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Multi-Way Conventional loudspeakers with crossovers

Is it possible to cover the whole spectrum, high spl, low distortion with a 2-way?
Is it possible to cover the whole spectrum, high spl, low distortion with a 2-way?
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Old 9th November 2019, 02:28 AM   #4131
mlee is offline mlee  Canada
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Quote:
Originally Posted by camplo View Post
#Random
This is the Axi2050 group delay on a 250hz jmlc
Interesting. I would have thought a jmlc would have had significant group delay in the 250hz range with the posted frequency response.
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Old 9th November 2019, 02:35 AM   #4132
camplo is offline camplo
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Considering it’s group delay is tight down to almost 100 hertz, I personally think it’s more credit due to the driver than the horn.
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Old 9th November 2019, 03:07 AM   #4133
Ro808 is offline Ro808  Netherlands
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Your own?
Above 300 Hz it starts to look (very) good, taking 4ms as a reference value.

Last edited by Ro808; 9th November 2019 at 03:20 AM.
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Old 9th November 2019, 03:14 AM   #4134
Ro808 is offline Ro808  Netherlands
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Originally Posted by camplo View Post
Considering it’s group delay is tight down to almost 100 hertz, I personally think it’s more credit due to the driver than the horn.
Yes, it looks like Mark Dodd and Jack Oclee-Brown have succeeded in creating (by far) the best Titanium diaphragm ever, including the driver around it, of course.
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Old 9th November 2019, 05:42 AM   #4135
Ro808 is offline Ro808  Netherlands
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Homage to RCA, fully horn-loaded 2-way loudspeaker system.
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Old 9th November 2019, 07:28 AM   #4136
AllenB is offline AllenB  Australia
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Quote:
Originally Posted by camplo View Post
#Random
This is the Axi2050 group delay on a 250hz jmlc
Respectfully. Your group delay magnitude scale is misleading. The extreme issue below 100Hz is irrelevant to the lower passband. Jean-Michel had a preference to cross by 300uS in the varying region, I'm sorry I cannot find a post that says this. This becomes less critical below 250Hz.
Quote:
Originally Posted by jmmlc
The main problem I see when using a driver in a frequency interval very near of the acoustical cut-off frequency of the horn is the voice seeming to come from very far inside the horn. This can be explained by the group delay that rises very fast when the frequency decreases under 2.Fc
Jean Michel on LeCleac'h horns
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Old 9th November 2019, 08:41 AM   #4137
Ro808 is offline Ro808  Netherlands
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Here's Jean-Michel Le Cléac'h's 2004 ETF presentation "Crossovers, a step further !".
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Old 9th November 2019, 10:12 AM   #4138
krivium is online now krivium  France
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While we are about group delay, i've got some question i've never seen a definitive answer about ( and i don't expect it to be but...): in the 3 lower octave range ( 20/160hz) what value of gd are considered to be below audibility threshold?
Iirc below 40hz 24/25ms being considered acceptable and something like 8ms for 80hz.
What is your take on it?

Crossing at point where gd is equal ( wrt 2 adjacent way on a design) occured to me some days ago. I never really thought about it before. Is it a design target for some of you?

Camplo Axi2050 is impressive. Do you already have one?

Last edited by krivium; 9th November 2019 at 10:28 AM.
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Old 9th November 2019, 11:02 AM   #4139
AllenB is offline AllenB  Australia
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Quote:
Originally Posted by krivium View Post
Crossing at point where gd is equal ( wrt 2 adjacent way on a design) occured to me some days ago. I never really thought about it before. Is it a design target for some of you?
Yes either that, or building up to that in a crossover can allow smooth blending over a wide range free from variations. I wouldn't necessarily say the same about time of flight delay.
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Old 9th November 2019, 11:34 AM   #4140
camplo is offline camplo
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I think this phenomenon about group delay and the lower spectrum is akin to the argument that sound below 200hz or is it 80hz, or what ever number you choose, isn’t locatable...to where this may be true for the general audience but some of us are more sensitive than others, yet more importantly, it’s just not detrimental to the experience. What happens is that even though it’s not taking away from the pleasure of audition it is changing the actual waveform and if you had a system who’s group delay within the bass was high but acceptable and direct comparison to a system with outstanding group delay performance, you will hear a difference and the system with the better group delay is more honest, so as a sound engineer you should desire the best group delay possible. I have found that with headphones I can be very meticulous with the crafting of bass compression because the group delay is so tight that I can hear the changes...amongst no room as well I guess. Group delay is to bass or signal in general as is the attack setting of the envelope. The woofer group delay at 50hz may be 25ms BUT the driver has the signal already at reference 0ms....so from 0 to 25ms it gradually reaches full amplitude, a crescendo, if you will. No different than the attack setting of the envelope. So from a purely spectators perspective maybe that’s fine, a minuet spin on the artist (engineers) original vision/intentions but, for the truest sense of critical listening, no. Am I worried about it? Not really because group delay among a lot of other things make super accurate bass production a huge (expensive) challenge, so....I have headphones for the intricate details and I use the loud speakers for level assessment. Transient response , is a somewhat controversial topic is it not, especially when talking about bass? Well group delay literally changes the transients shape from sharp to soft, the more extreme it gets.

Last edited by camplo; 9th November 2019 at 11:55 AM.
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