I am uncomfortable doing any of these regardless if it is passive speaker level, active or passive line level or in DSP.
DSP is may be the least problematic to me but I really like to keep all and any processing of the signal to an absolute minimum.
It's a bit of a dogma with me. ;-)
The "vocal range" midbass design philosophy with 80-100Hz to 1100-1400Hz coverage.
The ISO226 sensitivity graph shows that the 3.5KHz region is the most ear sensitive, and although ~1.4KHz is more sensitive to the ear than lower frequencies, there is a plateau in this region that makes it a good choice for standard midbass-tweeter Xovers.
Physics requires that any source which is Constant Directivity cannot also have a flat on axis frequency response at the listener, so flat response controlled directivity designs that narrow the polar response with increasing frequency are popular.
Home Theater: 360degree bass --> 180degree at the baffle step --> 90degree at tweeter Xover frequency; --> 40degree for 10K-20K tweeter physical size beaming.
===================
WIKI: Vocal range is the measure of the breadth of pitches that a human voice can phonate. The most common application of the term "vocal range" is within the context of singing, where it is used as one of the major defining characteristics for classifying singing voices into groups known as voice types.
The following are the general vocal ranges associated with each voice type using scientific pitch notation where middle C=C4. Some singers within these voice types may be able to sing somewhat higher or lower:
Soprano: C4 – C6
Mezzo-soprano: A3 – A5
Contralto: F3 – F5
Tenor: C3 – C5
Baritone: F2 – F4
Bass: E2 – E4
In terms of frequency, human voices are roughly in the range of 80 Hz to 1100 Hz (that is, E2 to C6) for normal male and female voices together.
Fundamental Speech frequency
The voiced speech of a typical adult male will have a fundamental frequency from 85 to 180 Hz, and that of a typical adult female from 165 to 255 Hz.
The ISO226 sensitivity graph shows that the 3.5KHz region is the most ear sensitive, and although ~1.4KHz is more sensitive to the ear than lower frequencies, there is a plateau in this region that makes it a good choice for standard midbass-tweeter Xovers.
Physics requires that any source which is Constant Directivity cannot also have a flat on axis frequency response at the listener, so flat response controlled directivity designs that narrow the polar response with increasing frequency are popular.
Home Theater: 360degree bass --> 180degree at the baffle step --> 90degree at tweeter Xover frequency; --> 40degree for 10K-20K tweeter physical size beaming.
===================
WIKI: Vocal range is the measure of the breadth of pitches that a human voice can phonate. The most common application of the term "vocal range" is within the context of singing, where it is used as one of the major defining characteristics for classifying singing voices into groups known as voice types.
The following are the general vocal ranges associated with each voice type using scientific pitch notation where middle C=C4. Some singers within these voice types may be able to sing somewhat higher or lower:
Soprano: C4 – C6
Mezzo-soprano: A3 – A5
Contralto: F3 – F5
Tenor: C3 – C5
Baritone: F2 – F4
Bass: E2 – E4
In terms of frequency, human voices are roughly in the range of 80 Hz to 1100 Hz (that is, E2 to C6) for normal male and female voices together.
Fundamental Speech frequency
The voiced speech of a typical adult male will have a fundamental frequency from 85 to 180 Hz, and that of a typical adult female from 165 to 255 Hz.
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I appreciate that. To be honest I had significant doubts about using passive delay networks until I tried and couldn't put my finger on anything to complain about. Doesn't stop me from avoiding it though.
-that 1.4 kHz also provides about 3 inches of safe "distance" for a nicely integrated lobe between acoustic centers (for 1.4 kHz). (..largely negating combing issues with linearity.)
Near-ideal if it weren't for excursion demands on the tweeter. 😱
Avoiding is a good move IMO.
During my time as a Tannerd I've come across a passive delay circuit Tannoy used to time align their K series based monitors which they called 'SyncSource'.
It does smear detail and many who own these monitors removed that circuit because of it. Even Tannoy's own engineers freely admitted that the time alignment circuit was forced upon them by the marketing department and that in this case the cure was worse than the original 'problem'.
I think that in the case of Tannoy the problem is made worse by the fact that the woofer part (<1200Hz) is delayed and got the feeling that it would be less audible if it were the tweeter.
Either way it put me off passive delays for good.
-that 1.4 kHz also provides about 3 inches of safe "distance" for a nicely integrated lobe between acoustic centers (for 1.4 kHz). (..largely negating combing issues with linearity.)
Near-ideal if it weren't for excursion demands on the tweeter. 😱
Hi,
With any slope ? 6 dB; 12 dB : not too width filter interaction (more than one octave) near the Mundson Fletcher sensibility aera ? With 24 dB slope, we are if I don't mistake, with one octave of overlapping to around 2800 hz ! near the max sensivity of the ears... Maybe some designer XO in a null/ hole of the curve to allow less db spl in the F3 (F6) point ?
I always ask myself if the drivers allow two good choice like 700 K hz or 1400 K hz what was the best trade offs of the two filters ?
Better with an assymetric XO with 1400 hz ?
Are the lobbyng from some drivers depend of the cone diameter or also about its Sd and cone expansion profile (I was thinking to the 12" Beyma 12P80nd some are XO above 1200 which is theoricaly impossible for a width beaming at such frequencies for a 12") ?
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Eldam,
Cone profile has very little impact on beaming, which is directly linked to driver diameter.
TMM has made a most relevant remark in #11. Therefore, the choice of the xover frequencies can be based on technical considerations only. In order to maintain constant directivity, crossing over as low as components can comfortably handle is recommended, on the whole.
Cone profile has very little impact on beaming, which is directly linked to driver diameter.
TMM has made a most relevant remark in #11. Therefore, the choice of the xover frequencies can be based on technical considerations only. In order to maintain constant directivity, crossing over as low as components can comfortably handle is recommended, on the whole.
As vacu said cone diameter is by far the most important factor when it comes to beaming.
Generally a cone beams at 90º when wavelength equals diameter.
For a 12" that happens to be around 1200Hz. If the tweeter has a wider dispersion at that frequency you'd really want to cross lower. Conversely if the tweeter has a narrower dispersion you should cross higher.
Unfortunately I've never worked it out beyond that in detail.
Mostly because I'm lazy, it is easy to remember as it is, I think 90º is a good choice in 99% of all domestic applications and most waveguides and a plethora of horns are 90deg jobs anyway.
Since you mentioned Beyma the obvious one that comes to mind is the TPL-150H at 80º.
No idea where one should cross it to a 12" but I suspect 1400-1600Hz to match dispersion.
Generally a cone beams at 90º when wavelength equals diameter.
For a 12" that happens to be around 1200Hz. If the tweeter has a wider dispersion at that frequency you'd really want to cross lower. Conversely if the tweeter has a narrower dispersion you should cross higher.
Unfortunately I've never worked it out beyond that in detail.
Mostly because I'm lazy, it is easy to remember as it is, I think 90º is a good choice in 99% of all domestic applications and most waveguides and a plethora of horns are 90deg jobs anyway.
Since you mentioned Beyma the obvious one that comes to mind is the TPL-150H at 80º.
No idea where one should cross it to a 12" but I suspect 1400-1600Hz to match dispersion.
To continue where our Brummanian friend left off.
Once the wavelength of the reproduced frequency becomes smaller than the circumference of a driver (that is, enters the piston band), there will be a halving of the beam width per octave. A 12" diaphragm enters the piston band @ 360 Hz. For 90 degrees, you need to halve the 360 degrees twice, so you need to go two octaves above 360 Hz, giving you 1480 Hz. However, no 12" driver has a 12" cone, so with that compensation made, 1200 Hz is a good bet.
Have fun calculating if your speakers do it right.
Once the wavelength of the reproduced frequency becomes smaller than the circumference of a driver (that is, enters the piston band), there will be a halving of the beam width per octave. A 12" diaphragm enters the piston band @ 360 Hz. For 90 degrees, you need to halve the 360 degrees twice, so you need to go two octaves above 360 Hz, giving you 1480 Hz. However, no 12" driver has a 12" cone, so with that compensation made, 1200 Hz is a good bet.
Have fun calculating if your speakers do it right.
thanks guys for the good tips 🙂
Ok 90° for each driver ! I just looked at the drivers curves at 45 or max 60°... ! Difficult to measure a driver before buying it 🙄 (few brands give a polar map !). And a 12" in my mind was max 800/900 hz for a XO !🙁
It's almost easier to choose a driver for an OB
( Charles you read in my mind,I had a close look at Angeloitacare thread with those two Beyma. and I found odd a XO at 1600 hz could work. Your input about this AMT explains that... In theory I would had chose a 8" here.
Mundorf makes a huge AMT dipole with a possible X0 at 1800 hz (12db slope).... not as low than the Beyma !)
Ok 90° for each driver ! I just looked at the drivers curves at 45 or max 60°... ! Difficult to measure a driver before buying it 🙄 (few brands give a polar map !). And a 12" in my mind was max 800/900 hz for a XO !🙁
It's almost easier to choose a driver for an OB
( Charles you read in my mind,I had a close look at Angeloitacare thread with those two Beyma. and I found odd a XO at 1600 hz could work. Your input about this AMT explains that... In theory I would had chose a 8" here.
Mundorf makes a huge AMT dipole with a possible X0 at 1800 hz (12db slope).... not as low than the Beyma !)
Id avoid at all cost a xo in the 2 to 5khz.
imo, midrange is certainly not over 2khz.
imo, midrange is certainly not over 2khz.
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I'm sure it's just a matter of degree 😀 , amongst other things of course. Other ways to achieve the same outcome.
12" examples from Augerpro (Brandon's) Drivervault website:
https://sites.google.com/site/drivervault/driver-measurements/tang-band-75-1558se
-in order:
AE Speakers TD12M, B&C 12HPL76, Eminence Kappalite 3012HO, FaitalPRO 12PR300, GPA/Altec 414 16ohm
Red = 0 degrees, Green = 20 degrees, Blue = 40 degrees. The differences in directivity are largely due to cone-profile among these 12" drivers (..though note that they are not all the same diameter either).
https://5e8772ee-a-62cb3a1a-s-sites...r-rLU84SZ6yoIFDyqHpuEY6whyeA==&attredirects=1
https://5e8772ee-a-62cb3a1a-s-sites...8tQydX2cW9FLCBE5LsK8ssTkzI7w==&attredirects=1
https://5e8772ee-a-62cb3a1a-s-sites...zevK3ZwPnKp0LNLLSLvW8-BBtsxzpN&attredirects=1
https://5e8772ee-a-62cb3a1a-s-sites...djT--JmnKibBuVTEO3OcM-pfYwVw==&attredirects=1
https://5e8772ee-a-62cb3a1a-s-sites...rzYsXF4w6d_Tney6Hz7pobrtRc5w==&attredirects=1
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Yamaha makes some PA horns that cover the 800-20k range.
I have a pair but they are in storage right now, was thinking of using them and a pair of eminence 15" alpha open baffle design
some here http://www.usspeaker.com/hfcompressiondrivers-1.htm
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A 15" driver used as a monopole can match the directivity of a horn around that frequency. I don't know how it would be as a dipole, it has been done though.
And I'm sure it would be very costly 😎
What are the "minimum" drivers [mid and/or tweeter] that can fulfill this requirement of yours? ScanSpeak 10F?
Please note that the ScanSpeak is a three incher so there will still be a little dispersion matching issue when crossed at 5 kHz but a little engineering will solve the issue.
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1999hz is OK, then. On-axis, of course. 😛
''have you heard it, mate?''
- what ?
'' that &*%! shifted to 2000hz, didnt you notice??''
- ohh, yeaah, i ear it now! Damn, it's sooo horrible, turn that off! TURN THAT OFF NOW!!
Eldam,
I was too quick, Charles Darwin is right that the -6dB angle of a 12" driver is 1200 Hz @ 90 degrees or so. However, an opening angle of 90 degrees is way too small for living room purposes. -6dB at 180 degrees would be more like it, so I would never cross it over higher than 600 Hz. As a matter of fact, I would only use a 12" in a three way, crossed below 300 Hz.
As to your point that most drivers don't give polar maps, as I tried to imply, that is not necessary. The polar map will depend on the diameter of the driver diaphragm, and you can calculate the rest yourself following some simple rule.
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