Some speaker driver measurements...

[HiFiCompass]

Dear friends,
there are many enthusiasts of loudspeakers building here so I thought this link would be very useful for someone.

http://hificompass.com/en/speakers/measurements

It is needed to register at the website to have a access to the speaker drivers compare feature.
With no registration one can click on driver model name in the table and get to the speaker driver measurements page.
There is the mesurements description above the table. Just click on it.

To moderator - sorry if I place this thread in a wrong place, you can transfer it in the correct place.

Best regards,
HiFiCompass

[HiFiCompass]

The Satori WO24P-8 woofer measurements have been added

http://hificompass.com/en/news/measu...r-measurements

[tktran]

Hello Goran,

Thank you for providing such a useful resource to DIYers.

I have registered, and can now access the comparison feature. This is a novel feature that I haven't seen before.

My interpretation of the data is that the Satori motor system is outstanding. In terms of harmonic distortion, this driver is better than the W22EX below 1000Hz.

It also has the stroke of a modern woofer (9mm geometric x-max), so it could be used as the foundation of a 3 way (good composure with 11.1V input)

I wonder when SB Acoustics will put their metal cones on their Satori range...

[Zvu]

Göran is from Sweden.

This is HiFiCompass aka Audio Gurman from Ukraine.

[TMM]

Thanks for the measurements! Some interesting drivers in there, plus many of the usual suspects to compare with Zaph's data.

[HiFiCompass]

The Accuton C158-8-085 midwoofer measurements have been added:

http://hificompass.com/en/news/measurements/accuton-c158-8-085-midwoofer-measurements

[Jim Holtz]

I'll add a few measurements for the C158 since that is the driver Curt and I used in the Bordeaux.

Jim

[5th element]

I wonder when SB Acoustics will put their metal cones on their Satori range...

That's what I've been waiting for too...

[5th element]

The Accuton C158-8-085 midwoofer measurements have been added:

http://hificompass.com/en/news/measu...r-measurements

Those measurements are not encouraging really and I'm wondering what this drivers role is supposed to be within a system. Midrange distortion is decently low but the third order resonance peak at ~1.3kHz effectively makes this pointless as a dedicated mid. Then you've got its bass performance, which is poor.

As a hard cone midrange I'd much rather use the good old W15CY001. Then again I'd rather use a Dayton RS150 too. Or a SB15/17NAC.

As a smaller format mid/bass or woofer SEAS L16 range are much better.

Heck in general terms the Accuton reminds me of a SEAS L/W16 driver, with their lower frequency breakups, but the SEAS actually give you something for it - best in class bass performance for the chassis size. Not to mention that the SEAS breakups, placing the third order peaks @ around 1.8kHz, make them just about usable when paired with a suitable tweeter.

Yeah I'm roasting the Accuton, but it's expensive and performs poorly vs the competition.

[HiFiCompass]

Those measurements are not encouraging really and I'm wondering what this drivers role is supposed to be within a system. Midrange distortion is decently low but the third order resonance peak at ~1.3kHz effectively makes this pointless as a dedicated mid. Then you've got its bass performance, which is poor.

As a hard cone midrange I'd much rather use the good old W15CY001. Then again I'd rather use a Dayton RS150 too. Or a SB15/17NAC.

As a smaller format mid/bass or woofer SEAS L16 range are much better.

Heck in general terms the Accuton reminds me of a SEAS L/W16 driver, with their lower frequency breakups, but the SEAS actually give you something for it - best in class bass performance for the chassis size. Not to mention that the SEAS breakups, placing the third order peaks @ around 1.8kHz, make them just about usable when paired with a suitable tweeter.

Yeah I'm roasting the Accuton, but it's expensive and performs poorly vs the competition.

Very good and correct post. I can confirm every word and add a bit - almost all Accuton 5"-8" drivers with ferrit magnet motors havn't sense to be used in projects except some lucky models like C90-6-078 (079). I'm saying this from the price point of view too. There are many lower cost drivers having better parameters.

The Accuton drivers with neodymium magnets is a completely different story...

I have worked with many Accuton drivers and know that from my own experience.

[Jim Holtz]

Hi Guys,

Your measurements and analysis do not match Curt's measurements at all. The 3rd order pass band distortion is is down 55-60 db and there isn't a 3rd order peak at 1.3K. Our measurements correlate with the factory (FR and distortion) plus others in the industry that I contacted before buying the driver.

The C158 has the new hybirid motor technology that is very low distortion. If that weren't true, Curt and I would not have used them, period.


Jim

[HiFiCompass]

The 3rd order pass band distortion is is down 55-60 db and there isn't a 3rd order peak at 1.3K. Our measurements correlate with the factory (FR and distortion) plus others in the industry that I contacted before buying the driver.

Sorry, that is not a true...

I've attached printscreen from original datasheet. Look at it.

[dre73]

What is poor about the bass production?
I'm about to start a project with 2x c158 as bass in a 3-way system......:B

[HiFiCompass]

What is poor about the bass production?
I'm about to start a project with 2x c158 as bass in a 3-way system......:B

I wouldn't recommend using them as bass drivers in any case. They have very large harmonic distortions in the bass region. The two drivers will not help too.

[dre73]

Oké........
Why would 2 drivers be a problem?
I would say that the wil do half the work,so less distortion.

Learning every day.....

[HiFiCompass]

Oké........
Why would 2 drivers be a problem?
I would say that the wil do half the work,so less distortion.

Learning every day.....

2 drivers will not be a problem but for that sum you can find much better drivers.

[Jim Holtz]

Sorry, that is not a true...

I've attached printscreen from original datasheet. Look at it.

I try my best to talk out of the top half of my body, not the bottom. Lets take another look;

The measurements Curt took when designing the crossover for the Bordeaux so they are real world, in the listening room results. Here's a repeat;



Curt uses Omni-Mike which uses a little different color scheme but the way I read this is, yes 3rd order distortion is down 55-60 DB in the pass band of a 3-way. Think 500 - 2500 Hz. I would not use this driver for a 2-way and I have no interest in its bass capability. I haven't built a 2-way for myself since 2003, if I remember correctly.



Here is the factory graph;



Just for clarity;



HTH

Jim

[fish fingers]

Oké........
Why would 2 drivers be a problem?
I would say that the wil do half the work,so less distortion.

Learning every day.....

maybe think about a MTM tower design with side firing woofer.

Sent from my SM-G950F using Tapatalk

[HiFiCompass]

I
The measurements Curt took when designing the crossover for the Bordeaux so they are real world, in the listening room results. Here's a repeat;

[ATTACH=CONFIG]28050[/ATTACH]

Curt uses Omni-Mike which uses a little different color scheme but the way I read this is, yes 3rd order distortion is down 55-60 DB in the pass band of a 3-way.

The problem is that for THD measurements were valid using present MLS methods they need to be performed in the direct field area, not a diffused field one. So, the direct/reflected (diffused) signal should be kept as high as possible.
Your measurements, as you say, were performed in real life room conditions. I can suppose, the distance from loudspeaker to a measurement microphone in that real conditions was no less than 2 meters. That means the microphone was in the strong reverberant field as in the majority home conditions reverberant radius lies in 0.5m - 0.9m values. So I can not consider your measurements convincing, sorry.

[Jim Holtz]

The problem is that for THD measurements were valid using present MLS methods they need to be performed in the direct field area, not a diffused field one. So, the direct/reflected (diffused) signal should be kept as high as possible.
Your measurements, as you say, were performed in real life room conditions. I can suppose, the distance from loudspeaker to a measurement microphone in that real conditions was no less than 2 meters. That means the microphone was in the strong reverberant field as in the majority home conditions reverberant radius lies in 0.5m - 0.9m values. So I can not consider your measurements convincing, sorry.

Sorry, you are guessing incorrectly. I'm not going to get into a debate with you about how you "think" Curt does measurements. He is one of the elders in speaker DIY and has been successfully designing speakers for several decades, written several white papers and is one of the most knowledgeable people I know. There are a few on his website you may find of interest. http://speakerdesignworks.com/ However, for clarity, Curt conforms to industry measurement standards.

Send Curt an email and ask how he does measurements. It'll take a while to get an answer but he will respond.

Jim

[5th element]

Jim, I would also say that your drive level isn't high enough either. Mic at a distance + not enough drive level create issues. Firstly the magnitude of the third order distortion will change dependent on the drive level. Getting 2.83VRMS at the terminals of the midrange (as opposed to 2.83VRMS at the loudspeaker binding posts) is loud towards the antisocial end of the spectrum. Then having the drive level too low + too much distance to the microphone creates signal to noise ratio problems. These typically show up at squashed harmonics. Your measurement shows signs of this as the higher order harmonics, in general, bunch up and ride on the 15dB line. We're basically seeing 60-70dB below the fundamental, with both 4th and 5th being fairly together.

With good measurement technique the 4th and 5th will generally go a decent amount further down than 60-70dB (especially at certainly frequencies).

It is also common for people to display the results of HD sweeps in a way that squashes out data too. Troels Gravesen does this by plotting his % distortion on a linear scale, rather than log. He isn't the only one to do this (Accuton do this too...), but it makes all distortion products approaching zero % squash together and look like zero %, or very close to. Where in fact, say the second order, could be riding at 0.4%, the third order 0.1% and the 5th order 0.01%, but they'd all look so close to one another that you can barely see any difference.

When testing drive units the interesting stuff is all between 0.01% and 0.5%, at least with drivers of any quality. This is the area we want magnified as it's the differences, down at these levels, that separate the average of the good drivers from the champions.

[Jim Holtz]

Jim, I would also say that your drive level isn't high enough either. Mic at a distance + not enough drive level create issues. Firstly the magnitude of the third order distortion will change dependent on the drive level. Getting 2.83VRMS at the terminals of the midrange (as opposed to 2.83VRMS at the loudspeaker binding posts) is loud towards the antisocial end of the spectrum. Then having the drive level too low + too much distance to the microphone creates signal to noise ratio problems. These typically show up at squashed harmonics. Your measurement shows signs of this as the higher order harmonics, in general, bunch up and ride on the 15dB line. We're basically seeing 60-70dB below the fundamental, with both 4th and 5th being fairly together.

With good measurement technique the 4th and 5th will generally go a decent amount further down than 60-70dB (especially at certainly frequencies).

It is also common for people to display the results of HD sweeps in a way that squashes out data too. Troels Gravesen does this by plotting his % distortion on a linear scale, rather than log. He isn't the only one to do this (Accuton do this too...), but it makes all distortion products approaching zero % squash together and look like zero %, or very close to. Where in fact, say the second order, could be riding at 0.4%, the third order 0.1% and the 5th order 0.01%, but they'd all look so close to one another that you can barely see any difference.

When testing drive units the interesting stuff is all between 0.01% and 0.5%, at least with drivers of any quality. This is the area we want magnified as it's the differences, down at these levels, that separate the average of the good drivers from the champions.

Hi Matt,

Opps! I just realized I grabbed the distortion measurement of the completed speaker rather than just the C158 in my original post. So, Here ya go!

This is at 2.8 volts



This is at 8.0 volts



There is a slight hump in 3rd order at 8 volts at 1.3K but as you'll notice fades away when the crossover is in place.

I know you've not been a fan of anything Accuton. I've read your posts many times. I wasn't either. Curt has had an Accuton design as his personal reference for several years and they sound wonderful with exceptional clarity and a see into the music detail in the midrange I've just not heard in other drivers. The C158 sound the same so i attribute it to the ceramic cone material they use. I'm also a fan of SB drivers as I know you are. Which make me really interested in their new CAC hybrid ceramic cone drivers.

Anyway, when it comes to measurements etc, I hand off to Curt. That and design speaker crossovers is what he does and he's really good at it.

HTH

Jim

[Zvu]

Here is a simple distortion calculator.

http://www.sengpielaudio.com/calculator-thd.htm

3rd HD peak at 1300Hz is little over 0,5% (that can be seen on Accuton factory measurements) and that's about -46dB.

Here's HiFicompass's measurement of the same driver at 2.83V:




As can be seen, 3rd HD peak is about -42dB which is equal to about 0.8% distortion. His measurements shows slightly higher 3rd order peak (0.8%) which can partly be result of different measuring equipment or measuring technique or driver batch variation or maybe a small part of it is an error - but there is strong correlation with Accuton factory measurements. Error of 0.3% between any system compared to Klippel analysis done few thousands kilometers away is ridiculous. If we look at Curts measurements - there is no correlation (apart the 4KHz 2nd order HD peak) with Accuton factory distortion measurements.

Now, while i'm in the Toole/Olive/Geddes camp who preaches that distortion low as that can not be heard when playing music and C158 is made good where it matters which is why it sounds great in Curts implementation - let's not pretend that it measures better than it really is. That 3rd order peak is real, but Omnimic or measuring conditions do not show the right picture of it.

[fish fingers]

Seeing as this driver has v low THD above 100-150hz, isnt ANY spike made to look more dramatic than it actually is?

The cell C168 is another example.

[Jim Holtz]

Here is a simple distortion calculator.

http://www.sengpielaudio.com/calculator-thd.htm

3rd HD peak at 1300Hz is little over 0,5% (that can be seen on Accuton factory measurements) and that's about -46dB.

Here's HiFicompass's measurement of the same driver at 2.83V:




As can be seen, 3rd HD peak is about -42dB which is equal to about 0.8% distortion. His measurements shows slightly higher 3rd order peak (0.8%) which can partly be result of different measuring equipment or measuring technique or driver batch variation or maybe a small part of it is an error - but there is strong correlation with Accuton factory measurements. Error of 0.3% between any system compared to Klippel analysis done few thousands kilometers away is ridiculous. If we look at Curts measurements - there is no correlation (apart the 4KHz 2nd order HD peak) with Accuton factory distortion measurements.

Now, while i'm in the Toole/Olive/Geddes camp who preaches that distortion low as that can not be heard when playing music and C158 is made good where it matters which is why it sounds great in Curts implementation - let's not pretend that it measures better than it really is. That 3rd order peak is real, but Omnimic or measuring conditions do not show the right picture of it.

Zvu,

You have me confused. The purple line on the Omni Mike system is 3rd order. It is down 50 - 60 db at both 2.8 and 8.0 volts which is .3% to .1% distortion. It is what it is. We had 4 copies that were tested and they were all nearly identical. I do agree with you that distortion that low is insignificant.

Curt's been designing speakers for over 40 years and we've been collaborating on many designs for over 10 years so I'm perplexed when there are posts that insinuate he doesn't know how measure a driver. So, I'm not trying to put lipstick on a pig but if its good, it should be recognized that its good. My thoughts anyway...



Jim

[Scottg]

Curt's been designing speakers for over 40 years and we've been collaborating on many designs for over 10 years so I'm perplexed when there are posts that insinuate he doesn't know how measure a driver. So, I'm not trying to put lipstick on a pig but if its good, it should be recognized that its good. My thoughts anyway...

Jim

There are so many minor differences with measuring distortion that can result in major differences. I still have problems with AudioExpress/Voicecoil test bench method. Zaph even has a big caveat with his measurements.



Regardless of discrepancies in results for the Accuton driver..


I don't think the omnimic system is particularly good for non-linear distortion measurements (regardless of technique). ops:

Arta's STEPS is preferred.

Stepped-sine with REW is also good. (..it's similar to STEPS, but more "fixed" in its test method.)

Both should be used on a dual-channel system with loop-back. (..omnimic necessarily lacks this with its USB sound card/mic.)

REW makes a case for using it without "calibration" - and if doing that you really should be using an excellent 1/2" mic that is professionally calibrated. If it's a decent 1/4" then you can always measure off-axis about 70 degrees to compensate for it's rising response at high freq.s, BUT you likely still have the problem with extreme near-field measurements and microphone distortion.

[Zvu]

+1 ScottG

Zvu, You have me confused. The purple line on the Omni Mike system is 3rd order. It is down 50 - 60 db at both 2.8 and 8.0 volts which is .3% to .1% distortion. It is what it is. We had 4 copies that were tested and they were all nearly identical. I do agree with you that distortion that low is insignificant.

Curt's been designing speakers for over 40 years and we've been collaborating on many designs for over 10 years so I'm perplexed when there are posts that insinuate he doesn't know how measure a driver. So, I'm not trying to put lipstick on a pig but if its good, it should be recognized that its good. My thoughts anyway...

Jim

In measurements done by HiFicompass 3rd HD peak is visible at 2.83V as is at 4V and 5.6V . In Curt's measurements 3rd HD peak starts to become visible at 8.0V and there is no sign of it at 2.8V - that means that S/N ratio is too low and as it gets higher, distortion harmonics begins to separate and that is a good thing because you are starting to measure distortion of a loudspeaker, not the noise.

I'm not doubting in Curt's designer skills - i haven't heard any of his loudspeakers to be able to do that. I was just referring to the part of measurements accuracy. If he thought that everything is visible at 2.8V then he wouldn't try to measure it at 8.0V (when it started to correlate with Accuton factory measurements). That tells me that he is aware of S/N ratio problem and he knows what he's doing.

[5th element]

Hi Matt,

Opps! I just realized I grabbed the distortion measurement of the completed speaker rather than just the C158 in my original post. So, Here ya go!

Well that's certainly helpful

There is a slight hump in 3rd order at 8 volts at 1.3K but as you'll notice fades away when the crossover is in place.

Well indeed, we can see that there is some trending with a slight peak appearing in the right place, but it's not as pronounced. Why, I have no idea, but it almost looks as if it could have been smoothed out. With hard cone drivers the third order peak usually closely resembles the shape of the peak encountered at the drivers resonance. Hificompass' measurements show what you'd expect, as do Accuton's.

The two measurements you have posted are an excellent example of what I was describing about harmonics bunching up and signal to noise ratio though. As you can see, in the first measurement, at 2.8 volts, the 4th and 5th harmonics are only 60dB down. Then at 8 volts they have fallen to ~69dB down. Going from 2.8 to 8 volts increases the signal by ~9dB, so that makes sense. Trouble is the system should be organised so that the signal to noise ratio is high enough to accurately capture the harmonic content at all the drive levels tested. Here it isn't even high enough at 8 volts drive level. I'm with Scott here in that I've never been a fan of the omnimic measurement system for distortion, every measurement I've ever seen with it shows limited resolution and low level detail. This could be attributed to the USB ADC/mic preamp setup, which could quite easily have a pretty high noise floor.

I know you've not been a fan of anything Accuton. I've read your posts many times. I wasn't either. Curt has had an Accuton design as his personal reference for several years and they sound wonderful with exceptional clarity and a see into the music detail in the midrange I've just not heard in other drivers. The C158 sound the same so i attribute it to the ceramic cone material they use. I'm also a fan of SB drivers as I know you are. Which make me really interested in their new CAC hybrid ceramic cone drivers.

Well that's not entirely true, along with Hificompass, I do like their neo/underhung motor drivers. These have always shown pretty good measured performance although cost a fortune. Some of their ferrite drivers are good though, although these are midrange and tweeters and not their woofers. What puzzles me is that Accuton state, pretty boldly, that their drivers have FEA optimised motors, so why don't they have performance that would indicate this? Their ferrite drivers have motors that perform, throughout the midrange, like SEAS older prestige drivers, the ones without any copper/aluminium in the gap. Maybe they aren't using shorting rings, which would help to explain something. Then the other issue with the ferrite drivers is their high bass distortion. This seems to be a problem with all of the ferrite woofers that hificompass has measured. It could be that they need more attention paying to pole/voice coil venting. Their neo drivers definitely have the edge here as they have larger voice coils and with them, significantly larger perforations in the voice coil formers. It's possibly not this though as other drivers, with worse ventilation, don't have this problem.

The CAC drivers caught my eye too. What's nice is that their 4" version contains shorting rings/copper cap, something SB have omitted in their previous 4" drivers. A Satori with a hard cone would be great though!

[HiFiCompass]

I would like to add that up to some sound pressure levels there is no strong correlation between harmonic distortion and perceived sound quality. So it is not surprising that C158-8-085 sounds quite good in a system. The main task of my measurements is to analyze and show how good from engineering point of view loudspeaker drivers are made. Conclusions are to be made by one himself.
In the 95-98% of all my measurements I do them as minimum as for two drivers and publish the better measurements for to not spoil a driver reputation due an occasional defect. It is often a case that I take one from 4-6 different driver measurements for the same reasons.
The hard cone drivers as usually have better consistency than soft cone ones.
On the way are many much more interesting drivers which will cause much more questions and puzzles.
Stay tuned

[Jim Holtz]

Well, that stimulated a conversation. 8O Lots of different viewpoints regarding methods and preferences for measuring equipment it seems. LOL, I should know better than to get involved in type of discussions. Curt does the "brainy" stuff and I'm the idea guy and builder.

Jim

[Curt C]

I would like to add that up to some sound pressure levels there is no strong correlation between harmonic distortion and perceived sound quality. So it is not surprising that C158-8-085 sounds quite good in a system. The main task of my measurements is to analyze and show how good from engineering point of view loudspeaker drivers are made. Conclusions are to be made by one himself.

I agree with HiFi compass in this statement. Harmonic distortion plots in and of themselves can be quite revealing, and are quite easy to measure in-room, but are far from painting an exhaustive distortion portrait of a driver. Another revealing measurement would be measuring the intermodulation components using various multi-tone stimuli. Unfortunately I lack the software to perform these measurements, and most OEM’s don’t bother to publish them assuming they measure them. One of the reasons I so favor the Accuton line is their ability to reproduce audible microdetail which can normally only be heard in the ‘black spaces in between the notes’ for want of a better term. Revelators have a wonderful sound and measure very well, but sound quite different from the Seas Excel which also have a wonderful sound and measure very well. I find the Accuton’s in general strike some middle ground between the two and in some aspects exhibits the best of both worlds. Your tastes may differ.

As far as my HD measurement conditions are concerned. I generally do not perform nearfield tests, nor test them on an IEC baffle. I instead test them individually at 1 meter on their intended baffle. This may not provide the same results as another measurement method, but I find that for myself they still provide useful information. I use 2.8v as this will result in something around 90 dB with most drivers. Since 90 dB is generally about the level I find comfortable for listening to most music, it is of some value to me to measure the distortion at that level. I also measure at 8 volts as that level will start to stress many drivers and make some of their flaws more obvious. I measure system HD plots the same way and at the same distance and levels.

I would suggest caution in basing a driver choice on just a few tests. With my engineering background, I used to pour over the various plots for different drivers thinking I could find the best driver based on measurements alone. -Many years later I realize how simplistic this viewpoint was, and now consider them just one tool in my arsenal. Remember your ears are the most sensitive measurement equipment you own, and should be part of your measurement regimen in order to find the optimum components for a specific design.

C

[Dave Bullet]

I would suggest caution in basing a driver choice on just a few tests. With my engineering background, I used to pour over the various plots for different drivers thinking I could find the best driver based on measurements alone. -Many years later I realize how simplistic this viewpoint was, and now consider them just one tool in my arsenal. Remember your ears are the most sensitive measurement equipment you own, and should be part of your measurement regimen in order to find the optimum components for a specific design.

C

If components means crossover and drivers, I couldn't agree more with this statement. I decided to swap between Seas 27TDFC/G and 27TBFC/G tweeters (yes you read that correctly - fabric vs. metal domes - both with Seas hexagrid covers) and excluding minor 0.5dB sensitivity gain of the 27TBFC/G, when level matched, on certain tracks the B was forward, especially on compressed 80s music and some male vocals. Whereas the D version was balanced and allowed me to hear the upper treble. PS: identical crossover (tweeter only playing).

I confirmed the above with another pair of ears :-) (PS: they were returned to the owner).

For the life of me, with my limited experience and measurement tools and skills - I could not see the difference via measurements to have picked this up.

Only my ears could.

[HiFiCompass]

If components means crossover and drivers, I couldn't agree more with this statement. I decided to swap between Seas 27TDFC/G and 27TBFC/G tweeters (yes you read that correctly - fabric vs. metal domes - both with Seas hexagrid covers) and excluding minor 0.5dB sensitivity gain of the 27TBFC/G, when level matched, on certain tracks the B was forward, especially on compressed 80s music and some male vocals. Whereas the D version was balanced and allowed me to hear the upper treble. PS: identical crossover (tweeter only playing).

I confirmed the above with another pair of ears :-) (PS: they were returned to the owner).

For the life of me, with my limited experience and measurement tools and skills - I could not see the difference via measurements to have picked this up.

Only my ears could.

Dave, I have the measurements of both drivers you told about. I will publish them in one-two weeks. I don't remember if there is a big difference between them.

[Dave Bullet]

Dave, I have the measurements of both drivers you told about. I will publish them in one-two weeks. I don't remember if there is a big difference between them.

Thanks - I'd be interested to see the HD distortion plots.

[bvbellomo]

I wanted to chime in as a big fan of the C173-6-096E. Nonlinear distortion measures well, within my limited ability to measure, but frequency/response is nowhere near ruler flat. Nothing about this driver I've measured measures well enough to justify anywhere near its price point. Yet it is responsible for great reviews on the Avalon Isis and similar to what Jon used in the Ardent. The Accuton neodymiums are fantasic, and not just from low distortion.

Linkwitz said that "There is a level of non-linear distortion that is 'good enough' relative to other flaws in the loudspeaker. Further reduction of this distortion brings no audible improvement. ".

There is something I really like about this driver I can't measure. I think Curt C hits it pretty well as 'black spaces in between the notes'. There is also extremely clean separation between 2 different sounds happening at the same time in the driver's bandwidth. I am not saying this can't be measured - it probably shows up in the CSD or Thiele Small parameters (Mechanical Q?) somewhere, but I am not good enough at this yet to know what.

[5th element]

The C173-6-096E is one of Accuton's excellent drivers though. I'd recommend it to anyone half decent with xovers, shame about the price though.

[HiFiCompass]

The measurements and review of BlieSMa T34A-4 tweeter have been added

http://hificompass.com/en/content/bliesma-t34a-4-34mm-alumag-dome-tweeter

[Jonasz]

The measurements and review of BlieSMa T34A-4 tweeter have been added

http://hificompass.com/en/content/bl...g-dome-tweeter

Wow, that’s an interesting tweeter! 1.3 mm one way xmax and 1.3kHz cut off makes for some really interesting designs. Very unique and good looking too imho... :-)

[HiFiCompass]

I'm agree but linear excursion is no less than 1.5 mm one way...

Air gap height is 4.5 mm
Voice coil height is 1.4 mm

[Jonasz]

I'm agree but linear excursion is no less than 1.5 mm one way...

Air gap height is 4.5 mm
Voice coil height is 1.4 mm

Ooops, I dunno why I wrote 1.3 mm...

[fish fingers]

price brings it in range of the SB Be domes, but the many unique features and low crossover point will be selling points for sure

Sent from my SM-G950F using Tapatalk

[5th element]

Finally someone who makes a tweeter that doesn't have one of those stupid big surrounds. I never really understood the point in those besides 'fashion'.

The second order distortion of that tweeter surprises me though, not that it's high, it's just higher than I'd expect. Then there's the shape of it. Rising below 6kHz, the frequency of the start of the rise remaining constant with the increase in drive level. Then it starts to slowly fall around 2kHz before it reaches a minima somewhere below 1kHz. It makes me wonder what mechanic is responsible for that 2nd order 'hump'. It's obviously not the motor or suspension parts losing linearity with increased excursion, which is usually the case. If they managed to remove the hump, so that the 105dB 2nd order was basically a flat line at -47dB down to around 1kHz...it'd be insane.

The companies website appears to be under construction for the moment, but I like the direction that this tweeter indicates their other drivers could take...I wonder what else they've got in the pipeline!

[Zvu]

Imagine this fellow in apropriate 8"/10" waveguide.

[cochinada]

It really looks awesome :T

I would be very interested to see a comparison between this and any Transducer Lab tweeter. Well in particular the N26MGR-G which if I remember correctly in my amateurish measures had less than 10db in the off-axis response up to 60º and has very low distortion as it is well known.

[Scottg]

Finally someone who makes a tweeter that doesn't have one of those stupid big surrounds. I never really understood the point in those besides 'fashion'.

Most of those newer tweeters with that "fetish" are effectively radiators - and though they increase operating surface area their suspension typically results in even lower excursion potential. (..in fact, you can pretty much tell if the driver is like this based on its linear excursion.) Most ring radiators are just plain over-damped IMO (..though Scanspeak's Revelator and Illuminator have variable profiles - "shaving" mass (from the rear) that results in something much less damped in certain areas - with resulting greater clarity.)

I like the design of Transducer Labs tweeters: a "polar-opposite" to that sort of design. Light (real) surround with good linear excursion and a dome so rigid it didn't need a lot of edge-damping.