[redskinsfan]

Rick,

Now that you've had the opportunity to use both in several of your designs, do you believe that the ScanSpeak 7'' Illuminator woofers sound sufficiently ''better'' than the 7'' Revelators to justify the approximately $100 more that you pay for them? 

[kip_]

Would be interested to know this as well, especially since the guy from Zaph thinks the illuminators are inferior

[satfrat]

I was hoping someone would ask for more info about the Scan Speaker Illuminator as I hadn't heard anything about this driver myself but just assumed it was the next step up in the evolution of excellent sounding Scan Speak drivers. I love the design work done on both sides of the Illuminator cone, never did take to the Revelator's slit design myself.

Cheers,
Robin

[kip_]

satfrat - here are some FR and distortion curves from both. P.S. Anyone have a guide on how to read a distortion curve?

http://www.zaphaudio.com/6.5test/

[satfrat]

satfrat - here are some FR and distortion curves from both. P.S. Anyone have a guide on how to read a distortion curve?

http://www.zaphaudio.com/6.5test/

 

That's funny, I'm not much of a chart reader myself. Other than hearing for myself, I'd rather hear what Rick's opinion is as I'm sure he's done driver evaluations himself by ear and not chart.

Cheers,
Robin

[Kevin Haskins]

Hope Rick doesn't mind me jumping in here but I love looking at charts.     

First off, take all distortion measurements made outside of a chamber with a grain of salt.   Taking good measurements that are representative of a production run is not as trivial as some people think.    There are variations in production runs of drivers so it is more useful to look at a sampling rather than a single unit.

Second... you have to consider the application for a driver.   The Zaph measurements are without any crossover and outside of the final acoustic environment.   Once you put it in a box with a port and add a crossover, the distortion measurements look different.    For someone used to designing stuff, you can look at Zaphs measurements and know that your distortion will be another 30dB down at a given point so that rising distortion in the driver may be meaningless for the final build.

Third....  types of distortion and where it is at is as important as a raw THD number.   We are more sensitive to distortion in the midrange than we are at low frequencies.   You can have fairly high low frequency distortion and not even know it.    Also... high-odd order distortion products are more objectionable than low even-order products.    It is very much the case that you can have a lower THD part that sounds much worse than a higher THD part because THD alone doesn't take into account the type of distortion.   

Both of the SS woofers look pretty good to me.   The older one looks easier to work with but that cool motor design might be worth the extra $100   

Just my 0.02

[Rick Craig]

Rick,

Now that you've had the opportunity to use both in several of your designs, do you believe that the ScanSpeak 7'' Illuminator woofers sound sufficiently ''better'' than the 7'' Revelators to justify the approximately $100 more that you pay for them? 

It really depends on the application. The Revelator is more extended on the top end and has a little better off-axis response so it's better suited to tweeters that need a higher crossover point. In the case of the Mejor I had more leeway (the RAAL can cross lower and the DEQX provides a steep slope) so I went with the Illuminator. If you have a tweeter that can cross low and tend to play things loud then the extra cost of the Illuminator may be worth it. If not, then the Revelator is still a great woofer and of course less expensive.

I've not compared them side-by-side but the two best designs I've heard with a 7" midbass (my Galena design -obviously biased   and Salk HT3) fall short of the Mejor. Now part of that could be due to the RAAL and DEQX but the midrange clarity,detail, and smoothness are just outstanding. I'm having another AC member over tomorrow to listen and perhaps he can comment as well.

[richidoo]

 

[Val]

Now imagine a Mucho Mejor with the Raal 70-20!

[Rick Craig]

Would be interested to know this as well, especially since the guy from Zaph thinks the illuminators are inferior

His conclusion is based on a few tests and no listening.

[Rick Craig]

Hope Rick doesn't mind me jumping in here but I love looking at charts.     

First off, take all distortion measurements made outside of a chamber with a grain of salt.   Taking good measurements that are representative of a production run is not as trivial as some people think.    There are variations in production runs of drivers so it is more useful to look at a sampling rather than a single unit.

Second... you have to consider the application for a driver.   The Zaph measurements are without any crossover and outside of the final acoustic environment.   Once you put it in a box with a port and add a crossover, the distortion measurements look different.    For someone used to designing stuff, you can look at Zaphs measurements and know that your distortion will be another 30dB down at a given point so that rising distortion in the driver may be meaningless for the final build.

Third....  types of distortion and where it is at is as important as a raw THD number.   We are more sensitive to distortion in the midrange than we are at low frequencies.   You can have fairly high low frequency distortion and not even know it.    Also... high-odd order distortion products are more objectionable than low even-order products.    It is very much the case that you can have a lower THD part that sounds much worse than a higher THD part because THD alone doesn't take into account the type of distortion.   

Both of the SS woofers look pretty good to me.   The older one looks easier to work with but that cool motor design might be worth the extra $100   

Just my 0.02

I don't mind at all your input when you agree with me. 

[Rick Craig]

satfrat - here are some FR and distortion curves from both. P.S. Anyone have a guide on how to read a distortion curve?

http://www.zaphaudio.com/6.5test/

Kevin made some good points and I'll add a few things. Distortion is only one performance aspect of a driver. Zaph has made it his litmus test; however, a measurement is only worthwhile if it correlates with what we hear. For instance, he pretty much trashes ribbons for being inferior on distortion tests yet we and others like Salk Sound have had great success with them. So one must conclude one (or more) of the following:

1) the tests don't show what we find to be accurate sound

2) if you like ribbons you enjoy distortion

3) the tests need to be made with a crossover in place to better reflect a normal listening situation

4) other performance aspects of a driver are more important than distortion

[cadobhuk]

Is it really the distortion that makes ribbons sound better than domes to many people? Does it have nothing to do with a lower moving mass, faster attack and decay, higher extension that I thought would be the qualities of ribbons?

[Rick Craig]

Is it really the distortion that makes ribbons sound better than domes to many people? Does it have nothing to do with a lower moving mass, faster attack and decay, higher extension that I thought would be the qualities of ribbons?

I mentioned that tongue-in-cheek because Zaph made that conclusion. If that were true then why do I (and many others who enjoy ribbons) also like drivers that measure low in distortion? The things you list I'm sure contribute to what we like as well.

[satfrat]

satfrat - here are some FR and distortion curves from both. P.S. Anyone have a guide on how to read a distortion curve?

http://www.zaphaudio.com/6.5test/

Kevin made some good points and I'll add a few things. Distortion is only one performance aspect of a driver. Zaph has made it his litmus test; however, a measurement is only worthwhile if it correlates with what we hear. For instance, he pretty much trashes ribbons for being inferior on distortion tests yet we and others like Salk Sound have had great success with them. So one must conclude one (or more) of the following:

1) the tests don't show what we find to be accurate sound

2) if you like ribbons you enjoy distortion

3) the tests need to be made with a crossover in place to better reflect a normal listening situation

4) other performance aspects of a driver are more important than distortion

I would think # 3 is the only tongue in cheek choice here. You've made it pretty clear that it's the implementation of ribbons that determine their performance such as crossover and driver matchups, not chart readings. So that would justify #1, #2, and #4 in my mind.

I'm a dome man myself, chrome-dome to be presise. Know what I mean Rick?

Cheers,
Robin

[Kevin Haskins]

Hope Rick doesn't mind me jumping in here but I love looking at charts.     

First off, take all distortion measurements made outside of a chamber with a grain of salt.   Taking good measurements that are representative of a production run is not as trivial as some people think.    There are variations in production runs of drivers so it is more useful to look at a sampling rather than a single unit.

Second... you have to consider the application for a driver.   The Zaph measurements are without any crossover and outside of the final acoustic environment.   Once you put it in a box with a port and add a crossover, the distortion measurements look different.    For someone used to designing stuff, you can look at Zaphs measurements and know that your distortion will be another 30dB down at a given point so that rising distortion in the driver may be meaningless for the final build.

Third....  types of distortion and where it is at is as important as a raw THD number.   We are more sensitive to distortion in the midrange than we are at low frequencies.   You can have fairly high low frequency distortion and not even know it.    Also... high-odd order distortion products are more objectionable than low even-order products.    It is very much the case that you can have a lower THD part that sounds much worse than a higher THD part because THD alone doesn't take into account the type of distortion.   

Both of the SS woofers look pretty good to me.   The older one looks easier to work with but that cool motor design might be worth the extra $100   

Just my 0.02

I don't mind at all your input when you agree with me. 

Ok... I'll keep to myself when I don't. 

And I think you hit the nail on the head.   If you look at one measurement, and make it your litmus test, then you come to conclusions based upon one test/measurement.    If it was that simple we would all have it figured out long ago and everyone would agree on what works best based upon that one simple measurement.

[milosz]

I'm going to come late to this thread and post a few thoughts that might be helpful to someone looking at 7 inch drivers and trying to decide what to buy....

One thing to consider about the Illuminator is it has a larger linear excursion, so in theory it could move more air. This means a number of different things, including the possibility of louder bass; also don't forget if you are using EQ at the low end this usually means some boost at the lowest octaves, and so you might benefit from increased excursion.  Just one of many factors to consider.  This excursion difference is one thing you can plug into simulations and so on, so it's a little more 'calculable' than the more subjective aspects of a driver like midrange resolution , etc.

As regards Zaph's measurements, their value comes not from an absolute numerical characterization of each driver in and of itself, but from the ability to compare the drivers he tests to the other drivers he tests. This doesn't give you a definitive picture of the driver's performance, but it gives you important information when comparing these various drivers. Gives you a PART of the picture. Which is a good thing to have when working up a DIY design.

For Zaph's tests of these 7 inch drivers, I like to look not at the absolute numbers of the distortion above 200~250 Hz, but the SHAPE of the distortion results- how quickly does it fall away as frequency rises, what is the relationship between F3 and F2 as frequency changes, and so on.  This gives some information.  What this all means to the overall sound will not be apparent to you until you work with some of these drivers or listen to projects other folks have made using these drivers. Nothing informs like direct experience.  And of course looking at the breakup peak (if any) and it's impact on distortion will influence how you build a passive xover.

SPEAKING OF TESTS I like the kind of tests that Siegfried Linkwitz puts drivers through, which include some dynamic tests (tone bursts) and so on.  Voice Coil magazine also puts drivers through a gauntlet of tests, worth looking at to see if the driver you like has been tested at Voice Coil.  They especially have a lot of "woofer centric" type tests relating to performance as an air mover.

SIDE NOTE:  I have to say that the Satori driver chassis look kinda like Illuminator.... and Satori drivers have pretty big allowable excursion numbers too...

[Rick Craig]

I'm going to come late to this thread and post a few thoughts that might be helpful to someone looking at 7 inch drivers and trying to decide what to buy....

One thing to consider about the Illuminator is it has a larger linear excursion, so in theory it could move more air. This means a number of different things, including the possibility of louder bass; also don't forget if you are using EQ at the low end this usually means some boost at the lowest octaves, and so you might benefit from increased excursion.  Just one of many factors to consider.  This excursion difference is one thing you can plug into simulations and so on, so it's a little more 'calculable' than the more subjective aspects of a driver like midrange resolution , etc.

As regards Zaph's measurements, their value comes not from an absolute numerical characterization of each driver in and of itself, but from the ability to compare the drivers he tests to the other drivers he tests. This doesn't give you a definitive picture of the driver's performance, but it gives you important information when comparing these various drivers. Gives you a PART of the picture. Which is a good thing to have when working up a DIY design.

For Zaph's tests of these 7 inch drivers, I like to look not at the absolute numbers of the distortion above 200~250 Hz, but the SHAPE of the distortion results- how quickly does it fall away as frequency rises, what is the relationship between F3 and F2 as frequency changes, and so on.  This gives some information.  What this all means to the overall sound will not be apparent to you until you work with some of these drivers or listen to projects other folks have made using these drivers. Nothing informs like direct experience.  And of course looking at the breakup peak (if any) and it's impact on distortion will influence how you build a passive xover.

SPEAKING OF TESTS I like the kind of tests that Siegfried Linkwitz puts drivers through, which include some dynamic tests (tone bursts) and so on.  Voice Coil magazine also puts drivers through a gauntlet of tests, worth looking at to see if the driver you like has been tested at Voice Coil.  They especially have a lot of "woofer centric" type tests relating to performance as an air mover.

SIDE NOTE:  I have to say that the Satori driver chassis look kinda like Illuminator.... and Satori drivers have pretty big allowable excursion numbers too...

Thanks for your input. It's interesting that in some cases the Klippel tests don't mirror the Linkwitz tests show or vice versa. That's what makes speaker design so complex because you have to understand the tradeoffs.