But again, this impedance peak just below 50 hz frightens me. After I have listened to sealed, aperiodic and H-frame dipole bass, the reflex enclosures loose their appeal to me more and more.
Now put a passive crossover around 100 hz to it and watch how everything gets ruined.
I like that article, it shows, that equalisation does not lead to greater power consumption, it just helps you to reach Xmax earlierElectrical and mechanical limits
Simulations show, that xmax will be reached at 90W sine wave, but in reality music signals have impulse character and content under 30 hz is very little so it should not be a concern.
Only concern is the midrange, maybe that crossed as high as possible: http://www.scan-speak.dk/datasheet/pdf/12mu-4731t00.pdf
But all proposed midranges seem small to me. Maybe a higher efficiency ''8 midrange, maybe in omnidirectional configuration. But in the omnidirectional case, the ribbon tweeter is declined as it is not symetrical and cannot be used with 360 degree reflector.
High end should be bizarre and technically advanced with typical flaws addressed. A typical flaw is the off axis energy distribution. With omnidirectional designs, typically you get falling response towards the HF, because what was beamed before, now is evenly distributed across the listening space. But the overall presence of the high frequencies in the room remains the same, because the emitted energy is the same it's just not focused at you anymore. With omnidirectional you could very conveniently mate the midrange to a tweeter with rising response and end with flat SPL response throughout.
Best Regards!
Omnidirectional 8 inch?, surely not the best choice, you would have to use a flooder style curved waveguide like the bigger Duevel's if you were doing this. I do not think Gornir is after that.
Ribbon crossed high from from a large midrange?, what mid could allow you to do that and give you smooth integration without beaming for even power response?
If you use a larger mid drive unit you would want to have as low a crossover point as possible, think large dome, cone or good waveguide.
Surely a ribbon is best used with a dedicated physically small midrange.
I would definately go closed box or Aperiodic, the linkwitz transform is great if your driver can handle the excursion but that's just me, I rarely go for ported designs.
Er... first came the idea for higher crossover and then came the omnidirectional approach as a way around the beaming. Just throwing ideas at the author, it is always better to have a list to choose and decide.
Omnidirectional designs deal with beaming and vertical directivity diagram simultaneously.
first came the idea for higher crossover and then came the omnidirectional approach as a way around the beaming. Just throwing ideas at the author, it is always better to have a list to choose and decide.Omnidirectional designs deal with beaming and vertical directivity diagram simultaneously.
LINKWITZ transform If I do a correction like that this happens to the group delay yellow line. Bleu line closed box without linkwitz correction. Looks like a avarage basreflex(yellow line).
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Another thumbs up for closed designs from me. They work well in my room and despite trying ported variants all my designs to date have ended up sealed.
I'm not saying you can't get great sounding ported boxes but in my room they consistently out performed by in general terms by sealed.
If the extension is lacking and you've got the excursion to spare then some light EQ (nothing above 10dB boost IMO) is a good compromise.
I'm not saying you can't get great sounding ported boxes but in my room they consistently out performed by in general terms by sealed.
If the extension is lacking and you've got the excursion to spare then some light EQ (nothing above 10dB boost IMO) is a good compromise.
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LINKWITZ transform If I do a correction like that this happens to the group delay yellow line. Bleu line closed box without linkwitz correction. Looks like a avarage basreflex(yellow line).
Doesn't sound like reflex bass, at all.
Hi T101, rob g and helmut,
Thank you all for your extensive suggestions and advice.
Remember that I’m not searching for an ultra-deep sub reproduction or super high max db levels ( I live in a flat).
I must also consider the WAF factor in this design in order to get it authorized by the “boss”.
To sum it up, that’s why I chosen 1 or 2 woofers and not bigger than 8”. They should be able to play down to the low 30:es with authority and without problem at a reasonable sound level.
However I haven’t decided yet which flavor of the ScanSpeak driver I will use or if it’s going to be a closed box or bass-reflex. I will play around this weekend with some simulations.
Keep up the comments; I think it’s very interesting hearing other views of the design.
Regards
/Goran
Thank you all for your extensive suggestions and advice.
Remember that I’m not searching for an ultra-deep sub reproduction or super high max db levels ( I live in a flat).
I must also consider the WAF factor in this design in order to get it authorized by the “boss”.
To sum it up, that’s why I chosen 1 or 2 woofers and not bigger than 8”. They should be able to play down to the low 30:es with authority and without problem at a reasonable sound level.
However I haven’t decided yet which flavor of the ScanSpeak driver I will use or if it’s going to be a closed box or bass-reflex. I will play around this weekend with some simulations.
Keep up the comments; I think it’s very interesting hearing other views of the design.
Regards
/Goran
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Hi T101, rob g and helmut,
Thank you all for your extensive suggestions and advice.
Remember that I’m not searching for an ultra-deep sub reproduction or super high max db levels ( I live in a flat).
I must also consider the WAF factor in this design in order to get it authorized by the “boss”.
To sum it up, that’s why I chosen 1 or 2 woofers and not bigger than 8”. They should be able to play down to the low 30:es with authority and without problem at a reasonable sound level.
However I haven’t decided yet which flavor of the ScanSpeak driver I will use or if it’s going to be a closed box or bass-reflex. I will play around this weekend with some simulations.
Keep up the comments; I think it’s very interesting hearing other views of the design.
Regards
/Goran
Did you look at the thread on 8" coaxial drivers? It's long and detailed...
A good and compact system might be an 8" coaxial crossed over to a separate 8" woofer at about 300Hz.
Closed boxes, active operation, linkwitz transform.
Frankly I was hugely surprised by the bass quality of the linkwitz pluto with its transform circuit.
I expected to sacrifice bass depth and quality going to such a small design, of course the speaker isn't capable of powerful bass at high volume in a large room but equally the bass is incredibly tuneful with all the clarity you could hope for.
Small drivers pushed hard for powerful extended bass effect in small passive designs always sounds a little false and mechanical to my ears, usually bloated ill defined bass or overt punchy speaker effects but even the best examples usually fall short compared to closed box for my ears and I have heard many, many speakers (most are of course ported boxes) in all kinds of environments.
Ported bass nearly always draws attention to the box however Reflex has worked well in some large designs. I can see why ATC tend to avoid ported designs for their smaller speakers apart from the new scm25 speaker (which might be a nice speaker to copy!).
I just want the music to appear as if through the air, no obvious machine generating the sound, drawing attention to itself. So I value even power response, low cabinet colouration, vanishing driver integration from clean sounding drive units with no obvious frequency aberrations without overblown bass and treble emphasis, this is why I have always like most electrostatic designs, this is why I like the Pluto.
I won't pretend to be an expert but If I was building a speaker for nearfield/close range listening I would look to use a treble unit that allowed as low a crossover point as possible, aim for even power response and I would want to investigate Geddes style waveguides if listening down the length of a large lounge, again with low crossover point.
Frankly I was hugely surprised by the bass quality of the linkwitz pluto with its transform circuit.
I expected to sacrifice bass depth and quality going to such a small design, of course the speaker isn't capable of powerful bass at high volume in a large room but equally the bass is incredibly tuneful with all the clarity you could hope for.
Small drivers pushed hard for powerful extended bass effect in small passive designs always sounds a little false and mechanical to my ears, usually bloated ill defined bass or overt punchy speaker effects but even the best examples usually fall short compared to closed box for my ears and I have heard many, many speakers (most are of course ported boxes) in all kinds of environments.
Ported bass nearly always draws attention to the box however Reflex has worked well in some large designs. I can see why ATC tend to avoid ported designs for their smaller speakers apart from the new scm25 speaker (which might be a nice speaker to copy!).
I just want the music to appear as if through the air, no obvious machine generating the sound, drawing attention to itself. So I value even power response, low cabinet colouration, vanishing driver integration from clean sounding drive units with no obvious frequency aberrations without overblown bass and treble emphasis, this is why I have always like most electrostatic designs, this is why I like the Pluto.
I won't pretend to be an expert but If I was building a speaker for nearfield/close range listening I would look to use a treble unit that allowed as low a crossover point as possible, aim for even power response and I would want to investigate Geddes style waveguides if listening down the length of a large lounge, again with low crossover point.
Here's an idea:
B&C 8CX21 (tweeter + midrange coaxial, crossover 2KHz where dispersion matches)
B&C 8BG51 (woofer crossed to midrange about 300Hz)
Box for 8CX21 is sealed @ 0.6 cu ft.
Box for 8BG51 is vented @ 0.6 cu ft tuned to 52 Hz. (-3dB is about 52Hz)
So, roughly 1.2 cu ft (34 liters) for the whole thing. Sensitivity of 8BG51 is 90 dB. The 8CX21 midrange is 92dB and the tweeter is 101dB, so some padding down is required.
Is there somekind of inconsistency in this? If you do not use port to assist bass performance, usually you will lose overall sensitivity and also bass driver works even harder (because of lacking helping port).
I'm also into closed designs.
I’ve done co-axials in the past, mainly with Seas drivers and to be honest they are not “my cup of tea”, so to speak.
However it looks like an interesting combination for those who like the concept.
/Goran
I’ve done co-axials in the past, mainly with Seas drivers and to be honest they are not “my cup of tea”, so to speak.
However it looks like an interesting combination for those who like the concept.
/Goran
OK, just trying to help out.
It's interesting enough for me that I'd like to try it, except that I just finished a pair of speakers!
That's the joy of our hobby. We always find something new and exciting to build.
Regards
/Goran
Is there somekind of inconsistency in this? If you do not use port to assist bass performance, usually you will lose overall sensitivity and also bass driver works even harder (because of lacking helping port).
I'm also into closed designs.
Ultimately I am more interested in how it sounds subjectively to my human ears than whether you are reducing one type of measured distortion, introducing out of phase bass notes, reducing cone excursion at one particular frequency or whatever.
Acoustic suspension, closed systems sound less false to me, they add less speaker effects to the music.
However I have yet to hear a properly designed ported speaker that sounds better with the ports bunged. They have to be designed for closed box operation in the 1st place.
I think a linkwitz transform used with closed boxes is a cracking way to get great bass quality and depth at the volumes most people are likely to running their speaker systems, just not for old rockers or tecno freaks who like to crank their systems "to 11" with consistent deep bass drone.
Did you ever try horn midhigh transducer, there is where you will find the real highend audio nirvãna I have to be honest to you.
There is a Swedish proverb that says “smaken är som baken, delad” which means freely translated “the taste is as your but-cheeks, divided”
Nowadays I don’t fancy horn sound characteristics, but for 20+ years ago I built a lot of PA stuff, mainly with JBL, Beyma, RCF and Fane driver units. However the WAF factor tends to be low on that kind of designs.
Regards
/Goran
My wife alway's complains about the speakers. Now with the big 50cm kugelwelle she somehow finds them not that ugly.There is a Swedish proverb that says “smaken är som baken, delad” which means freely translated “the taste is as your but-cheeks, divided”
Nowadays I don’t fancy horn sound characteristics, but for 20+ years ago I built a lot of PA stuff, mainly with JBL, Beyma, RCF and Fane driver units. However the WAF factor tends to be low on that kind of designs.
Regards
/Goran
Although she now complains other wifes find them ugly.My horn did not sound direct good but now after optimizing the filter it is very special no horn coloring smooth spacious sparkling sound.
An externally hosted image should be here but it was not working when we last tested it.
The gay version kugelwelle
. Germans have often no taste of color IMO they also tent to do this to thier customized cars.An externally hosted image should be here but it was not working when we last tested it.
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