Thorsten, a former member here, also used to recommended high efficiency and pro drivers for similar reasons ... and also for a decade!
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DIYHiFi.org • View topic - Current Drive, smooth speaker imped., Linear Current Speaker
Kuei Yang Wang said:
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"... the power-handling and compression characteristics of our four test monitors come under scrutiny ..."
from:
www.soundonsound.com/sos/jul02/articles/monitors2.asp
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So if that is a lie then you don't mind me posting a link to a thread where Summa wg is selling here and xover schematic of that non-summa loudspeaker ?
That's not a decades old reference. And in any case I don't think that constant current will correct the effect. If you think that it will then you may not understand it. The reason is that "constant current" means RMS current versus frequency, not instantaneous current. If it were truly "constant current", then it would have to be DC.
Maybe there are decades old references to thermal modulation - NOT thermal compression - but I have not seen any (and none have been shown here). Everybody talks about thermal compression and that's not the same thing. Thermal compression is the long term effect not an instantaneous one.
Thermal compression depends on the entire motor structure including the magnet. Thermal modulation will only depend on the mass of the coil windings and their thermal coefficients. The magnet temperature does not enter into the thermal modulation problem because it is too slow. The VC changes temp instantaneously about the mean temperature - the slow effect.
🙂 - not at all. The crossover has changed so much that I doubt it is recent, the Summa has not existed for years. And making one is more than just buying a so-called "Summa Waveguide". Do you really think that I publish everything that I do 🙄
Copies are never up to the original. If they were then the Chinese loudspeakers would be fabulous. Problem is there is more to any design than meets the eye.
I suspect that you have heard some shabby copies and that's what you base your unsubstantiated opinions on.
It is well know among my customers that kits never seem to match up to the ones that I build. That shouldn't be a surprise. That's the reason that my new design's will never be kits. It is not fair to a customer for them to think that they can make a speaker as good as I make just because they bought the parts. I always make this clear to the customer.
Take for example paint. I cannot do 1st rate paint, I am not equipped. So I sell, and encourage people to buy them assembled and tested but not finished and have them painted if they want a finish up to the quality of the sound.
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I'm not sure that this xover is something you published. It is possible that owner os Summa (while they were available) measured the values.
I have two different xovers. Tweeter on one is 18dB with 10uF and 15uF and on the other is 13uF and 18uF. It has two notch filters that hit arround 2KHz (a bit under i think) and at arround 4KHz.
But as you say, it is discontinued and no harm in letting people playing on their own.
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The xover that i have schematic for is something that you've built and put into Summa model (early or late - i don't really care about that) but my intention was just to prove that i listened Summa. Your xover, your WG with 15TBX100 and DE250. That is how i formed my oppinion on your loudspeaker, that sounds great by the way but details from 400Hz and up to about 1KHz are muddy. Your waveguide with foam phase plug is awesome sounding and is the highlight of your design.
And it is not that Summa is the only loudspeaker that has this compromise. Most of the loudspeakers that i listened where 15" is xovered too high suffer from it. I listened Tannoy Ardens, JBL 4430. Can you believe that? Yes, here in Serbia - can you imagine ? Want a picture of me in front of JBL 4355 or JBL 4345? Or in front of Oris Swing perhaps ?
And it is not that Summa is the only loudspeaker that has this compromise. Most of the loudspeakers that i listened where 15" is xovered too high suffer from it. I listened Tannoy Ardens, JBL 4430. Can you believe that? Yes, here in Serbia - can you imagine ? Want a picture of me in front of JBL 4355 or JBL 4345? Or in front of Oris Swing perhaps ?
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For a 12" driver you may want to check out the B&C 12PE32 for horns.
It has a mms of around 37gr.
John Inlow has plans using it from 100Hz to 600Hz. Check out his DIY 100Hz midbass horn link on his web site. It even has a nearly proper horn length for a 100Hz horn. I don't think you'd have to be concerned about compression!
inlowsound.com
Thanks Pooge. I'm downloading it to my PC 🙂
non-summa xover schm available via PM to everyone who asks for it. It's a nice starting point if you are into 15" two way.
Here's the pic of non-summa speakers:
http://i54.tinypic.com/wbfo2f.jpg
non-summa xover schm available via PM to everyone who asks for it. It's a nice starting point if you are into 15" two way.
Here's the pic of non-summa speakers:
http://i54.tinypic.com/wbfo2f.jpg
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That is not a Summa. I cannot attest to its performance so any beliefs that you have based on that design do not apply to my designs. They are not the same.
On this picture with suma or non-summa cabs, whatewer, I spot the another pair of cabs 🙂
I know the guy who made a crossover for Swings, upper one for coaxial mid+HF unit in horn 🙂. Mr G. Christensen listened other model with a same coaxial unit in same horn many times...
Great job done.
Gerner Christensen (first from the left) with Duelund folks at some outdoor listening session... That is how the people are meeting each other many decades ago / not at the forums... 😀
Try to find some infos on Duelund concept of crossover for 3 way sys
it is more than interesting.
.
By the way I am from another story / Alnico old school drivers, many Years
rather to say decades. And PA drivers is not my couple of tea sorry.😎
.
I know the guy who made a crossover for Swings, upper one for coaxial mid+HF unit in horn 🙂. Mr G. Christensen listened other model with a same coaxial unit in same horn many times...
Great job done.
Gerner Christensen (first from the left) with Duelund folks at some outdoor listening session... That is how the people are meeting each other many decades ago / not at the forums... 😀
Try to find some infos on Duelund concept of crossover for 3 way sys
it is more than interesting.
.
By the way I am from another story / Alnico old school drivers, many Years
rather to say decades. And PA drivers is not my couple of tea sorry.😎
.
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I don't know if one would need to adopt a four way, it depends on your intentions and design goals, but I posted a suggestion before.
If you wanted to go the typical hifi route of cones and domes and cost was no option, I'd probably go with something like...
Scan speak R3004/602010 tweeter.
Accuton C50-8-044 upper midrange.
Accuton C173-6-090 lower midrange.
AE TD12X bass.
You'd need an active xover ideally to adjust for all the differences in driver sensitivity and change the xover points to 250Hz, 800Hz, 5kHz, but that'd be pretty good imo. You could change the choice of tweeter too if you wanted, but I went with that one as it's a small flange device for closer C2C spacing to the upper mid and I like the way 1" ring radiators sound.
The other and superior option imo would be to go the wave guide route and use the largest guide you can accommodate with...
BMS4550 compression driver crossed at 800Hz.
Your choice of midrange driver.
AE TDsomethingX on bass.
I don't really see the point in going four way when you can cross a good compression driver at 800Hz that will extend all the way up to 20k.
If the 4550 wasn't so expensive I'd buy a pair and give them a go. Although I'd prefer to try the neo version instead as it is more compact/lighter.
Of course they are not the same. These are made of 4cm mdf not plastic 🙂
So one can know the drivers, xovers and neto volume of the Summa but unless you do your indian dance arround it, it is not Summa ? Yeah, right 🙂
I'm done arguing about Summa. You'll never admit it because you're to biased. The thing is that it's xover point is too high for 15" woofer with Mms 156gr. 15" woofer can't play that high without some serious compromise - Summa or not. You and you marginally different (if different at all) xovers can not change that.
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I explained few pages ago while we were still having a constructive argument.
And I explained how i tested it so anyone could try and listen for themselves.
And I explained how i tested it so anyone could try and listen for themselves.
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Looks like high pass, bandpass and low pass filters feeding a 3way.
Very standard crossover.
thanks for putting forward your thoughts.
Many parts of your ideas coincide with how I think it could be done to give a good result.
Only one point that I disagree with.
A big compression driver (2") cannot get cleanly and smoothly upto 20kHz. Even a small (1") CD can't get up there.
So a ribbon for the top one or two octaves makes it still a four way.
Many own experience of horns is disco and similarly overloaded noise. Never heard a proper HiFi CD for domestic reproduction
some rare 1.5 " CD driver go smoothly to 17-18 k hz but I never heard it !
With the BMS 4550 the big bump between 1.5 k and 5 k hz is a no go but if the EQ or horn dig it ? no ?
One thing hurt me in a traditional 3 ways with low effcienty drivers : the lack of dynamics : how to jump to 80 db to 120 DB peaks in a short time (notes attacks) with low effcienty without distorsion because of thermal limits with little 3 to 5" drivers in the mid and highs ????
I accept a trade off at home like this with the good list of 5th Element : very clear, transparent drivers with low efficienty... at the price of a flat dynamic around 80 to 90 db !
And we all know that a flat dynamic listening session is fatiguing, a little boring) and you have the temptation to increase the volume : but the dynamics do not klimb, just the volume and the distorsion ! The dynamic stay flat and just the distorsions increase because the thermal limit of the coils ! Without saying that the XO and datasheets of the drivers change also not for the best !
That 's why I 'm looking for like many a trade offs between hifi and pro driver, something more around 95 db than my 85 db of today with its a 5" multilayer aluminium cone driver in the mid which play between 125 hz and 2600 hz ! A soundstage without "true" dynamic" is just good for HIP HOP ! I have the sound stage, the clearness and smoothness but unluckily not the life of music who need a punchy mid-bass and a good and wide dynamic everywhere... The M-F curve change with high DB and we need more a middle level with short high peaks of dynamics... AT least it's better also for the health of our ears if what I read elswhere is true !
Is the 800 hz written on the marble ? If a horn is avoided unluckily for WAF or lacke of space in the living room : what about a traditionel 300 to 400 crossover at 1' from the front wall with a NEO BG 10 or 8S : around 94 DB : light and fast then a XO at 1 K hz to match the thread OP ? Below a pro driver, unluckily with fabric surrounds : more for vented enclosure and with more distorsion than a silicon surround ! (in theory of course)
I don't see any driver with high efficienty to beginn after 1 Khz but a CD à la Beyma 350? A horned TPL150 ? No because iirc : earer to 1800 hz !
With the BMS 4550 the big bump between 1.5 k and 5 k hz is a no go but if the EQ or horn dig it ? no ?
One thing hurt me in a traditional 3 ways with low effcienty drivers : the lack of dynamics : how to jump to 80 db to 120 DB peaks in a short time (notes attacks) with low effcienty without distorsion because of thermal limits with little 3 to 5" drivers in the mid and highs ????
I accept a trade off at home like this with the good list of 5th Element : very clear, transparent drivers with low efficienty... at the price of a flat dynamic around 80 to 90 db !
And we all know that a flat dynamic listening session is fatiguing, a little boring) and you have the temptation to increase the volume : but the dynamics do not klimb, just the volume and the distorsion ! The dynamic stay flat and just the distorsions increase because the thermal limit of the coils ! Without saying that the XO and datasheets of the drivers change also not for the best !
That 's why I 'm looking for like many a trade offs between hifi and pro driver, something more around 95 db than my 85 db of today with its a 5" multilayer aluminium cone driver in the mid which play between 125 hz and 2600 hz ! A soundstage without "true" dynamic" is just good for HIP HOP ! I have the sound stage, the clearness and smoothness but unluckily not the life of music who need a punchy mid-bass and a good and wide dynamic everywhere... The M-F curve change with high DB and we need more a middle level with short high peaks of dynamics... AT least it's better also for the health of our ears if what I read elswhere is true !
Is the 800 hz written on the marble ? If a horn is avoided unluckily for WAF or lacke of space in the living room : what about a traditionel 300 to 400 crossover at 1' from the front wall with a NEO BG 10 or 8S : around 94 DB : light and fast then a XO at 1 K hz to match the thread OP ? Below a pro driver, unluckily with fabric surrounds : more for vented enclosure and with more distorsion than a silicon surround ! (in theory of course)
I don't see any driver with high efficienty to beginn after 1 Khz but a CD à la Beyma 350? A horned TPL150 ? No because iirc : earer to 1800 hz !
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99.99% of the time that is an artifact of the recording, not the drivers involved. There is no direct connection between driver efficiency and "dynamics" . . . the indirect connections are generally that low efficiency speakers are typically small and underpowered, and thus limited in maximum output. If you set your gains so that 0dB fs is within the capability of the loudspeaker then the dynamic range delivered will be that of the recording. It may not be as loud as you like, but that's a different issue . . .
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