Erin's Audio Corner gets a Klippel NFS!

[Rockfella]

Congrats OP

 

[hardisj]

HEY, just caught your excellent YT interview with Gene of Audioholics, quick subwoofer question for you: what do you recommend if I needed a solid LFE home theater sub connected to a pre/pro that has its own bass management (don't need the sub to have sophisticated settings/DSP/app)? Would it be the $800 Monoprice THX 12-inch sub?

I think so. That's kind of been my opinion of the two. If you don't have a good room EQ (like Dirac) then the SVS is helpful with its 3 bands of P-EQ. But if you don't need that then the Monolith has the edge on performance output below around 50Hz (if I recall correctly).

 

[hardisj]

So how much of this well controlled directivity is as a result of the physical design and how much from the DSP? If DSP, then we can expect to see this level of performance coming down to consumer friendly levels in the near future (like the Buchardt A500).

As mentioned, in the case of the DD8C the hardware is the reason for the cardioid design.

That said, there are ways to use DSP to "beam steer" the response and shape the directivity pattern. A concept used in radar systems to track planes, missiles, etc.

A fine, though expensive, example of this is what B&O have done with the Beolab 90.
https://bangolufsenassistentgohe.bl...beolab_90_technical_sound_guide_version_9.pdf

BTW, if anyone happens to own a pair of these and wants to loan them to me for testing....

 

[hex168]

Well, the front half of the speaker wouldn’t be terribly hard to replicate. The difficult part is the cardiod and rear drivers, where in the software you tell it the distance from the front wall and it then adjusts roll-off, as well as even timing I believe in order to have optimal bass.

As for Buchardt, their new speakers have awesome tech. However, they still use a 0.75” tweeter to my knowledge, which (to my knowledge) hinders their crossover region even with their large waveguide and the thus have a dip in the sound power, crossing over a 6“ driver at 2800Hz will do that. Here is the A700 measurements from their site:

The owner has stated this was chosen I order to have a wider soundstage in the upper treble. That is a valid reason to do this, but I wonder which would sound better.

Another advantage of the 0.75" tweeter is it makes the waveguide design easier. My understanding is that the narrower throat moves some wavelength-related problems up out of the audible range.

 

[MZKM]

Another advantage of the 0.75" tweeter is it makes the waveguide design easier. My understanding is that the narrower throat moves some wavelength-related problems up out of the audible range.

Maybe, stuff like that and the soundwaves coming out having an acoustical impedance mismatch is over my head.

 

[jhaider]

Please have a look at the text below the graph, it says "Norm. to 0°".

I believe it means normalized to 0°.

Oops. I expect you're right. Ich kann auch nicht etwas eingerostete Deutschkenntnisse verübeln! (I'm sure I got the ending to something wrong there...)

Thanks for pointing that out.

 

[hardisj]

Sometimes life is funny...

I used the (still yet to be finalized/released) beta copy of the new Klippel software to generate the contour plots, with Klippel's help. The new Klippel software is so much better than the previous version wrt graphing. For example, I can make all these plots directly within their new Visualization module without having to port the data to Matlab and run a script to make it look good. So, that's what I'm going to do. I'm just going to use their baked-in graphics and save myself the hassle of generating the data myself.

This is non-normalized:

And then this is normalized to the on-axis response:

 

[hardisj]

more fun stuff and teasers...


normalized vs not

 

[MZKM]

Sometimes life is funny...

I used the (still yet to be finalized/released) beta copy of the new Klippel software to generate the contour plots, with Klippel's help. The new Klippel software is so much better than the previous version wrt graphing. For example, I can make all these plots directly within their new Visualization module without having to port the data to Matlab and run a script to make it look good. So, that's what I'm going to do. I'm just going to use their baked-in graphics and save myself the hassle of generating the data myself.

This is non-normalized:

View attachment 115668



And then this is normalized to the on-axis response:

View attachment 115669

Hmm, what is happening around 2500Hz on-axis?

Regardless, love these graphics! These look so nice.

 

[617]

Hmm, what is happening around 2500Hz on-axis?

Regardless, love these graphics! These look so nice.

The color scale on these is quite compressed - looks to be a dip of around 2db.

 

[hardisj]

I can't divulge too much more.

 

[ctrl]

The new Klippel software is so much better than the previous version wrt graphing.

Finally, now also Klippel supports the probably most widespread representation in spectrograms (stepped colors, 3dB steps) - that's great news.

 

[Koeitje]

I can't divulge too much more.

D&D 8C?

 

[Frank Dernie]

So how much of this well controlled directivity is as a result of the physical design and how much from the DSP? If DSP, then we can expect to see this level of performance coming down to consumer friendly levels in the near future (like the Buchardt A500).

The cardioid characteristic is made feasible by side vents of the mid unit in the D&D and side firing units on the Kii. Speakers without that radiation potential won't be able to do what they have done.
I believe DSP is fine tuning if the speaker drive units are good.

 

[Frank Dernie]

That said, there are ways to use DSP to "beam steer" the response and shape the directivity pattern. A concept used in radar systems to track planes, missiles, etc.

But doesn't this always require multiple radiators for the DSP to work with and exploit interaction? The D&D is a simple and elegant solution, Kii more complex and B&O much more so and more flexible, but none of them beam steer a single radiator, so doing this sort of thing by modifying a 2-way is not going to happen (I think).

 

[MrPeabody]

Well, the front half of the speaker wouldn’t be terribly hard to replicate. The difficult part is the cardiod and rear drivers, where in the software you tell it the distance from the front wall and it then adjusts roll-off, as well as even timing I believe in order to have optimal bass.

As for Buchardt, their new speakers have awesome tech. However, they still use a 0.75” tweeter to my knowledge, which (to my knowledge) hinders their crossover region even with their large waveguide and the thus have a dip in the sound power, crossing over a 6“ driver at 2800Hz will do that. Here is the A700 measurements from their site:

The owner has stated this was chosen I order to have a wider soundstage in the upper treble. That is a valid reason to do this, but I wonder which would sound better.

It may be that the small tweeter contributes to the dip in power at the crossover point, and without doubt there are tradeoffs regardless, as there are with anything.

However, the thing I want to point out is that the dip you see in sound power is attributable to something more fundamental. Whenever the crossover is phase coherent for the two drivers (LR2, LR4) such that the both drivers are at -6.02 dB at the frequency where they are equal in sound pressure, there will be a -3 dB dip in sound power. The reason is that each driver is generating only 1/4 as much power at this frequency compared to the nominal power for the individual driver, and since power sums in the simplest possible manner (due to the law of conservation of energy), it follows that the combined power (both drivers) is half the nominal power. Yet, there is no corresponding dip in sound pressure directly to the front of the speaker. This may be attributed, evidently, to an improvement in the acoustic impedance match for each driver individually, by virtue of the pressure increase resulting from the other driver. The improvement in the acoustic impedance match yields an improvement in efficiency, and correspondingly to an improvement in sensitivity, but only so long as sensitivity is interpreted from the standpoint of sound pressure measured directly in front of the speaker (and possibly measured close to the speaker).

 

[hardisj]

But doesn't this always require multiple radiators for the DSP to work with and exploit interaction?

Yes. I was just replying to the fact that there are some options out there that employ DSP for this purpose.

 

[Rockdog]

As a new member, lay person with some technical aptitude and interest, and a longtime audiophile who has consumed about 40 straight years of "lifted veils" and "better drive and pace" type fluffery BS when trying to best discern how to spend hard earned money on products that offer honest value, thank you!

Amir has put real science on the map in truly disruptive way in this industry (as the naysayers prove) and Erin's acquisition of this machine will add to many more reality based reviews being available. So cool!

Many thanks to Amir for a much needed and growing resource, and how beneficial and classy to see him accept and cooperate with Erin as an additional reviewing contributer. Good stuff in a world full of egos and self interests these days.

This is a fascinating thread, for one reason in that in demonstrates how all over the map various reviews, reviwers, publicarions, and methods can be, and certainly have been for most of audio history. Imagine just 10 years ago there were no meaningful standardized tests, particularly for speakers, but electronics too. I've read Toole and appreciate what Harmon has done to revolutionize the industry in this direction and how Amir and Erin are taking this further into the sunshine for all of us. Its a breath of "standardized" fresh air to see the importance of pursuing consistency here.

Kudos gentlemen! Look forward to much more of your work, and one heck of a site, Amir.

PS because of this site I have a pair of 228be's in route. So stoked! We shall see if you guys have steered me wrong!

 

[McFly]

As a new member,

PS because of this site I have a pair of 228be's in route. So stoked! We shall see if you guys have steered me wrong!

You have made a wise choice. Enjoy your spoils.

Wish we could get the blasted things down here. Heck I'd be happy with the F208s.

I cant wait to see more reviews out of Erin. What a legend, you've come a long way from wearing pink wigs and blasting classical in civics lol. FEED ME MORE INFORMATION

 

[hardisj]

Writing the DD8C review now. Teaser pic. Reference point. Even though it may look like the mic is more toward the midrange, this is indeed halfway between the tweeter and midrange

(no, the mic is not physically touching the speaker but it's darn close )