations at different frequencies due to the spacing.


You always have to make decisions as to what works for you, There is no silver bullet.


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 Post subject: Re: My kinda speaker
PostPosted: July 19th, 2018, 9:34 am 
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Location: Parkville, Maryland
tomp wrote:
Crossover slopes are like any other parameter in an audio system, a compromise. First order provides simplicity and phase coherence as long as the driver centers align with the listening position but demands a lot of the drivers as the excursion of the cone continues to increase below cutoff. This can lead to higher distortion, especially at high levels. Fortunately for JBL, their drivers behaved better than average with this out of band energy.

This from a magazine review on a Thiel speaker:

"As Jim Thiel told me, because a first-order filter doesn't attenuate as abruptly as high-order filters, a driver used with a first-order crossover has to exhibit good performance two octaves beyond the specified crossover point--i.e., in a two-way speaker with a 2.3-kHz crossover point, a tweeter must be able to handle signals as low as 575 Hz, and a woofer must be able to handle signals as high as 9.2 kHz. This is especially hard on a tweeter, producing distortion at high volume and sometimes leading to driver failure (early Thiel speakers were notorious for blowing tweeters). It may also excite the woofer's "breakup modes," or distortion-producing high-frequency resonances."

Another problem that cannot be solved by driver quality is frequency response lobing caused by the distance between the driver centers when they are both operating in the same range. That lobing is caused by reinforcements and cancellations at different frequencies due to the spacing.


You always have to make decisions as to what works for you, There is no silver bullet.


Maybe a copper bullet. :crazy:

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