Some speaker driver measurements...

Shows what you know about how the series xover actually works. The stopband of the respective drivers effectively short out and transition towards zero. This means that the driver supposedly having HD issues runs by itself while the other is critically damped. Even if you believe that HD could be superimposed to an adjacent driver, the way the filter works will just not do this.

I am not opposed to any kind of xover topology, as long as it is done with a mind for best practices.

"audiophile listening hunting for hidden treasures buried deep in the magic of music "
This is not what xover designer is about. It is about getting the best or optimal results from the design.

"Someone stated a longer while ago the distortions of the midwoofer will re-appear in the tweeter which renders high quality tweeters obsolete!"

Show me the proof, as I would like to see this....
 
Arez said:
One will probably manage to "flatten" the FR wiggles around 1k, by damping agent on the rubber surround. Just as so many of the common rubber surround midwoofers, with untreated surrounds.
The downside is you would need a few sacrificial drivers which is not friendly on the wallet🙂
Click to expand...
These drivers have a penta-cone arrangement which addresses the surround resonance. I've tried to apply a latex ring to the NE149 which appeared to work, but upon listening to the driver, it sounded weird. Luckily I could undo the treatment without hurting the surround. This was on the driver i torture tested.

IMO the reason it didn't work is the cones are very lively in the mids and the higher Qms sort of supports this, which is their strong point. Any attempts to dampen this results in less of that midrange magic. I may try silicone compound instead, which is a little less aggressive in damping nature, but it may be just a tradeoff you have to accept in return for that higher harmonic content from the cone"s mechanical properties.
 
The other thing on the NE180 is how it sounds compared to the FR curve. It should sound as bad as it measures, but it doesn't. Measurments tell you alot about a driver, but they don't always reveal a driver's true nature. The distortion curves support this IMO. The main strengths of the NE180 are how good it sounds in the upper bass and mids. I think the cone profile is part of it as is the material its made from. There are better midbass drivers out there but not that many, especially considering the price.
 
Take a 36 to 38 cm baffle and off set the 149 near a side (tried with the Edge) and it shoulld flatten the 900 hz to 1400 hz circa plateau as well as rule 3 to 4 dB of baffle step at the same time down to 200/300 hz, natural cut off area for a 3 ways with these untis.

In the sim I made the uglier front baffle look worked best. A little like the SB12.3 MTM Zap did with SBACOUSTIC NRX paper drivers.

For the sim in The Edge I offseted the mic at 1 m left and 10 feets to see how I could flat it from around 300 hz to 1400 hz circa... at what could be a listen position. Of course It gives me not the real off axis behavior and wether it is constant directivity.
 
This driver does well on a larger baffle, which I prefer. The lower mids sound much better. It reduces the ripple a little and gives better sensitivity down low.

I found that running 2 of these in MMT or MTM also smooths the lower mids compared to only one driver alone. Its also a more sensitive driver to edge diffraction. A WG probably would help reduce these effects.
 
Well EQ is the way to go if you like another digital conversion step in your signal path, or if listening to digital sources. We analog people prefer passive filters, because they don't add noise. Distortion only becomes an issue with cheap parts.

I won't shy away from a driver with difficult FR (within reason). I wont use one that requires DSP to fix, because if it needs that much hammering into place, it probably has other issues relating to it. For the most part I shy away from LF and mid drivers with very sharp resonances.
 
profiguy said:
I won't shy away from a driver with difficult FR (within reason). I wont use one that requires DSP to fix, because if it needs that much hammering into place, it probably has other issues relating to it. For the most part I shy away from LF and mid drivers with very sharp resonances.
Click to expand...
This is obviously always true 🙂
Yes, there are reasons why the freq resp isn't smooth. So smoother is always better.
Although, sometimes a driver has other perks that can't be found with other alternatives (incl price point).
You just can't see this in a vacuum, there is always a compromise somewhere.

profiguy said:
Well EQ is the way to go if you like another digital conversion step in your signal path, or if listening to digital sources. We analog people prefer passive filters, because they don't add noise.
Click to expand...
You can also make an analog active EQ, if you make sure the noise and distortion are lower than the power amplifier, there is nothing to be worried about.
Also, if the source is digital and the EQ is in the same digital source, there is also no additional noise (or distortion).

profiguy said:
Distortion only becomes an issue with cheap parts.
Click to expand...
There are quite a few VERY expensive drivers, that have pretty nasty audible distortion, if someone doesn't know how to filters correctly.
So it most definitely doesn't only count for cheap parts.

The correlation between price and performance is also not great in general (although people still have that idea it seems).
The ratio between the two is even worse.
 
TNT said:
Whats is a "non-satori" resonance?

//
Click to expand...

When the (ugly/bad) resonances in a paper cone like the Satori-drivers do not hold what they are promising by the name itself!

In other words this "special" paper performs quite ordinary , for me it is just a sales trick with a fancy name!

I remember the first generation of the now called NRX2 cones were extreme unstable in the distortion distribution over frequency ... 2 pcs of SB15 and 2 pcs of SB17 were measured by Hobby Hifi magazine (B&K equipment in non-reflective environment), each one in 4 Ohm and 8 Ohm . None of them had similar distortion spectrum , curves for K2 and K3 goes wildly up and down , chaotic!

So when your stereo speakers were driven by a mono signal , chances are very good that these SB "goodies" have complete different distortion signature!

Lesson to learn : If you measure your speakers make sure both drivers are having a much as possible similar distortion signature for making your stereo experience a nice groovy trip 🙂
 
Sorry but long term in-room resonances do not affect significantly short term resonances , also they are not coupled together! (see SB Satori coax driver data sheet linked above by me)
 
Marveloudio said:
(see SB Satori coax driver data sheet linked above by me)
Click to expand...
yes, and I am saying that this SB datasheet contains a lot of room garbage, therefor the whole freq resp looks totally like junk.

Just compare other SB datasheets to many other 3rd party measurements (incl the ones with Klippel NFS system) and you will know what I mean.

So again, what resonances are you specifically referring to from this graph?
Can you please point at them.
 
You must log in or register to reply here.
Back
Top