Not exactly.
I was asked to show details of the horn variant that *I do not recommend* to use - even so measurements look very good.
Might take a while – but I do not expect any other vertical polars than would be from a direct radiator the size of the vertical opening of the horn.
Possibly you are right – but on the other hand if we look from a standpoint of tonal variation at and around listening position - things might look different – no?
At least – I strongly prefer smooth sound field *at and around axis* for usual speaker set-up (not crossed axis in front of listening position)
Michael
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As promised here is the next variant of a "beautiful swingin' speaker"
Gaussian MinPhase horn stays the same - the main improvement is a better match to the good low-SPL resolution of the NEO3W with cone speakers of veeeeery high Qms plus smooth FR and low harmonics.
Another improvements is going "nude" – meaning hanging the speakers without any baffle at all.
Last improvement is to "split power" between a 8" mid and 12" bass making up for a 2 ½ way
XO is basically the same topology, adapted to different efficiency, baffle peak and the two speaker (partly) in series.
Michael
Gaussian MinPhase horn stays the same - the main improvement is a better match to the good low-SPL resolution of the NEO3W with cone speakers of veeeeery high Qms plus smooth FR and low harmonics.
Another improvements is going "nude" – meaning hanging the speakers without any baffle at all.
Last improvement is to "split power" between a 8" mid and 12" bass making up for a 2 ½ way
XO is basically the same topology, adapted to different efficiency, baffle peak and the two speaker (partly) in series.
Michael
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Michael,
Haven't you tested a less concealing and "boxy" baffle than the first one for the SLS? I believe you were missing half the fun by immediately going nude without testing some nice cutty sark in between.
Rudolf
Michael,
Haven't you tested a less concealing and "boxy" baffle than the first one for the SLS? I believe you were missing half the fun by immediately going nude without testing some nice cutty sark in between.
Rudolf
You are most certainly right – but what I present here is just a detour project of mine to give a teaser for those who are interested in checking out "latest news".
From that background I already knew that there is something better compared to a plain baffle which is in fact to have no baffle whatsoever – its really worth a try !
Though there are obvious drawbacks to going "nude speakers", the sonic "purity" simply is an experience. To see (hear) that you can have enough bass - for home application in decent rooms size (~20m2) - from a nude 12" is fun too.
What I wanted to combine with that step up variant is also a practical demonstration to my findings regarding low-SPL distortion I've been rambling about in Stig Erik's thread.
The main reason the NEO3W and the Peerless SLS did not merge sonically in low SPL levels, I traced down to a difference in how higher order distortion take over at low SPL levels.
IMO this is a very strong indicator to a behaviour of ill sounding dampening due to "non velocity related" friction.
As its not exactly a challenge to find speakers with high Qms – it suddenly is, if you also want generally low distortion, high efficiency and smooth FR in that package too – if you then add a requirement for decent displacement on top of that, you are left with not too many choices – especially for a 6"-8" speaker.
Finally I was very happy to find the SELENIUM 8W4P at a bargain price.
Interestingly this speaker has an old fashioned linen surround – not that usual nowadays – at least not in this form.
The BEYMA 12G40 sadly isn't that cheap, but easily worth every penny IMO and gets my warmest recommendation too.
Michael
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Sorry Michael,
but I take the freedom to dig deeper into this "no baffle" thing, even if this thread is about "swinging".
And I have to admit that I hadn't noticed your change from the SLS to the Beyma. I had thought it was the same driver.
There we are! Of course "no baffle" is better than a "wrong baffle". No discussion about that. But there should be a "right" baffle size in between. That baffle would be small enough to provide constant directivity for the projected frequency range, but still wide enough to keep as much efficiency for the driver as possible. This I would call good engineering. I don't see how such a baffle could NOT be superior to "no baffle".
You may argue that your design goal is to extend every drivers frequency range up to that point where the pure driver size becomes the optimal baffle size. But I haven't seen that mentioned anywhere.
Omitting a "wrong" baffle while changing the type and number of drivers can't be any sufficient proof for the "improvements of going nude" IMHO.
Rudolf
An alternative to the Selenium would be this:
Sica Breitbandlautsprecher LP208.38/426T
Very popular among German DIYers.
BTW, there are two interesting OBs/dipoles in the current issue of the K+T:
A large OB for the Ciare CH250 with rounded edges that goes "honestly" down to 70 Hz (like I have done years ago) and an M-dipole that goes from 35 Hz to 200 Hz without any correction (I was really puzzled about that).
Sica Breitbandlautsprecher LP208.38/426T
Very popular among German DIYers.
BTW, there are two interesting OBs/dipoles in the current issue of the K+T:
A large OB for the Ciare CH250 with rounded edges that goes "honestly" down to 70 Hz (like I have done years ago) and an M-dipole that goes from 35 Hz to 200 Hz without any correction (I was really puzzled about that).
Sure ! Its on the core of the "swing approach" anyway...
There is not much I can say about other than I have previously suggested the same as you and had good results with baffles down to the size where they only perform to smooth out the notches above the first peak – which is in praxis a rectangular baffle the side width roughly the drivers diameter.
In the end my findings were that the nude speaker simply sounds "better" in the sense that there still is some coloration from a baffle.
I have not measured and have not investigated too much in that topic in terms of extra stiff or extra dampened baffles – simply because I doubt that we can make *any* baffle to act as a "local mass" – possibly not even at modest mid frequencies.
You certainly know the beautiful rice video:
http://www.youtube.com/watch?v=Zkox6niJ1Wc
taken this intuitively picture one step further, we have to think about the principle of what's going on here and how we could avoid this to happen for a baffle or box.
In the end it comes down to the simple fact that anything *has* to be elastic (to some extent). This is a universal law usually way underestimated in its impact.
This law also dictates that masses at some distance of each other *can not* be moved coherently – given one mass only gets forced – no matter how stiff and rigid you brace them. Its a matter of sound propagatin in the material and the delay involved until the "distant" mass is reached.
The direct consequence is that the reaction impulse of a speaker excited is "not in time" as well – given you attach to a "distant mass".
This makes clear (hopefully) that any "distant" mass dictates the behaviour of the speaker to some extent.
This is all pretty much the same what is common knowledge about keeping box or baffle calm - described just in other words and telling that there is no better way to avoid ill reaction forces – and thus ill movements - than to avoid any distant mass as far as possible.
Actually this is the credo of the "beautifully swingin' speakers"
Why we are so sensible as to even detect those minimal differences – no idea – I just take it as a fact and above explanations as a good starting point until someone comes along with a better thesis.
Michael
The SICA is not well enough spec's that I would trust it from scratch - but if there are people that love it, it must have something.
Its been a long while that I've been interested in whizzer cone speakers - think they generally can not (or at least could not at those times) compete to a multi way system in resolution and cleanness of the upper region.
I was looking into Ciare speakers too - they have some pretty interesting models, but in the end I was not able to find one that combined all my requests the way I liked...
Will have a look at the K+T next time in a store, thanks ...
Michael
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Strangely one finds woofers with very high Qms mostly among those with low Qts.
One of the rare OB-woofers with fairly high Qms:
http://www.ciare.com/pdf/catalogo/CS322S.pdf
Do you think one would get lower with this than with the Beyma?
One of the rare OB-woofers with fairly high Qms:
http://www.ciare.com/pdf/catalogo/CS322S.pdf
Do you think one would get lower with this than with the Beyma?
Cool project. And useful data! I'd been backing off StigErik's SPL to my listening levels and was guessing a nude 12" might work for those of us who don't need to knock the house down. From the photo it looks like your listening area is quite reflective; how much margin would you say a single 12" has and what are your listening levels? I tend to listen at conversational levels, which seem like they might be a bit higher than yours, but I've run into what seem to be driver friction problems at the low end of my listening range.
From the photo it looks like your listening area is quite reflective; how much margin would you say a single 12" has and what are your listening levels? I tend to listen at conversational levels, which seem like they might be a bit higher than yours, but I've run into what seem to be driver friction problems at the low end of my listening range.How well do you find Qms correlates with low friction?
Interesting driver. Normally I would pan it since the datasheet SPL is pretty ragged by my standards; do you find it's that rough when run nude? I'm looking at other Selenium drivers and they're all similarly ragged. But if they don't require a lot of EQ (my PC crossover would run out of CPU trying to flatten the datasheet curves out!) there are some interesting options such as the 12PW3 for those of us that don't necessarily have the budget for a 12" Beyma. 95+dB efficient drivers would help with my power amp power problem, too.
From the picture it looks like you're using StigErik's method of bolts through the driver mounting holes. I wonder if hanging the driver by the magnet as well as the mounting holes would have any audible improvement; mechanically it's certainly more stable but I've no sense of whether basket flex radiates any significant SPL.
I'm probably not the best advisor in bass extension - telling everybody that I actually EQ *down* my OB below 80Hz or so, where others push it considerably.
From specs - not *that* much difference in bass performance (reading Fs and Qts) as far as I can see...
You have to heavily EQ OB - so I would not worry about Qts anyway - with respect to bandwidth at least ...
Michael
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Well that's actually not my "listing area" but solely my "shooting area"
But you are right I like rather "life" room acoustic.
On "margin" I can't comment other that "enough to my taste" (and possibly that of neighbours too
)As said elsewhere in Stig Erik's thread – Qms is a bunch of issues that found no better place in specs – quite in contrary to Qes that is precisely defined.
Regarding Qms and sonic pattern of speakers it really is not my invention that high Qms are said to perform more life like – my contribution was to tie friction of a certain sort to that spec – which is correct only to some degree as Qms also *could* have roots in velocity dependant friction which would not compromise sound the same way.
Honestly – I have not measured the 8W4P myself.
As I use it (ala split power), the contribution to total SPL at the ragged area is only partly - so with auditioning its not really a problem I found so far
As long as the speaker sounds "realistic / convincing" - also not being picky to tonality in general.
Going active one time, more EQ'ing easily can and possibly will be done to bring out the sweetest from that little monsters...
Not that it would have considerable audible impacts IMO – why you think ? (basket flexing is mostly due to weight and only to a veeeery small degree related to movement) - but I have already shown several methods just to inspire you – here are some more :
Don't forget to make it as save as possible by additionally attaching a fragile bracing between the bolts for example
Michael
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Thanks for the detail photos!
I'd be curious to know how many dB you'd have to add to your current settings for the SPL to be flat at 40Hz, though.
Looking at this a bit more, it occurs to me that if crossed at 500Hz the 8W4P's SPL acts to reduce the amount of dipole compensation needed. Same for the Selenium 12PW3 below 250Hz. Assuming they deliver the datasheet curves when nude. I'm highly tempted to order a pair of 12PW3s to measure.
Fair enough.On "margin" I can't comment other that "enough to my taste" (and possibly that of neighbours too
I'd be curious to know how many dB you'd have to add to your current settings for the SPL to be flat at 40Hz, though.Bass is ragged anyway.
Looking at this a bit more, it occurs to me that if crossed at 500Hz the 8W4P's SPL acts to reduce the amount of dipole compensation needed. Same for the Selenium 12PW3 below 250Hz. Assuming they deliver the datasheet curves when nude. I'm highly tempted to order a pair of 12PW3s to measure.A fair number of folks mention improvements from magnet mounting drivers in box or open baffle speakers. Notably, Seigfried Linkwitz raves at some length about magnet mounting the Orion's W22EX on his site. Haven't seen any comparitive measurements, though, and I'm not well versed in how suspension and vibrations interact. It seems clear swinging a driver should significantly reduce basket vibrations, presumably to minor levels compared to any baffled speaker. But to negligible levels? I don't know.
Thanks for the detail photos!
Fair enough.
.
Actually I have not measured nor was I aiming to get bass response flat – I just was after "a good feel" bass quality and quantity – meaning - it has to present large spaces "realistically" (in the lack of a better term)
For example you should not have to wait for the organ to hit the lowest notes to realize you are in a church – but when it actually happens you have to have a feeling that its right the way its presented.
Above – for me – is both, way more important than a "flat bass" response and also not that well correlated to flat bass response.
Until I got into OB it also was something I found missing to a large extent.
As said – the whole boost to compensate for dipole fall is done by the inductor in series. On top of that I *lower* bass actively to my taste.
Ahh, that's the roots !
The whole issue is slightly put the wrong way around by that folks IMO
The level of magnet and basket movement is dictated by mass relationship.
The level of SPL radiated is dictated in conjunction with the radiating area of the distant masses.
You will find that speaker manufacturers have generally changed basket design towards a advertised "aerodynamic" optimisation.
I not quite bought in that, even the first time I heard of form ancient Dynaudio speakers.
Actually I think the lower radiating area of odd SPL caused by mass coupling resonances is the main return here
Michael
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Based on the attached I'll file you under "allergic to bass" as 0.5dB boost at 150Hz isn't much.
Unless there's an active component to the crossover which I'm missing, anyway. Nice intercept on the 12G4's dipole peak with the crossover. Implies around 15dB of equalization at 40Hz to get to flat. I suspect that much EQ would consume a decent part of your SPL margin.Yep.
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The Rms of the Selenium is only average compared to fullrangers. The Sica for example has 0.655, most of the Fostexes are in that range, too. What drives the Qms of the Selenium up is the heavy diaphragm and the high resonance frequency. For most fullrangers in contrast to pro drivers the Rms is not given so that you have to calculate it yourself.
Suspend speaker by swing is best one can do.
great ideas! especially the completely unbaffled version - very nice!
definitely free floating is the way to go:
from: SD damping feet for loudspeakers
ok! see image attached
this is not an OB - an omni - but somewhat swinging, not literally because it is rather springing but nevertheless the driver is suspended on a cushion, not attached to anything
from: Yes, there was ... - Free Online Library
for more technical description see (inter alia): Speaker apparatus equipped with means for producing complicated waveform of low frequency with higher improved fidelity - Patent 6796401
isn't Time Domains' cushion suspension, this decoupled "virtual ground", bassically the same idea?
surely it is not "to let the driver move *as easily as possibly*" because it has to fight gravitation
but is this impulse compensation by local mass (the result) exclusively dependent on letting it move *as easily as possibly* (the mean)?
because it is complete impulse compensation by local mass that is the goal if I undestand it correctly, do I?
yes, and with an omni it seems that springs are as much easy to do
I am not sure though to what extent the results can be regarded equivalent (ie. complete impulse compensation by local mass) to those got with swings
anyway, this is the approach I took up myself in my CFS because under all circumstances such decoupling seems to be better than coupling the drivers to the enclosure by means of screws or otherwise
best,
graaf
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wouldn't be such a wire spring suspension highly resonant?
resonance of gel cushion acting as a spring is very low in frequency <<20 Hz
but in the case You describe it seems that the resonance could be problematic
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