Thanks for feedback Derek, I'm glad you like my little excursions and the outcome of suspending speakers
And yes - I still have a good "teacher" at hand to consult now and then..
Just to complete the *friction that is independent to velocity* chapter - IIRC the envelope also changes from exponential towards a linear decay...
Michael
And yes - I still have a good "teacher" at hand to consult now and then..
Just to complete the *friction that is independent to velocity* chapter - IIRC the envelope also changes from exponential towards a linear decay...
Michael
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duh!
PS: Thanks Derek and Michael for facts and theories about drivers "speed and quality". Your opinions are highly regarded.
You will notice that the friction between PC mouse and table will not only shorten the decay but also significantly change the smoothness of the sine movement towards a saw tooth style of movement. This is the signal distortion occurring by friction we are after.
Not that my following measurements claim to be any scientifically – lets have a look – whatever its worth....
The left row measurements are of the Beyma 12G40, the right row same for the Peerless SLS
What we see from top to bottom are measurements with decreasing level of -20 dB each.
The red trace is THD (for referece)
The blue trace is 2nd order harmonics
The purple trace is 6th (and up) order harmonics
Now - what we possibly should look out first hand, isn't absolute values of the traces shown – as this measurements are by no means calibrated at all (nor even measured in a classic manner).
What I find the interesting part is how and at what reduced SPL levels high order harmonics (the saw tooth waveform) takes over within THD
We can clearly see that at the middle row high order distortion already is dominant with the Peerless but not the case for the Beyma.
Looking at the last row – at even lower SPL values – the traces show mixed bag behaviour. The Peerless still is definitely dominated by high order distortion – whereas in case of the Beyma high order distortion falls rapidly past 1kHz.
So – this measurements partly reflect my expectations – the transition of sine wave towards saw tooth wave shape clearly is less pronounced with the Beyma though I would have expected even more difference in the middle row – the highly frequency dependant behaviour of the Beyma with exceptionally low high-order distortion past 1 kHz in the last row comes as a total surprise though,
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As low level measurements are way easier to do in the electrical domain than in the acoustical domain – I decided to measure LowSPL-distortion like we usually measure impedance.
Meaning the speaker is fed by a current source and the voltage across the speaker terminals is measured.
In this case I simply used the recommended circuit (ARTA, STEPS) where the speaker is driven by the headphone out of my Mackie ONYX soundcard via 100 Ohm resistor.
Michael
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Hi Klaus - interesting ! - but I didn't get the point - at least my two speaker samples show significant different behavior in measurements - or is it meant that way that this difference is related to differences in VC inductance? Would not make sense to me either as I look at the *relationship* of low and high order distortion (high order beginning to stick out at lowSPL)...
Maybe you remember the context where you read those statements ?
My guess would be that they refer to the *absolute level* of distortion affected by VC impedance - which is not in the focus here.
Another idea of measuring *friction that is independent to velocity* I was thinking about is to measure the decay envelope changing from exponential towards linear.
We would have to apply a DC voltage to the speaker and then remove the amp completely - seems to be too complicated to me
( also S/N most certainly would be a problem as its basically a one shot measurement )...Tho might be the amp not necessarily *must* be disconnected to get reasonable results.
Michael
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In an effort to trace down a "stick up SPL" I did a few measurements that revealed that Beyma and Peerless did differ in only 3dB where the take over of high order distortion components begins
Beyma at –24dB (roughly equal low and high order distortion)
Peerless at –21dB (roughly equal low and high order distortion)
So, together with the (measured) roughly 5dB of higher efficiency of the Beyma we get around ~ 8 dB of increase in "qauality performance" comparing the two drivers here.
Though already respectable comparing a PRO versus HiFi speaker (!) – form mere auditioning this "qauality figure" does not fully satisfy me. I'd rate the Beyma 12G40 even higher - difference should be somewhere 12~20 dB IMO...
Michael
Beyma at –24dB (roughly equal low and high order distortion)
Peerless at –21dB (roughly equal low and high order distortion)
So, together with the (measured) roughly 5dB of higher efficiency of the Beyma we get around ~ 8 dB of increase in "qauality performance" comparing the two drivers here.
Though already respectable comparing a PRO versus HiFi speaker (!) – form mere auditioning this "qauality figure" does not fully satisfy me. I'd rate the Beyma 12G40 even higher - difference should be somewhere 12~20 dB IMO...
Michael
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Measurements go crazy in this department - nothing useful as I have seen on a quick look - I guess too much interaction with resonance jumping up to equal and exceed the 100 Ohm of the "current source" (Beyma peaks at ~200 Ohm in datasheet - not measured myself) - so accuracy and resolution get lost
What I love with the Beyma is the low-mid's and mid's - tho bass is good and tight too.
Michael
What I love with the Beyma is the low-mid's and mid's - tho bass is good and tight too.
Michael
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The reason to buy a new 12" actually was, that I wanted to have an idea what "improvement" possibly could be realised compared to the Peerless in a 2-way arrangement (Manzanita with B&G NEO3 dipole horn)
When narrowing my search towards the Beyma due to its good specs, I extensively was searching the web - but strangely, I could not find a single first hand experience for the 12G40
All in all, using a extended FR 12" up to 1000-1500Hz is perfectly ok, IMO - but, you possibly better leave it in a baffle to smooth out FR past the first dipole peak (possibly going to check that out in more detail with the Manzanita concept).
With nude speakers – for now, I found the 8" working quite well up to 1000-1500Hz XO. The 12" coming in at possibly ~700-1000Hz (not finally decided yet).
Though - if you like to push it to the extreme – you end up using a 3" - 5" to safely stay with first dipole peak below 1000-1500Hz – like StigEric is doing.
Bottom line – the exceptional clean sound of nude speakers comes with a price to pay.
Michael
When narrowing my search towards the Beyma due to its good specs, I extensively was searching the web - but strangely, I could not find a single first hand experience for the 12G40
All in all, using a extended FR 12" up to 1000-1500Hz is perfectly ok, IMO - but, you possibly better leave it in a baffle to smooth out FR past the first dipole peak (possibly going to check that out in more detail with the Manzanita concept).
With nude speakers – for now, I found the 8" working quite well up to 1000-1500Hz XO. The 12" coming in at possibly ~700-1000Hz (not finally decided yet).
Though - if you like to push it to the extreme – you end up using a 3" - 5" to safely stay with first dipole peak below 1000-1500Hz – like StigEric is doing.
Bottom line – the exceptional clean sound of nude speakers comes with a price to pay.
Michael
Listen to them for a while, and get used to their sound. THEN turn back to "normal" speaker. I was shocked the first time I did that.....
Did a cool experiment yesterday... measured maximum SPL @ 25 Hz with both 2x21" H-baffles in the rear part of the room (approx 5 meter distance). Do you want to guess what SPL I got before audible distortion started to appear?
Did a cool experiment yesterday... measured maximum SPL @ 25 Hz with both 2x21" H-baffles in the rear part of the room (approx 5 meter distance). Do you want to guess what SPL I got before audible distortion started to appear?
Very impressive!
Although human's hearing is far less sensitive to low bass, I found when it's there you can detect, if only just a little, is more than enough to be very impressive. So, (slightly) less then 120 dB seems not much (compared to those 130-some dB on most pro-sound catalogs, midband), at 25Hz, I believe that's already overwhelming in reality (especially in home environment). I also believe, at 32~40Hz, it can surely blow the neighbors away, which is coming with more sense of 'sounds'.
My woofers are much smaller in Sd and far less in Xmax, so the SPL capability is inevitably much weaker. But still, I've yet to bottomed them out and the bass slams are already pretty scary when playing loud, watching movies. No, I won't do the measurement. I might be driven out of the community....
Although human's hearing is far less sensitive to low bass, I found when it's there you can detect, if only just a little, is more than enough to be very impressive. So, (slightly) less then 120 dB seems not much (compared to those 130-some dB on most pro-sound catalogs, midband), at 25Hz, I believe that's already overwhelming in reality (especially in home environment). I also believe, at 32~40Hz, it can surely blow the neighbors away, which is coming with more sense of 'sounds'.
My woofers are much smaller in Sd and far less in Xmax, so the SPL capability is inevitably much weaker. But still, I've yet to bottomed them out and the bass slams are already pretty scary when playing loud, watching movies. No, I won't do the measurement. I might be driven out of the community....
I visited Stig Erik last year, before he started hanging drivers in chains and all that.
And his system was fantastic!
And there was nothing like "too little bass" or anything. In fact, the bass was full, lifelike and not wanting, and loud enough to boot!
It was one of these few moments where I forgot there was a mechanical reproduction. His listening room without doubt also contributed in a positive manner! He played some acoustic jazz for me - with double bass. And I immediately recognized what I call the "dipole effect" (having 2x12" H baffels per side myself - and ESL63), which is to say the effect of hearing music, not loudspeakers. It is absolutely more lifelike. Going back to closed boxes of all kinds is a great turn backwards! Changing music to rock and pop and more studio polish reveals these recordings' more flat and dull and boring sound, with a rig of Stig Erik's quality!
The SPL with this set-up is something I did not consider sitting there listening. To cite Rolss Royce, "it is enough".
/RK
And his system was fantastic!
And there was nothing like "too little bass" or anything. In fact, the bass was full, lifelike and not wanting, and loud enough to boot!
It was one of these few moments where I forgot there was a mechanical reproduction. His listening room without doubt also contributed in a positive manner! He played some acoustic jazz for me - with double bass. And I immediately recognized what I call the "dipole effect" (having 2x12" H baffels per side myself - and ESL63), which is to say the effect of hearing music, not loudspeakers. It is absolutely more lifelike. Going back to closed boxes of all kinds is a great turn backwards! Changing music to rock and pop and more studio polish reveals these recordings' more flat and dull and boring sound, with a rig of Stig Erik's quality!
The SPL with this set-up is something I did not consider sitting there listening. To cite Rolss Royce, "it is enough".
/RK
Its my experience too that box speakers may sound more focused and direct, but at the cost of a much smaller sweetspot, and less "open" lifelike sound.
Since I listen a lot to classical music, I do prefer the dipole speakers way of presenting the stereo image and their relaxed, uncoloured sound.