An Objective Comparison of 3in - 4in Class Full Range Drivers

[planet10]

is lack of downward dynamic range a type of hysteresis where some drivers for whatever reasons never produce the soft sounds in proportion in the first place and not an artifact of ringing?

That might be one way to describe it. DDR has nothing to do with resonance.

DDR is the ability to reproduce the information 30-50 dB down in the presence of the main signal. How do you measure the FR 30dB down? If it is flatter than the main signal does that make it better. If it smooshes all that information into an unrecognizable ooze it certainly is at a disadvantage.

dave

 

[planet10]

When talking about drivers and speaker design, it helps to create a structure that everyone fully understands. So, when things like "DDR" are bandied about, it is not helpful to the discussion at all, because nobody understands what "DDR" is. What is high "DDR?" Why do I want it? How do I measure it? If I cannot measure it, then as a speaker manufacturer, how do I know when I have it? Oh, you say I must listen to the driver? Then, how do I communicate to the speaker designers about why I designed the driver this way?

DDR as a term has been around for at least 20 years. People have used other terms to try to describe the same thing for a lot longer than that.

If car manufacturers had the same kind of attitude you express then a 1950 Buick would be state of the art.

dave

 

[planet10]

Planet10,
Will remind you often point out how urgent in FAST system to use 1. ordens XO to keep phase flat as possible. Now you praise a driver with buildin brickwall steep kind of bandpass that will change timing on all notes played in the two steep slopes where phase will turn as crazy and instrument firering notes these areas will have timing heavily distorted, group delay won't be pretty.

Your point? I did not praise CHN, it is a cheap driver with limited performance. I just said that it was considerably better than the VIFA, an eveb cheaper driver engineered for use in TVs. And you use XRK's measure as a basis for your conclusion... a measure that, taken near-field, in not valid for anything... all the 12.x cm measures can be thrown out. Time to start over again.

dave

 

[planet10]

This perception might be alleviated if 'sample' or 'test' drivers were not given freely to the proponents in question.

I may be perceived as in that category. I pay for all my drivers. And i try out lots of them. I mostly talk about the ones that make the cut, and those are the ones that stay around the house and are available for comparison.

CHN70 just happens to be one ofthe driver under evaluationand currently handy. All the other handy ones are more expensive -- and better.

dave

 

[xrk971]

All the 12.7cm measurements can be thrown out because they don't happen to match the published response for the CHN70, but for the other 6 drivers they match?

 

[planet10]

All measurements are relative to the environment in which the are made, but if measurements are not capable of being extended, analogously, to different environments (e.g. from an anechoic chamber to someone's living room), then what's the point of the measurements?

Exactly.

They are useful tools to the designer, but trying to extend them beyond their evelope is fraught with problems.

dave

 

[Philosophil]

I may be perceived as in that category. I pay for all my drivers. And i try out lots of them. I mostly talk about the ones that make the cut, and those are the ones that stay around the house and are available for comparison.
dave

This is an important point to make explicit, as a disclosure.

 

[planet10]

Ok, now we are clinging onto the need for identical anechoic chambers and $2k mics and $10k LMS setups before any non "meaningless" comparison can be made?

No -- i am saying that trying to directly compare, or to fault them based on the other, is not realistic.

Each has its own uses.

But, that all your measures are done nearfield and not farfield does invalidate them.

dave

 

[planet10]

All the 12.7cm measurements can be thrown out because they don't happen to match the published response for the CHN70, but for the other 6 drivers they match?

I don't care if they match. They are not farfield so very suspect. Particularily in the HF. Time to throw them out and start again.

dave

 

[ra7]

XRK, there is no way to convince Dave, neither is there a need, as you noted. Let's keep this thread about objective measurements. I would suggest you report the posts that are not to the topic (including some of mine 🙂) and have them removed by a moderator other than Dave.

 

[planet10]

This is an important point to make explicit, as a disclosure.

Not the 1st time i have done so.

Literally 100s of FR drivers have passed thru here.

dave

 

[planet10]

This is fun.

dave

 

[phivates]

This is a forum. Dave speaks for listeners not meter readers when lines are drawn but we're not in a war here, right?

 

[BYRTT]

Your point? I did not praise CHN, it is a cheap driver with limited performance. I just said that it was considerably better than the VIFA, an eveb cheaper driver engineered for use in TVs. And you use XRK's measure as a basis for your conclusion... a measure that, taken near-field, in not valid for anything... all the 12.x cm measures can be thrown out. Time to start over again.

dave

That plot was not the 12,7 cm one but taken as below described.

Per members' requests for: 5dB increments, 1 meter distance, 2.83v drive level, 5 ms gating to remove low frequency room effects (don't look below 200Hz), 1/48th octave smoothing, etc. Distance measured with a ruler from driver bezel to mic at driver centerline axis. The manufacturer's rated SPL sensitivity matches pretty closely what I measure, an indication that my calibration is OK on absolute SPL scale. I am new at using gating in REW, I set to 5ms, which means 100Hz resolution, and nothing below 200Hz is any good. Let me know if this is an incorrect setting to use for displaying the data to remove room effects.

TC9FD vs CHN-70:

 

[norman bates]

True.

Good CSD probably helps.

My 12 x 4" focused array had the "transparent" sound.
That would be low distortion also compared to a single 4" (w4-1337sdf).

I miss that thing.

My dual 4" bamboo was more transparent than thiel model 4's.
That I attribute to not going through any caps or huge 6db crossover thiel is known for.

 

[planet10]

That plot was not the 12,7 cm one but taken as below described.

True, but that one is so wonky, if i were X i'd be embassed to show it, except for the purpose of getting help figuring out what i was doing screwy.

dave

 

[planet10]

Good CSD probably helps.

A good CSD is very useful in helping dig out ring-down behaviour, reflections etc. It really needs to have a time scale in periods, the more oft seen msec time scale ones are VERY hard to interpret.

And 30-40 dB depth would be much more useful (25 dB seems common).

And i wish someone would come up with an interactive 3D graph that you could at least rotate.

dave

 

[infinia]

This is a forum. Dave speaks for listeners not meter readers when lines are drawn but we're not in a war here, right?

interesting and nobody claims maybe one driver is broken.

no driver has majical properties, its just basic psychics folks, don't panic LOL

seems somebody has got a dog in this match

 

[BYRTT]

True, but that one is so wonky, if i were X i'd be embassed to show it, except for the purpose of getting help figuring out what i was doing screwy.

dave

Please Planet10 why should he be embarrassed we in diy free forum not commercial sector all tests shown same.

Can't see so much failure is at play, don't think plot will change much and based this find it strange your experienced ears prefer the brickwall slopes crazy phase turn and timing distortion, but let it be we at diy free forum.

 

[tuxedocivic]

Those 1m graphs are throw aways. I think xrk knows that. He needs to adjust the gate. No big deal. But conclusions shouldn't be drawn from them right now. If xrk saved the file, it's easy to change to 3ms.