I don't think anything I said about crossing tweeters high on steep LR4 slopes is controversial! 
We all know this makes for lower distortion.
This MOrel CAT 298 soft-dome speaker is not rubbish. But I had to work at it.
Of course, advice depends on circumstances. A single cap horn tweeter like a Morel CAT 378, with LCR impedance correction on the Fs resonance is quite a good way to get an LR2. This has the benefit of lower excursion at low frequencies due to the horn. This must be good.
MOREL CAT 378 Soft Dome Horn Tweeter – AmpsLab
Notch filter design calculator - for speakers | Audio Judgement
Interesting to me is the CSD plot of typical tweeters like the XT25-30:
Cumulative spectral decay explained - CSD plot using ARTA
Deal with the Fs, and avoid anything below 2kHz is my takeaway.
We all know this makes for lower distortion.
This MOrel CAT 298 soft-dome speaker is not rubbish. But I had to work at it.
Of course, advice depends on circumstances. A single cap horn tweeter like a Morel CAT 378, with LCR impedance correction on the Fs resonance is quite a good way to get an LR2. This has the benefit of lower excursion at low frequencies due to the horn. This must be good.
MOREL CAT 378 Soft Dome Horn Tweeter – AmpsLab
Notch filter design calculator - for speakers | Audio Judgement
Interesting to me is the CSD plot of typical tweeters like the XT25-30:
Cumulative spectral decay explained - CSD plot using ARTA
Deal with the Fs, and avoid anything below 2kHz is my takeaway.
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Exactly! The tweeter-only distortion maybe lower, but the complete speaker distortion is not necessarily with the higher xo point.
I have heard many tweeters, although not the latest generation (everything can not), Jbl 075, Yamaha of the beryllium of the NS1000, AMT of the Ess, JVC of ribbon (rare avis, but excellent for those years, they only manufactured it for DIYs) everything is relative ..... ´, it depends on how the integration with the dedicated midrange or a mid-woofer is resolved ...
I am very happy with the integration of the Audax TW034X with the Jantzen JA8008 ....
I bet that many have not heard it either, so we are even, friends ...
In fact, all those who own it in their DIY speakers the same integration think the same! That is irrefutable !
´, it depends on how the integration with the dedicated midrange or a mid-woofer is resolved ...I am very happy with the integration of the Audax TW034X with the Jantzen JA8008 ....
I bet that many have not heard it either, so we are even, friends ...
In fact, all those who own it in their DIY speakers the same integration think the same! That is irrefutable !
Attachments
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Audax TW034X0 1.3" Textile Dome Tweeter
"
Audax TW034X0 es el reemplazo directo del viejo HD13D34H con un manejo de potencia muy mejorado y una respuesta lineal extendida. Bobina de voz de 34 mm. Utilizado por muchos fabricantes OEM como Spendor, Rogers y monitores BBC. Sin ferrofluido Este es también el tweeter de reemplazo en la parte posterior de la bocina JBL SVA 2100....... "
"
Audax TW034X0 es el reemplazo directo del viejo HD13D34H con un manejo de potencia muy mejorado y una respuesta lineal extendida. Bobina de voz de 34 mm. Utilizado por muchos fabricantes OEM como Spendor, Rogers y monitores BBC. Sin ferrofluido Este es también el tweeter de reemplazo en la parte posterior de la bocina JBL SVA 2100....... "
As an engineer, who's primary objective is to make things work better, or make them work at all, we just seek improvement. What other sensible metric is there?
I had a visit from my music and cinema-loving nephew yesterday. His tastes are strangely eclectic, being grunge metal and retro John Coltraine jazz. We tried out some stuff on these soft-dome speakers: TBH, people say I have Catholic tastes too.
This is what I call a Jazz speaker. Bit weak on complex Classical. IMO, a really good speaker has a quality of silence between the notes.
I am in the sophisticated crossover camp, myself.
I am not at all phased by complexity or build difficulty, nor is Alan Shaw of Harbeth.
This Harbeth is one of only two ways to do a three way AFAIK:
The other way uses a 4-5" mid cone.
HiFi these days is a dirt cheap hobby. You can pick up an outstanding system in the second-hand shops for about £150. That's amp, source and speakers.
I did a bit of work with an eminence 8" alpha or beta woofer and an Audax TWO-34 1.5" tweeter years back. I just stuck them in an old Wharfedale LInton box that I found in the street with some off-the-shelf second-order 2.5kHz crossover:
Needed a vent for the bass. Just how it works with Eminence. And excellent and loud!
To me, all great speakers have a mathematical correctness to them. They do SOMETHING extremely well. My friends, I must tell you that complex numbers and their focus on rotational symmetries are not the most sophisticated thing in the Universe. A mere 2-dimensional Clifford Algebra.
You don't have to look far to find far more sophisticated mathematics playing out on the 4 main moons of Jupiter: Orbital resonance - Wikipedia
I really don't know, but I wonder if it would all fall apart if you removed (the invisible Man) Callisto.
I had a visit from my music and cinema-loving nephew yesterday. His tastes are strangely eclectic, being grunge metal and retro John Coltraine jazz. We tried out some stuff on these soft-dome speakers: TBH, people say I have Catholic tastes too.
This is what I call a Jazz speaker. Bit weak on complex Classical. IMO, a really good speaker has a quality of silence between the notes.
I am in the sophisticated crossover camp, myself.
I am not at all phased by complexity or build difficulty, nor is Alan Shaw of Harbeth.
This Harbeth is one of only two ways to do a three way AFAIK:
The other way uses a 4-5" mid cone.
HiFi these days is a dirt cheap hobby. You can pick up an outstanding system in the second-hand shops for about £150. That's amp, source and speakers.
I did a bit of work with an eminence 8" alpha or beta woofer and an Audax TWO-34 1.5" tweeter years back. I just stuck them in an old Wharfedale LInton box that I found in the street with some off-the-shelf second-order 2.5kHz crossover:
Needed a vent for the bass. Just how it works with Eminence. And excellent and loud!
To me, all great speakers have a mathematical correctness to them. They do SOMETHING extremely well. My friends, I must tell you that complex numbers and their focus on rotational symmetries are not the most sophisticated thing in the Universe. A mere 2-dimensional Clifford Algebra.
You don't have to look far to find far more sophisticated mathematics playing out on the 4 main moons of Jupiter: Orbital resonance - Wikipedia
I really don't know, but I wonder if it would all fall apart if you removed (the invisible Man) Callisto.
Hi guys!
I decided to try an 18sound ND1090 + XT120 CD/horn combo. After a provisoric setup, I like what I hear. Today I did a distortion measurement and found some strange behavior at one of the tweeters.
The measurement contains the completed filter for the tweeters, acoustical LR4 at 2 kHz, their frequency responses are the same, sound level is fairly loud. There is a big difference in the harmonic distortion, I think this is not normal.
What do you think about that?
Thanks!
I decided to try an 18sound ND1090 + XT120 CD/horn combo. After a provisoric setup, I like what I hear. Today I did a distortion measurement and found some strange behavior at one of the tweeters.
The measurement contains the completed filter for the tweeters, acoustical LR4 at 2 kHz, their frequency responses are the same, sound level is fairly loud. There is a big difference in the harmonic distortion, I think this is not normal.
What do you think about that?
Thanks!
This.
Your 4KHz midrange breakup will have a 3rd order HD peak ~ 1.3KHz. Smack bang in the sensitive upper midrange.
I blamed a Seas 27TDFC tweeter for a similar problem to yours - but it is backed by a Seas L15 with nasty 2.7KHz 3rd order HD. This definitely contributed to the belief the tweeter is "peaky" on some recordings, when it was actually the L15 breaking up. Paring it with a more "muddy" peerless woofer, crossed slightly lower, flatter and with shallower slope did not have the same treble issue, confirming it was the midrange.
I'm not saying your midrange is 100% accountable. Nor the tweeter. but the combination should be evaluated. Leave yourself open to investigate problems elsewhere.
PS: Do you have any particular albums it is more apparent on? PPS: Avoid "greatest hits" and compilation albums. They seem to have the dynamic range beaten out of them with the mixing engineer prone to "amp up" the treble in the mix.
This one looks terrible:
This one, not so bad:
I think you've got a rubbing voicecoil on the first one. Simple as.
Thanks system7!
Yesterday I disassembled the bad looking unit, refitted the diaphragm carefully and the distortion became as with the other unit, the problem went gone.
But today I measured again and the problem reappeared! : D What the hell? What's going on?
The measurement is at high SPL, the lifted distortion is not recognizable by ear.
@ Dave Bullet
I'm not surprised that something was wrong with the L15's voice. Even at 90 dB there is a more than 5% HD peak in the mentioned region. My midrange driver have slightly more than 0.1% there.
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Have you tested for consistency between measurements? It is not proper to just trust a piece of equipment, the operator, the controls or the circumstances.
I am still full of 'Flu, and slightly delirious, so maybe don't take me too seriously.
But I remember a saying, that when all else fails: GIVE UP!
Seriously expensive Scan D3004/660000 tweeters here. Non-ferrofluid by the look of them. So we can't rely on the fluid centring the voicecoils and keeping them centred and non-rubbing.
Scanspeak D3004/660000 Tweeter - Illuminator Range
Why not give these a go: CHN-50 full range driver | KJF Audio
Not a load of bucks. What you gotta lose?
But I remember a saying, that when all else fails: GIVE UP!
Seriously expensive Scan D3004/660000 tweeters here. Non-ferrofluid by the look of them. So we can't rely on the fluid centring the voicecoils and keeping them centred and non-rubbing.
Scanspeak D3004/660000 Tweeter - Illuminator Range
Why not give these a go: CHN-50 full range driver | KJF Audio
Not a load of bucks. What you gotta lose?
The full quote is - "When all else fails, give up and go to the library." This was by Stephen King. Maybe he was saying that taking a step back sometimes will help to see the bigger picture?
I've been back to the library!
This is the sort of dome Morel CAT 298 thing that causes problems. Spiity and sibilant. They ALL do it!
Academia50 has made a good suggestion with his Troels waveguide idea, which works for him:
I have had to cut down another HUGE image here...
I was reading Michael Chua on dome tweeters:
Dome Tweeters – are manufacturers’ Response plots realistic? – AmpsLab
Seems to me they all have terrible diffraction problems, even on wide baffles. Horrible frequency response variations peaking at about 5kHz, which is the sibilance area.
His idea is to use waveguide tweeters:
Finch (Morel CAT378 + Vifa PL18W0-09-08) – AmpsLab
The Morel CAT 378 looks like cheap entertainment to me!
This is the sort of dome Morel CAT 298 thing that causes problems. Spiity and sibilant. They ALL do it!
Academia50 has made a good suggestion with his Troels waveguide idea, which works for him:
I have had to cut down another HUGE image here...
I was reading Michael Chua on dome tweeters:
Dome Tweeters – are manufacturers’ Response plots realistic? – AmpsLab
Seems to me they all have terrible diffraction problems, even on wide baffles. Horrible frequency response variations peaking at about 5kHz, which is the sibilance area.
His idea is to use waveguide tweeters:
Finch (Morel CAT378 + Vifa PL18W0-09-08) – AmpsLab
The Morel CAT 378 looks like cheap entertainment to me!
I'm temped to simply buying the Seas DXT tweeter to try it out myself. I would like to pair it with maybe a hard cone from seas or SB - in the 5" range. But I cant figure out if it would be better to find a waveguide for the SB BE or any of the options from this site:
Heissmann-Acoustics | Driver tests | reviews
I only believe that I like hard domes, cause I sense more refinement with these.
Right now I have a 5" Accuton and Seas Magnum tweeter, crossed at 2400hz LR4 - which works really well..... but maybe a waveguide could improve things.... hmmmm
Heissmann-Acoustics | Driver tests | reviews
I only believe that I like hard domes, cause I sense more refinement with these.
Right now I have a 5" Accuton and Seas Magnum tweeter, crossed at 2400hz LR4 - which works really well..... but maybe a waveguide could improve things.... hmmmm
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I am slightly shocked that I never figured out why some tweeters sound so terrible.
Dome Tweeters – are manufacturers’ Response plots realistic? – AmpsLab
OK, I get it now:
Once you get it, even a 5" with a waveguide makes sense:
Ergo IX 2-way DIY speaker kit | KJF Audio
Dome Tweeters – are manufacturers’ Response plots realistic? – AmpsLab
OK, I get it now:
Once you get it, even a 5" with a waveguide makes sense:
Ergo IX 2-way DIY speaker kit | KJF Audio
I think I'd just ring up those good people at SEAS in Moss and tell them to sort it out!
I have done a bit of electrical Impedance correction work on the Morel CAT378:
By the best of my estimates, we need an LCR of 1mH, 47uF and 10R here. Plus a Zobel of 7.5R and 2.2uF.
I have done a bit of electrical Impedance correction work on the Morel CAT378:
By the best of my estimates, we need an LCR of 1mH, 47uF and 10R here. Plus a Zobel of 7.5R and 2.2uF.
Attachments
Just guessing:
Maybe the tweeter manufacterers still sell dome because the whole trade off is good enough ? lenses or horms introduce perhaps different problems... looks like with a horn a tweeter has more dips & peaks ? little paper cones with aluminium mushroom at the center have also a dips and peaks spl.. while the paper perhaps the damping makes these tweeter units nice at ears - Nowadays people want to hear (and look at) the tweeters more ! B&W diamond bullet tweeters ?
Once it's measured on the bafle, whatever the difractions, the circular shape and the small pattern make it easier to marry with the mid unit... instead most of the tweeter planars with a squarred shape and higher footprint ?? Non saying those last often need 3K to 4K minimum but some expensive (bigger) units... Not sure how a little AMT or ribbon could work with a horn the apex is smaller than the emissive squared surface of the tweeter?
As said a major bad behavior in the highs due to the circular shape has been cured with many brands already if i read System7 : double ring, SBAcoustic center pitch, impregnation of soft dome with clammy material to control the break ups, eleptique cone with some Audax, cones with Focal or Davis... with more or less sucess! Not talking about the 90° eyed brandnew tweeter from ScanSpeak (Smaug is looking at you !)
There are few circular planar tweeters... HiVi. Looks like circular electrostat, ZaphAudio measurements never praised their sounding behavior if I'm corect...
I believe normalisation institutions don't change the measurement protocols for tweeters because they must be purchased by speaker manufacterer only already aware of it...not te enthusiasts market. But perhaps a 10" squarred front bafle should be the norme for tweeters instead naked or an IEC bafle ?
What are yours thoughs about ribbons (squared) with horns ? Could it be fixed with a special shape transistion patern at the apex ?
Maybe the tweeter manufacterers still sell dome because the whole trade off is good enough ? lenses or horms introduce perhaps different problems... looks like with a horn a tweeter has more dips & peaks ? little paper cones with aluminium mushroom at the center have also a dips and peaks spl.. while the paper perhaps the damping makes these tweeter units nice at ears - Nowadays people want to hear (and look at) the tweeters more ! B&W diamond bullet tweeters ?
Once it's measured on the bafle, whatever the difractions, the circular shape and the small pattern make it easier to marry with the mid unit... instead most of the tweeter planars with a squarred shape and higher footprint ?? Non saying those last often need 3K to 4K minimum but some expensive (bigger) units... Not sure how a little AMT or ribbon could work with a horn the apex is smaller than the emissive squared surface of the tweeter?
As said a major bad behavior in the highs due to the circular shape has been cured with many brands already if i read System7 : double ring, SBAcoustic center pitch, impregnation of soft dome with clammy material to control the break ups, eleptique cone with some Audax, cones with Focal or Davis... with more or less sucess! Not talking about the 90° eyed brandnew tweeter from ScanSpeak (Smaug is looking at you !)
There are few circular planar tweeters... HiVi. Looks like circular electrostat, ZaphAudio measurements never praised their sounding behavior if I'm corect...
I believe normalisation institutions don't change the measurement protocols for tweeters because they must be purchased by speaker manufacterer only already aware of it...not te enthusiasts market. But perhaps a 10" squarred front bafle should be the norme for tweeters instead naked or an IEC bafle ?
What are yours thoughs about ribbons (squared) with horns ? Could it be fixed with a special shape transistion patern at the apex ?
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