simple with 4/5cone mid you can have all !I think I do understand why.
Not everyone is aware of those proven theories, measurements and findings. We all have different levels of knowledge and drive to educate ourselves.
No different than with any hobby or subject
that's means low punch ,xmax ie power, can work with 10-12-15-18" woofer , yu have the voice ie vocal band free of xo can go up quite wel,l 3k isn't a problem some more ....modern tw can go quite low too....
drome mid is an old story...when tw cannot go low ,work fine on 8" in 3way like all old design a non sense with modern 6.5woofer
I quote Troels:
"The thing is that mating the right 8" and finding a tweeter going down to 1.5 kHz may be possible, but in the end it still sounds like an 8+1 speaker! It has a distinct character due to the large driver having to handle everything up to 1.5 kHz. The dispersion pattern may look exactly as good as a 3-way, but the sound is very, very different.
At higher frequencies the 8" driver cone also acts as a waveguide and this may count for some of the distinct sound.
Crossing over at 1.5 kHz is challenge and few dome tweeter like this - and some even require a steep 4th order filter to save it from voice coil burning. Most dome tweeters start having serious distortion when we get down below 1.5 kHz.
One way or the other, an 8" + dome is a compromise - as any other loudspeaker construction. Previously we saw numerous brands taking advantage of the 8+1, like Snell. But Snell used a very benign coated soft-cone Vifa driver. It had its strengths and weaknesses, but provided at lot of good sound for a modest price.
As you may know, I love the classic 3-way and so far,4 constructions have been made. Adding a small 3-5 inch midrange solves the issue of dispersion in upper-mid and it doesn't cost much. End of story.
There's a reason why the full-range crowd (if I can lump people into a group) are often very particular about the amplifiers they use: tubes, or Pass-style open drain / open collector "current drive" amps with a low damping factor.
When considering a wide range of frequencies and overlapping signals with potential intermodulation distortion in most music signals, a topology where current passes through the speaker as the controlled variable is just plain cleaner sounding than a topology that merely applies a force , or voltage, at either end outside of the speaker.
99.x% of speakers are dynamic, and the same known issues repeat themselves over and over: there's a voice coil floating in a magnetic gap. The gap inherently reduces the saturation of the magnet core materials, and the imperfectly magnetised parts become temporarily available (depending the signal) as core material for the voice coil. On top of that, some parts are conductive so they also act as transformer secondaries, and the transformer coupling between them is also modulated. Entire matrix tables have been developed just to organise all the different types of modulation that can occur!
I'm not saying that "voltage in, current out" is ideal or fixes everything, just because it allows a large part of the series inductance to be ignored, but it's definitely something to consider when attempting to push the limits for driving the speakers.
As above, an 8" woofer will probably have a VC with plenty of overhang for a few mm of Xmax, so the inductance won't be a fixed value. For one, the geometry will change with bass signals, and if ~1.5kHz signals are played at the same time, a large part of the voltage will be dropped across that bass-modulated inductance.
I think one thing to look out for is that changing the damping factor will change the EQ. That's no biggie. Driving the speaker to within an inch of its life will also require some common sense, like maybe a feedback resistor that is properly tuned to the capabilities of the voice coil. So if we set a safety limit for 15 ohms for an 8 ohm speaker, the current-sense resistor will also need to get hot and go up in value to prevent thermal runaway. There's loads of stuff to experiment with!
Edit:
I understand that it's drifting a bit off-topic, but I think it's particularly relevant to mid-range speakers that try to do it all:
--Stretching the bass response down,
--making the cone heavier,
--making the VC bigger to increase power handling after the Xmax is increased, and so, trying to compensate for the side-effect of reduced sensitivity. The necessary amplifier power is easily quadrupled just to make up for an easy 6dB loss. A potentially 94dB mid with a not-so-impressive 200Hz bass roll-off is changed to a "bass monster", pumping those beats all the down to 80Hz, but with only 88dB sensitivity.
When considering a wide range of frequencies and overlapping signals with potential intermodulation distortion in most music signals, a topology where current passes through the speaker as the controlled variable is just plain cleaner sounding than a topology that merely applies a force , or voltage, at either end outside of the speaker.
99.x% of speakers are dynamic, and the same known issues repeat themselves over and over: there's a voice coil floating in a magnetic gap. The gap inherently reduces the saturation of the magnet core materials, and the imperfectly magnetised parts become temporarily available (depending the signal) as core material for the voice coil. On top of that, some parts are conductive so they also act as transformer secondaries, and the transformer coupling between them is also modulated. Entire matrix tables have been developed just to organise all the different types of modulation that can occur!
I'm not saying that "voltage in, current out" is ideal or fixes everything, just because it allows a large part of the series inductance to be ignored, but it's definitely something to consider when attempting to push the limits for driving the speakers.
As above, an 8" woofer will probably have a VC with plenty of overhang for a few mm of Xmax, so the inductance won't be a fixed value. For one, the geometry will change with bass signals, and if ~1.5kHz signals are played at the same time, a large part of the voltage will be dropped across that bass-modulated inductance.
I think one thing to look out for is that changing the damping factor will change the EQ. That's no biggie. Driving the speaker to within an inch of its life will also require some common sense, like maybe a feedback resistor that is properly tuned to the capabilities of the voice coil. So if we set a safety limit for 15 ohms for an 8 ohm speaker, the current-sense resistor will also need to get hot and go up in value to prevent thermal runaway. There's loads of stuff to experiment with!
Edit:
I understand that it's drifting a bit off-topic, but I think it's particularly relevant to mid-range speakers that try to do it all:
--Stretching the bass response down,
--making the cone heavier,
--making the VC bigger to increase power handling after the Xmax is increased, and so, trying to compensate for the side-effect of reduced sensitivity. The necessary amplifier power is easily quadrupled just to make up for an easy 6dB loss. A potentially 94dB mid with a not-so-impressive 200Hz bass roll-off is changed to a "bass monster", pumping those beats all the down to 80Hz, but with only 88dB sensitivity.
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Although not an authority on speaker design, I thought i'd throw in my $0.02. I am currently experimenting with a 3 way active design for a slim tower using a 4" mid. I have tried a Visaton W100S, Monacor SPH115HQ and Monacor SPH102KEP. All sound very respectable using Rod Elliot 24db LR Xover and 4 x TDA7293 amps (Small size is king here!). I note in John Murphy's book on speaker design that in Chapter 6 he lists recommended crossover frequency and recommended upper frequencies for a variety of driver sizes, with beaming being the selection criteria. The difference between my 3 way design and my very ancient two way passive speakers with a 10" bass unit is fabulous. I'm not sure how these stand up for cone break up etc. I plan to re-use that 10" bass with a Monacor SPH135C as the midrange (Back on topic here.. )
)
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Ehh, before you go, could you please clarify what you meant - how is the difference fabulous?The difference between my 3 way design and my very ancient two way passive speakers with a 10" bass unit is fabulous.…… (Back on topic here..
With the 3 way there is a huge increase in vocal quality, it sounds much more like the vocalist is right in front of you. Other instruments like acoustic guitar sound much much cleaner and closer to Hi Fi rather than just "audio" if you follow? The old units have a very simple first order crossover and the midrange was always very compromised as a result due to excessive bass getting into the tweeter and expecting a 10" bass unit to handle high midrange frequencies well.
Thanks markbakk. I am only jumping in here for the very first time, so apologies for being slightly adrift . On using the SPH135C, (a 5" driver) I plan to cross over at 300Hz and 3.1KHz and would be interested to hear of anyone's observations and experience if they have used this driver as a pure midrange rather than the usual mid-bass configuration. I hope I'm slightly more on topic with this one!
. On using the SPH135C, (a 5" driver) I plan to cross over at 300Hz and 3.1KHz and would be interested to hear of anyone's observations and experience if they have used this driver as a pure midrange rather than the usual mid-bass configuration. I hope I'm slightly more on topic with this one!
sure , but is right on this 8+1 I build speaker for 30year and I like is work ...btw he have just done the 8+1 on this new driver
http://www.troelsgravesen.dk/Discovery-81.htmI have 8" fullrange in open baffle but my 2way scan15w-9800 are really good with vfet SE by Nelson and his 3way is quite nice http://www.troelsgravesen.dk/Revelator-851.htm
I see no problem in that. Why did you select the Monacor? While it's probably fairly OK for midrange use, you could check on the following: does an unit have shorting rings or caps (to reduce distortion on midrange frequencies), is it free from bad cone breakups within 1,5 to 2 octaves above the desired lowpass frequency and does the surround behave well at mid frequencies. Those, besides other criteria, should be considered.Thanks markbakk. I am only jumping in here for the very first time, so apologies for being slightly adrift
I find last Troels design mid Revelator a little odd at reading this driver datasheet. Just smooth as a woofer more than a 3 mm Xmax midrange. I do not know how it deals with the massive post 1k hz break up to make it flat enough to cross it with a tweeter. At least It should not be the ultimate Revelator and he already stated the best Rev. was with a coated.sure , but is right on this 8+1 I build speaker for 30year and I like is work ...btw he have just done the 8+1 on this new driver
I have 8" fullrange in open baffle but my 2way scan15w-9800 are really good with vfet SE by Nelson and his 3way is quite nice http://www.troelsgravesen.dk/Revelator-851.htm
The last speaker with him always push aways the last before...
As I have the revelator 15w8530k00 I can tell you that sound wondefull not a problem, 1k isn't a breakup that sliced cone is to control that ! SD is quite big 95cm not a problem xlin you know is one of the best speakers.......
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Looks like nearfield, suspiciously smooth. But I'm not familiar with Clio MLS...
Is the baffle step hump eq'ing 1kHz dip of factory measurement?
https://www.scan-speak.dk/datasheet/pdf/15m-4531k00.pdf
Is the baffle step hump eq'ing 1kHz dip of factory measurement?
https://www.scan-speak.dk/datasheet/pdf/15m-4531k00.pdf
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25 cm measuring distance, so no correct add-up (I really don’t see the virtues of such measurements…). It’s the new TG design.
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I linked the midwoofer instead of mid, like nicoh58 says he measured in post #133.
25cm distance in measurement doesn't tell all of baffle effect, because TG 851 has quite wide baffle. But do we know nicoh58' baffle width?
Any way, off-axis responses are needed too, to evaluate a midrange's match with the tweeter.
25cm distance in measurement doesn't tell all of baffle effect, because TG 851 has quite wide baffle. But do we know nicoh58' baffle width?
Any way, off-axis responses are needed too, to evaluate a midrange's match with the tweeter.
More about Gravesen's Revelator-851 It has this 15M http://www.troelsgravesen.dk/Revelator-851/15M-8631G00.pdf in a quite narrow trapezoid baffle. Pretty good pair!
