Subwoofer Tests - Fall 2007

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No problem.:)

These ones seem less intuitive than your later ones, which is presumably why you changed:

bk%20monolith%20pc.png


At the time I couldn't access the results, I tried DVD Plaza and failed there too. Hence my idle speculation.;)

Anyway, what's keeping you?:D

Russell
 
Why does that not surprise me.:rolleyes:

I can make sense of it, sure, but I don't think it's the clearest way of showing that there is 20dB between the top and bottom sweeps. It disguises the actual difference in SPLs that were generated. I presume Ilkka agrees, or he wouldn't have changed.

Think about how clearly the newer charts demonstrate Velodyne DD servo compression for instance. Inpsite of the -3dB quoted extension at 85dB, the newer charts provide a clearer representation of why a DD12 at 100dB is actually has a -3dB of 32Hz.

And before you point it out, yes I realise it's the other bloke that's actually tested the DDs.:)

Russell
 
Why does that not surprise me.:rolleyes:

I can make sense of it, sure, but I don't think it's the clearest way of showing that there is 20dB between the top and bottom sweeps. It disguises the actual difference in SPLs that were generated. I presume Ilkka agrees, or he wouldn't have changed.

Think about how clearly the newer charts demonstrate Velodyne DD servo compression for instance. Inpsite of the -3dB quoted extension at 85dB, the newer charts provide a clearer representation of why a DD12 at 100dB is actually has a -3dB of 32Hz.

And before you point it out, yes I realise it's the other bloke that's actually tested the DDs.:)

Russell
Ok, it seems that there is a bit of a confusion. During rounds 1 and 2 I was using a 3 dB increment between the sweeps, not 5 dB like afterwords. So therefore I couldn't use the same way of presenting the power compression. Also one has to ALWAYS look at the basic "maximum output" graph in order to understand the "power compression" and "THD" graphs. Only the maximum output graph shows the absolute SPL, which makes it a very important graph. So because I was using a 3 dB increment, which the maximum output graph shows, the difference between the lowest and highest sweep in Monolith's case isn't 20 dB but 12 dB (4x3dB) instead.

IMO either way shows the amount of power compression and absolute level clearly as long as one looks at the maximum output graph first/at the same time. My measurements aren't supposed to be viewed as single graphs but as a whole instead. :)
 
Er, thanks, I think :confused:

That's as clear as mud :D

The hard work is appreciated, trust me :smashin:

So do your figures agree with my ears, that the SVS PB10 is better than the Monolith, or not :confused: :rolleyes:
 
Ok, it seems that there is a bit of a confusion. During rounds 1 and 2 I was using a 3 dB increment between the sweeps, not 5 dB like afterwords. So therefore I couldn't use the same way of presenting the power compression. Also one has to ALWAYS look at the basic "maximum output" graph in order to understand the "power compression" and "THD" graphs. Only the maximum output graph shows the absolute SPL, which makes it a very important graph. So because I was using a 3 dB increment, which the maximum output graph shows, the difference between the lowest and highest sweep in Monolith's case isn't 20 dB but 12 dB (4x3dB) instead.

IMO either way shows the amount of power compression and absolute level clearly as long as one looks at the maximum output graph first/at the same time. My measurements aren't supposed to be viewed as single graphs but as a whole instead. :)
Cheers mate,

My point was (although I clearly missed the different sweep levels. Doh!) that the later graphs are a clearer graph to interpret. I realise they lack the actual shape of the maximum output graphs and indeed all of the graphs have to be taken as a whole. The best example is the Spectral Decay graphs. A sub may look 'quick' at 20Hz, but if it isn't actually outputting any energy at 20Hz, it's hardly likely to register on the graph.

BTW, when ARE the new results due?:D

Russell
 
So do your figures agree with my ears, that the SVS PB10 is better than the Monolith, or not :confused: :rolleyes:

Ilkka R said:
And what it comes to measured differences between Monolith and PB10, there are some, but they are not huge. Re max SPL they are pretty even, Monolith has a small 1-2 dB advantage in 30-40 Hz range due its bigger driver and port. It also has a slighly less THD at max level, although a little bit more in the 30-50 Hz range at lower levels. The biggest difference between them is the fact that Monolith doesn't have a so called subsonic-filter below its tuning frequency (20 Hz), which is usually used with vented subwoofers to protect the woofer from over-excursion. This causes a few things:

1. FR profile (slope) is not as steep, because the lack of "extra" 2nd order highpass filter.

2. Group delay stays lower at and below tuning frequency, and system doesn't "ring" as long at system resonance frequency (around 20 Hz).

3. Monolith is more prone to bottom, if high level sub 20 Hz signal is inputted to subwoofer. This was noted while testing and I had to stop the test sweep at two highest test levels to prevent bottoming (below 20 Hz). PB10 has a subsonic-filter, which makes it virtually impossible to bottom.

Does that help answer your question ?
 
Cheers mate,

My point was (although I clearly missed the different sweep levels. Doh!) that the later graphs are a clearer graph to interpret. I realise they lack the actual shape of the maximum output graphs and indeed all of the graphs have to be taken as a whole. The best example is the Spectral Decay graphs. A sub may look 'quick' at 20Hz, but if it isn't actually outputting any energy at 20Hz, it's hardly likely to register on the graph.
Hmm, but why are you now bringing up the spectral decay graphs when we were discussing about the power compression graphs and their differences? I haven't modified the SD graphs. :confused:

Though in any case the spectral decay isn't really an issue with pretty much any of the subs I have tested. A typical room will ring much longer than any subwoofer. Therefore acoustic treatments are the best way (and proper setup of course) to make the system sound more 'quicker'.

BTW, when ARE the new results due?:D

Russell
Soon...very soon. ;)
 
Hmm, but why are you now bringing up the spectral decay graphs when we were discussing about the power compression graphs and their differences? I haven't modified the SD graphs. :confused:
You pointed out that all of the graphs should be read in conjunction. I was pointing out that the SD graphs were also a good example of a graph that by itself, doesn't tell you a lot.

I'm loking forward to those new results though. Any chance they'll be up before I go on Holiday on the 23rd?:lease:

Russell
 
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