Driver Evaluations for a new project

[Evil Twin]

Sorry your highness. I am not well versed in appropriate Starwars "ese". I am beginning to suspect that this is a very interesting continuation or slight evolution of the old Mt12a thread....Yes?

A very reasonable surmise, but not a correct one. The Emperor has taken counsel with some advisers who suggest that smaller is better, that the days of the Executor Class Star Destroyer are behind us in these perilous financial times. Though I am not one to agree with him, I must nevertheless do his bidding.... for now.

This project in final form should resemble these....



Hopefully without some of the flaws as detailed here...


Stereophile Review

The designer's "philosophy" -

Asked about his design philosophy, Patel said, "First and foremost is our commitment to musical truth, where all technique is subservient to achieving an ultimate aesthetic goal. What happens in an actual musical event must be preserved and communicated without destroying the subtleties or nuance. Time, which is absolutely invariable in our universe, must be preserved above all else. Technically, this means not allowing phase distortions within or between drivers. All Avalon Acoustic drivers are purely pistonic, with no driver breakup modes within the passband. Phasing is wholly linear throughout the bandwidth of hearing, including the very low bass. Dynamics must have impact and articulation without ringing—which is why the Q of each driver is carefully observed and actively damped, giving amplifiers a purely resistive load (which also eliminates back EMF, which can exacerbate time distortions within the amplifier)."

I leave it to the forum participants to review the technical measurements in the review and decide for themselves how true to this philosophy the speaker system is...

I'll give a "hint" for those who can't wait...




The larger class speakers will be continued based on the methodology being developed for this project; the exact configuration may be modified to a dual driver version with 10" woofers to permit a narrower launch platform for the front panel.

[cjd]

Clearly, "purely resistive" takes its cues from the classic uprising against the empire - starts out slow, loses some steam, peaks a couple times with lots of volatility at its height, following to its final quashing, being ended forever...

[Jed]

Or are you referring to using that motor with another dome assembly and the MCM waveguide?

My tests were with the DXT assembly on a H1212 motor (this hybrid is labeled "DXT" in the graph). Can't tell if that question was directed at me so just in case you want to check it out, this is well documented in the Tombstones thread posted a year ago.

[Evil Twin]

Clearly, "purely resistive" takes its cues from the classic uprising against the empire - starts out slow, loses some steam, peaks a couple times with lots of volatility at its height, following to its final quashing, being ended forever...

Impressive, Chris,..... most impressive. Not even to mention the phase meanderings....


Jed, while away on assignment to the Imperial Remnant, I have been rather out of touch with many threads and topics... please forgive my ignorance this time.

[Jed]

... please forgive my ignorance this time.

The Dark Lord is asking for my forgiveness? ... this must be some kind of trick

[wkhanna]

The only trick I see is arming the Imperial Fleet with a new and immensely powerful weapon that will not only equal and even surpass those used by the rouge rebels from Patelgian and Whatpuppay-8 while at the same time be able to be constructed by us padawans from standard inventory at our remote training locations, but still be of proportion and ergonomics that will be acceptable to our meager sized barracks and platoon commanders.

All Hail the Emperor, his Dark Lord, and empower all his faithful followers!

Black is truly Back, and with Vengeance!

[Evil Twin]

The force is strong in this one.

The only trick I see is arming the Imperial Fleet with a new and immensely powerful weapon that will not only equal and even surpass those used by the rouge rebels from Patelgian and Whatpuppay-8 while at the same time be able to be constructed by us padawans from standard inventory at our remote training locations, but still be of proportion and ergonomics that will be acceptable to our meager sized barracks and platoon commanders.

All Hail the Emperor, his Dark Lord, and empower all his faithful followers!

Black is truly Back, and with Vengeance!

You see more than just the outline of the Emperor's plan, obviously. But there is much more in progress than we are prepared to talk about yet.

Two configurations are planned, with possible sub-variants and component alternatives for both, and far more detailed plans will be available than we have allowed into rebel hands in the past.

[Dennis H]

Phasing is wholly linear throughout the bandwidth of hearing, including the very low bass.

Hmmmm.....

[JonMarsh]

Sometimes people should be careful about what they allow to be quoted and put into print, especially if the product will be tested by someone with solid technical capabilities.

Now, "phase wholly linear" could be interpreted to be something like a Duelund all pass three way, where the drivers are in the same relative phase throughout most of their working passbands.

But the measured behavior in the bass and midrange eliminates that possibility.



Disappointing. Makes me think they cut corners on this one, compared with the Eidolon and Isis, which seem to be fairly solid designs. And cutting corners just isn't something that should be happening with a $20k per pair speaker.

[Dave Bullet]

Lord ET, will this speaker be named in honour of a Sith?

[Evil Twin]

Midrange Driver Evaluations

These tests were done under specific limited conditions, with exceptions to general conditions noted.

The primary test platform is a PE 0.75 cu Ft 8.5" wide enclosure, except for the TB W5-1685 and Accuton C90-T5, which were tested in the 1 cu ft 9" wide PE enclosure, and the Seas W15CY001, which was tested in the NHT Xds ecnlosure.

The drivers were mounted centered on the width, 5 inches from one edge to the driver center.

The enclosure was stuffed with long fiber wool, the same amount for all drivers. All of the test baffles were substantially chamfer relieved on the rear panels to avoid driver masking, except the NHT enclosure.

Measurement distance for axis curves was 18", with SPL normalized to 1 meter. SPL curves were measured with a swept 2.83 VRMS signal, as voltage sensitivity was of greater interest than power sensitivity, and the drivers vary from 4, to 6, to 8 ohms.

Nearfield and distortion tests were conducted at 4"; distortion at 2.83 VRMS drive, and 5.66 VRMS drive, monitored with a wideband HP digital oscilloscope. Due to differences in sensitivity, driver distortion can only be roughly compared; in this case I was more interested in the change in distortion with power at a typical listening level range (87-93 dB typical). Do not compare these measurements to any other measurements, as conditions probably vary.


Dayton RS52an Dome midrange




Family of Curves, 0 degrees, 15 degrees, 30 degrees, 45 degrees




Nearfield Axial Response




Distortion at 91 dB




Distortion at 97 dB



This is a well known performer in most parts of the galaxy, from the Bespin Mines and Napes cluster, to the heart of the underlevels in Coruscant.
Particularly notable are the high voltage sensitivity for an 8 ohm driver, and excellent off axis dispersion. Distortion performance is very good above 1 kHz, also.



Tang Band W4-1337s Ti Cone Midrange



Family of Curves, 0 degrees, 15 degrees, 30 degrees, 45 degrees




Nearfield Axial Response




Distortion at 87 dB Output




Distortion at ~93 dB Output




Off axis response is above average for a cone, and phase linearity is good due to the extended frequency response.



Dayton RS100-4




Family of Curves, 0 degrees, 15 degrees, 30 degrees, 45 degrees




Nearfield Axial Response



Distortion at 87 dB Output



Distortion at ~93 dB Output



This inexpensive cone midwoofer from Dayton has a low profile in most of the galaxy, receiving little notice or attention, while some of it's larger variants are pressed into duty as midrange drivers, an application for which they may be less perfectly suited. The overall frequency response is relatively smooth, with a breakup mode in the 15 kHz area that is trivial for a Sith master to deal with. The off axis dispersion holds up well to about 4 kHz, and the distortion performance down to 300 Hz is admirable for a driver of it's diminutive size. Not a class leader, but impressive... most impressive, and probably a value leader. And it is very, very black.


Tang Band W5-1685



Family of Curves, 0 degrees, 15 degrees, 30 degrees, 45 degrees




Nearfield Axial Response




Distortion at 86 dB output




Distortion at 92 dB output




This is actually a 6" outer frame diameter driver, in spite of it's type number, and one of the larger ones tested. With the additional Sd comes lower distortion in the lower midrange compared to some of the comeptition; as expected, that's also accompanied with a lower turn-over frequency in off axis dispersion, with solid performance to 2.5 kHz that deteriorates above that fairly quickly. Larger and heavier, it requires more rear volume also. The nearfield dip at 1500 Hz is accompanied by a matching bobble in the impedance curve, pointing towards an issue with surround resonance, perhaps.



Seas W15CY-001



Family of Curves, 0 degrees, 15 degrees, 30 degrees, 45 degrees




Nearfield Axial Response




Distortion at ~87 dB Output




Distortion at ~93 dB output




The W15CY-001 has long been known for it's low distortion from 200 Hz to 1500 Hz, with significant cone resonance amplification of distortion products above that.

The off axis response holds up well to 4 kHz, though the usual breakup peak at ~8 kHz requires some work to completely tame.

This driver has been used in a number of costly commercial systems as a midrange; due to their design concepts, employing BSC in the midrange operating band, the overall sensitivity of these systems is usually low.


Accuton 3" ceramic midranges: C88, C89 and C79



The C79 and C89 are distinguished from each other with a number of design details. The C89 (center) has a longer VC assembly and ~25% longer voice coil, and can be used as a midwoofer. The cone mass is about 20% higher, and it lacks the resonance control ears of the C79 on the right. The C88 is discontinued, so test results will not be posted. All three of these require deep chamfering of the rear of the mounting hole to avoid rear wave masking.


C89 Curves on and off axis




C89 Nearfield 4 inches





C89 Distortion at ~90 dB Output



C89 Distortion at ~96 dB Output




Frequency response is linear until the onset of the damped cone resonance at about 6 kHz, where it falls off a cliff; the phase response lags with increasing amounts approaching this point.

The off axis performance of this inverted dome is goo up to 2500 Hz; it deteriorates quickly above that point. Voltage sensitivity is moderately high, about 90 dB/2.83 VRMS.

Though distortion amplification through cone resonance is clearly displayed, the overall levels are still fairly low from 100 Hz up at both 90 dB and 96 dB output.

C79 Family of curves




C79 Nearfield 4 inches




C79 Distortion at ~90 dB output




C79 at ~96 dB output




These improvements in response extension and distortion behavior underline why the C89 is only infrequently seen as a midrange unit compared with the C79. Note that while going from 90 to 96 dB output, HD3 rises little; most of the increase is HD2, which is still fairly low from 300 Hz up. Though resonance amplification can be discerned, it's not an issue regarding the overall distortion behavior, as compared with the Seas and other drivers.


Accuton C90-T6




C90-T6 Family of curves at 1Watt




C90-T6 Nearfield at 2.83 VRMS, normalized to 1 meter




C90-T6 Distortion at ~93 dB (2.83 VRMS, ~1.25 watt input power)




C90-T6 Distortion at ~ 99 dB (~5 watts input power)




The C90-T6 uses a massive neodymium magnet with an underhung voice coil, resulting in relatively high sensitivity- a bit over 93 dB for 2.83 VRMS, while presenting a roughly 6.5 ohm load. The purpose in life of this driver is providing relatively high SPL in a a multi-way system between ~250 Hz and 2500 Hz, with low distortion across most of the spectrum even at 100 db + output levels. Due to it's high price, it is not a high value product unless you are looking for SPL in the 115 dB+ range, and want to do it with only 10-15 watts, while keeping distortion in the range that standard drivers produce at 90-96 db. Higher order distortion is quite low to non-existent, as shown in earlier measurements in the reference threads.

This is being reserved for the ultimate incarnation of the M10ta/M12ta concept discussed a couple of years ago.




Summary & Conclusions

In the low cost class (<$100), the RS100-4 seems to have a slght edge in non-linear distortion, with an acceptably wide smooth frequency response; the main open question is whether it will have adequate voltage sensitivity for the final transfer target function. The W4-1337s is an able performer, but may not justify in some minds double the price of the RS100-4.

The RS52 was including for testing to provide a comparative benchmark, though it's frequency extension in the low end was not considered adequate prior to testing.


In the above $100 class tested so far, sensitivity and nonlinear distortion in the upper part of the operating range are questions for the W15Cy-001, with some extra effort as well to tame it's large response peak.

The C79 seems to have the performance credentials to back up it's choice in a number of high end systems. The C89 is close, but this isn't horsehoes or hand grenades.


Current working target transfer function:

[Evil Twin]

Midwoofer Driver Evaluations

Dayton RS180-8

RS180-8 Axis Curves 0-15-30-45




RS180-8 Impedance



Notice the lack of impedance anomalies below 2500 Hz. While these are often attributed to surround resonances, I doubt that the RS180 has some superior performing surround to the majority of it's competitors- most likely this is due to a lack of midband cone resonance, due to it's exponential anodized aluminum construction.


RS180-8 2.83 VRMS, 87 db nominal




RS180-8 5.66 VRMS, 93 dB nominal




RS180-8 8 VRMS, 96 dB nominal



Classic rigid cone resonance amplification is quite evident above 1500 Hz, arguing for the use of a low, steep crossover point for a two way system, as was implemented in the Natalie P. Overall midrange distortion is low, even at the higher drive levels, and the low frequency performance is very acceptable for it's price class. This is most likely the value leader among those tested.






Exodus EX-6.5




Exodus EX-6.5 Axis Curves 0-15-30-45





Exodus EX-6.5 Impedance



The discontinuity in both impedance curves and SPL response raises some interesting questions about this sample of the EX-6.5- the SPL anomalies are of a magnitude beyond what I would customarily attribute to surround resonances. At a later time, this will be investigated in more detail. For the proposed three way configuration, this aberration is only mildly troublesome.



EX-6.5 2.83 VRMS, 88 db nominal





EX-6.5 5.66 VRMS, 94 db nominal





EX-6.5 2.83 VRMS, 97 db nominal








Now, a short side trip may be in order. One matter which is an interesting puzzle about many of the drivers tested is the variability of distortion levels with frequency, in a pattern which would not be expected to arise from the basic physical factors due to magnetic gap asymmetry, voice coil inductivity, and so forth. Some we are quite familiar with, such as hard cone resonance amplification of distortion products. But still there are other as yet unidentified factors that appear to be at work in the range from 1500 Hz down. We have suspicions about the nature of these issues- consider also the lengths to which S. Linkwitz goes in driver mounting to suppress the resonance of the magnetic assembly and frame and it's influence on the driver output.

Then, let us consider, too, another driver not selected for this test series, due to low sensitivity, but which may have illuminating characteristics to the problem at hand.

HiVi D6.8



Though not clearly evident from this picture, the D6.8 has short frame to basket supports of substantial size- this contributes to some rear masking issues, but also makes the physical connection between the massive flange and mounting system (count those holes!) quite rigid. It seems to be another interesting case of a designer focusing on some particular elements they believe essential to desired audible behavior.

HiVi D6.8 Axis Curves 0-15-30-45



The midband sensitivity of the D6.8 is on the low side, at 85 dB. Possibly this is a factor from the large magnetic gap that must be energized for it's 3" diameter VC. Though using a neodymium magnet, the BL force factor is much lower than many other HiVi models.

Consider the nature of the distortion curve on the D6.8.... perhaps there is reason why I have enjoyed it in smaller systems, and found it relatively "invisible" when used in the right frequency range.

HiVi D6.8 Distortion, 2.83 VRMS



Same cabinet, same conditions, same equipment.





Peerless 830-883




830883 Axis Curves 0-15-30-45


830883 Impedance




830883 Distortion 2.83 VRMS 87 db nominal




830883 Distortion 5.66 VRMS 93 db nominal




830883 Distortion 8.00 VRMS 96 dB nominal



Generally very good midrange performance up to 1 kHz. Some impedance and distortion anomalies in the 1500 Hz area.


Seas ER18RNX




ER18RNX Axis curves 0-15-30-45



ER18RNX Measured Impedance and parameters



A slight bobble in impedance at 1 kHz indicating some kind of mechanical discontinuity, but with little affect in the SPL curve.

ER18RNX Distortion at 2.83 VRMS 88 db nominal




ER18RNX Distortion at 5.66 VRMS 94 db nominal




ER18RNX Distortion at 8.00 VRMS 97 dB nominal




Commendably low levels of third harmonic distortion, especially from 100 Hz to 1 kHz, even at 97dB+ output; as shown, the ER18RNX does have rising output with frequency, possibly due to the moderately low inductance and light weight cone. It would seem that Seas is no longer content for it's Prestige line to be Bantha fodder to Scanspeak and the likes of the Dayton RS180.







Scanspeak 18/8531G



This ScanSpeak driver does not fit the T/S profile for the desired target function for this system, but when a pair were captured in the Bear Nebula and made available for interrogation, this was too good an opportunity to pass up.


18/8531G Curves 0-15-30-45




18/8513G Impedance



As with many other drivers in this test, and typical of Scanspeak cone drivers, an impedance bobble is present just below 1 kHz, indicating some type of mechanical discontinuity. Past investigations have shown this due to cone modes, but the 8531 has not been investigated further yet.


18/8531G Distortion @ 2.83 VRMS 87 db nominal level




18/8531G Distortion @ 5.66 VRMS 93 db nominal level




18/8531G Distortion @ 8.0 VRMS 96 db nominal level




The 8531G for the most part lives up to it's reputation, with excellent levels of third order harmonic distortion at most frequencies of concern, but the impedance anomalies and possibly related distortion artifacts just below 300 Hz create a disturbance in the Force, a feeling that for this level of financial expenditure, one might hope for something a bit closer to perfection.

Of course, only a Jedi would be that naive. Still, at almost three times the cost of the Seas ER18RNX, the value proposition is not consistently clear.
2nd order distortion disappoints somewhat in comparison, though it is still near the top of the class.



Summary and Conclusions:

Considering that the Seas ER18RNX meets the target T/S requirements and provides consistently low if not class leading distortion behavior, at a moderate cost, it may get the nod by the Emperor in this case.

The long time favorite in Rebel sectors, the Dayton RS180-8, puts in a very strong showing, and is an obvious value leader in the class, with excellent fit and finish at a budget price.


Addendum:

ZA14W08

[Evil Twin]

Lord ET, will this speaker be named in honour of a Sith?

Alas, that is not to be. The Emperor has been listening to Marketing lackeys from the revised Naboo trade organization, and the working designation for the project is "SDX-2 Ardent", as in "enthusiastic or passionate"; whether about music or loudspeaker development is besides the point.

[augerpro]

Two more suggestions in that battle against the rebel scum:

Audience 3" midwoofer

Tangband 3" mid dome Preliminary reports from the MarkK cluster encouraging. Zaph will soon be publishing his results (RS52 beater he says) and I'll be following up with some measurements in a waveguide, basically a 1" or 1.25" roundover. Doing the woodwork today.

[Evil Twin]

Two more suggestions in that battle against the rebel scum:

Audience 3" midwoofer

Tangband 3" mid dome Preliminary reports from the MarkK cluster encouraging. Zaph will soon be publishing his results (RS52 beater he says) and I'll be following up with some measurements in a waveguide, basically a 1" or 1.25" roundover. Doing the woodwork today.

Interesting suggestions. Our able informers had brought the Audience A3 to our attention. However, the limitation we see is the unusual impedance (16 Ohms), and low nominal voltage sensitivity (81.9 dB/2.83 VRMS). I can see that in MTM's or in line arrays this component might have some interesting applications. As a single midrange in a three way system, it's parameters seem less optimized.

I look forward to your report on the capabilities of the new TB dome midrange.

[augerpro]

Also Fountek has a new little woofer, the FR88-EX at madisound. One should land on my doorstep tomorrow than off to Zaph for his last ever roundup of drivers.

[---k---]

Wow, the Dark Lord has been busy generating very useful data.

The Dark Lords conclusion about the relative value of the RS100 vs the TB W4-1337 is very intriguing to me based on the popularity of the two drivers. The W4-1337 has quite a following. Based on my experience with Jed's D4, I think the W4-1337 reputation is well deserved. The Dark Lord also appears to be a big fan of the RS52, which seems to have fallen out of favor with many less than fully successful projects. Though they are just opinions and maybe just what is trendy at the moment, I wonder if there is more to it.

[Ray_D]

RS52 Fallen out of favor?

Wow, the Dark Lord has been busy generating very useful data.

The Dark Lords conclusion about the relative value of the RS100 vs the TB W4-1337 is very intriguing to me based on the popularity of the two drivers. The W4-1337 has quite a following. Based on my experience with Jed's D4, I think the W4-1337 reputation is well deserved. The Dark Lord also appears to be a big fan of the RS52, which seems to have fallen out of favor with many less than fully successful projects. Though they are just opinions and maybe just what is trendy at the moment, I wonder if there is more to it.

Ryan

Could you explain your comment about the RS52 having fallen out of favor. I just finished home theater speakers based on Zaph's ZD3C. The center is exactly Zaph's design and the LRs have the TM rotated for a WTMW and I increased the BSC. I am delighted with them.

Ray

[Evil Twin]

Wow, the Dark Lord has been busy generating very useful data.

The Dark Lords conclusion about the relative value of the RS100 vs the TB W4-1337 is very intriguing to me based on the popularity of the two drivers. The W4-1337 has quite a following. Based on my experience with Jed's D4, I think the W4-1337 reputation is well deserved. The Dark Lord also appears to be a big fan of the RS52, which seems to have fallen out of favor with many less than fully successful projects. Though they are just opinions and maybe just what is trendy at the moment, I wonder if there is more to it.

I believe you touch indirectly but importantly on a key factor- designs that are successful become "trendy" and popular, and reward the efforts of a skilled designer. So it is quite likely that a key factor in the popularity of one driver or another of similar performance may come down to whether a talented designer as "adopted" it and propagated it through several designs.

A dome midrange such as the RS52 provides both an opportunity and a challege- it's extended top end may invite one to select a high crossover point, but due to the RS52's large frame size, and the resulting center to center spacing, providing a uniform power response with a high crossover will be problematic. Additionally, because it is just a dome midrange, with some output limitations in the low end, choosing the low frequency crossover characteristics and mating it with compatible drivers is not as obvious a process as it might seem to a neophyte. But as I know from personal experience, this driver does have it's rewards when used well, and can simplify the mechanical design of a smaller three way system.

The largest factor I see mitigating against the RS100 is it's physical design and the potential for rear masking. Careful design of the cabinet front panel is a given.

If you have experience with both of these drivers and would like to comment directly, please feel invited to do so. I do not doubt that the many fans of the W4-1337s are enjoying their systems considerably, but I would be curious to know what anyone who's tried both feels one gets with the TB for 2X the money.

This doesn't mean anyone needs to justify there preference- "it looks cool" is good enough in this day and age- but should the Emperor press me to prepare a "bang for the budget" version with the lowest possible price without compromise, I have to weigh and consider options carefully. The Emperor does not tolerate lapses in judgement or indifferent excuses for bottom line decisions.

[Evil Twin]

Also Fountek has a new little woofer, the FR88-EX at madisound. One should land on my doorstep tomorrow than off to Zaph for his last ever roundup of drivers.

Interesting range of resopnse- I will await Zaph's evaluation. It too, looks a little low in sensitivity to meet the parameters of this project, though, as would the RS100-8.

[cjd]

I've a rather different(ish) design concept in mind for use with the RS100... but that's its own thread, and it may be a miserable failure. I have a couple of the 8ohm versions here and they sound very nice - specs aren't so hot for use in a box but the 4ohm is much better in this respect. I've really liked the numbers on it though. If only I could find a nice sub/sat amp setup in a cost effective range... and with adequate sound quality...

C

[---k---]

Could you explain your comment about the RS52 having fallen out of favor.

Do a search over at the PE forum. It seemed like there was a lot of excitement over the RS52, that slowly died out and in favor of the Morel 3" dome. I think it is much like ET suggests, that the RS52 is a difficult to use and is being pushed on a bit too far. I do think it is also just trends.

I don't have direct experience with both the RS100 and W4-1337, only the RS150 and W4-1337. I've only seen the graphs. One of these days, I'm going to start getting my hands dirtier, taking measurements and designs. Based on what I read on the net, I flip flop back and forth over whether the graphs tell us nearly everything we need to know, or whether the drivers have to be listened to. It is likely just being able to interpret everything that is in the graphs. I often note that the Dark Lord does not provide listening impressions of drivers, which are certainly easier to understand for a young padawan though likely a more difficult task.

[ThomasW]

I think it is much like ET suggests, that the RS52 is a difficult to use and is being pushed on a bit too far. I do think it is also just trends.

We don't do trends.

The RS52 is an excellent driver and a good choice in many applications. It's outstanding in the NeoDcc. The trick is knowing which applications are appropriate for it's performance characteristics.

ET is doing evaluations for some specific applications. The RS52 doesn't play low enough for these particular designs, as a result he's looking at different cone mids.

[Evil Twin]

The right time to judge by listening?

Based on what I read on the net, I flip flop back and forth over whether the graphs tell us nearly everything we need to know, or whether the drivers have to be listened to.

It is likely just being able to interpret everything that is in the graphs. I often note that the Dark Lord does not provide listening impressions of drivers, which are certainly easier to understand for a young padawan though likely a more difficult task.

There are many ways to "listen" to a driver. Once one is accustomed to the signature of a sine chirp, even this test signal may be most revealing of some characteristics during initial testing, especially when generating axis curves.

But ultimately, it's the integration in the system, and how well it is matched to the strengths and weaknesses of the other drivers that tells the story- at this point, you should not be "hearing" a driver, but it should be contributing to a seamless and neutral presentation of the music and it's nuances. It is the difference between hooking up a pair of leads with the output of an stereo amp to a Seas W22 sitting in it's packing box, compared with listening to an Orion system. There are many possible ways to "lose" the magic along the way, and so many steps which must be done correctly to reveal it in the music. The numbers and graphs only tell us what we have to work with, and should hint at possibly synergistic combinations.

[Evil Twin]

If only I could find a nice sub/sat amp setup in a cost effective range... and with adequate sound quality...

C

Pick any one of these two- sadly, both you probably will never find together. I can imagine something along these lines- small, D26CN55 combined with the RS100-4; to make it small, perhaps the RS210HF.

[Kevin Haskins]

I like the look of the RS100-4. I'm going to use it for a flat-panel speaker project. The main attraction I have to admit was the size. The OD is <4" so it fits the form-factor. Second, it looks sexy and the all black design goes well with TV. Third, the price is right, important since I am using three per speaker.

I'm thinking of using an inexpensive 3/4" dome tweeter over 3K or so. Use one of the RS100s as a midbass, and the other two as bass drivers (under 500-800Hz) down the typical HT 80Hz crossover. The design is active but it would officially be a 2.5 way since the midrange would play to the 80Hz cut-off.

The distortion curve looks promising. Three of them should have plenty of SPL for the application I'm targeting and the small size helps with a 3K crossover.

Thanks for the measurements. May the dark side of the force be with you.

[kevinp.]

Nice work ET. I have a three way monitor with the C95/C50/ Fountek Cd3. I kinda wish you had tested the C50 also, but I understand it probably doesn't go low enough for your desires in this project. Rick Craig designed the crossover, so I can't tell you the points or slopes.

[Evil Twin]

We once had a pair of C44/8, as it was originally known, on hand at the Imperial ARDL, for consideration in a future project. They were swapped to MarkK sometime in the past as part of a complex rebel hostage exchange arranged for humanitarian purposes; the details are lost in the miasma of confusion during those chaotic times. You surmise correctly that it's low frequency extension would be no more suitable than the RS52 Dayton driver.
MarkK has some test data comparing both of those, should you be interested. The Accuton has a slight edge in distortion; the Dayton has a large edge in sensitivity, but a larger upper range breakup peak to be dealt with; the Accuton's is at about 20 kHz, and relatively low in level.

Considering the difference in cost, and the high sensitivity, the RS52 is a remarkable value.

[HYPERTUNE]

Any plans to test some of the 3/4 tweeters, considering the use of a relatively small midrange?

Seas T22, Hiquphon, XT19 for example?

A TMWW with XT19, RS100-4 and 2 x EX6.5's would certainly look the part......... 8)

[ch83575]

I don't think I have ever seen it mentioned on this forum, but what about the ATC midrange dome? ATC uses it quit low in their own designs and they really sound great. It also has plenty of sensitivity. Of course it would only work for the expensive version... Or perhapse the really expensive version.

-Chad

[davey_m]

I don't think I have ever seen it mentioned on this forum, but what about the ATC midrange dome? ATC uses it quit low in their own designs and they really sound great. It also has plenty of sensitivity. Of course it would only work for the expensive version... Or perhapse the really expensive version.

-Chad

Availability of the ATC domes, especially the higher sensitivity version, has been problematic recently.

[tf1216]

ATC domes anybody: (not affiliated with the seller)

http://www.diyaudio.com/forums/showthread.php?s=&threadid=143783

[Evil Twin]

Any plans to test some of the 3/4 tweeters, considering the use of a relatively small midrange?

Seas T22, Hiquphon, XT19 for example?

A TMWW with XT19, RS100-4 and 2 x EX6.5's would certainly look the part......... 8)

3/4" tweeters in general offer the possibility of better off axis dispersion than usually provided by 1" tweeters- but with the drawback of smaller radiating area and usually less sensitivity and higher distortion in the range below 3 kHz. Should time permit, I'll test re-test the pair of Seas 22TAF/G which are sitting in storage. My recollection is that this part had a rather severe breakup mode, and mediocre off axis behavior, especially considering the size of the dome. The problematic area for many tweeters is the distortion and power response capability in the crossover region- in this regard, 3/4" tweeters fall short.

If you can point me towards a 3/4" tweeter that has better power handling/distortion and better off axis behavior than the two 1" tweeters identified in testing above, that would be most interesting. So far, I haven't come across one that is capable of that feat.

The Emperor is not forgiving of failure...

[Jed]

Should time permit, I'll test re-test the pair of Seas 22TAF/G which are sitting in storage. My recollection is that this part had a rather severe breakup mode, and mediocre off axis behavior, especially considering the size of the dome. The problematic area for many tweeters is the distortion and power response capability in the crossover region- in this regard, 3/4" tweeters fall short.

The 22taf-g is a nice tweeter--
Straight from a recent post over in my Lineup Maxx L16 Mk2 update:
I decided to test the harmonic distortion of the Seas 22taf-g used in this new design.

Image not available

This tweeter should work really well given my selected 2.5K crossover point, and I could probably go lower just I don't want to stress it too much.

There are more FR plots of this tweeter in my Maxx Build thread. Just in case anyone missed it.



Also, I think you are missing some important information by not testing higher order harmonic distortion. I ran a test on the C173- 90T6 and it has almost NO high order products above 2k. Pretty amazing driver- especially for a hard cone where the main cone breakup usually results in elevated odd order harmonics.... like found in the magnesium Excel drivers for instance.

[cjd]

I like the look of the RS100-4. I'm going to use it for a flat-panel speaker project. The main attraction I have to admit was the size. The OD is <4" so it fits the form-factor. Second, it looks sexy and the all black design goes well with TV. Third, the price is right, important since I am using three per speaker.

I'm thinking of using an inexpensive 3/4" dome tweeter over 3K or so. Use one of the RS100s as a midbass, and the other two as bass drivers (under 500-800Hz) down the typical HT 80Hz crossover. The design is active but it would officially be a 2.5 way since the midrange would play to the 80Hz cut-off.

The distortion curve looks promising. Three of them should have plenty of SPL for the application I'm targeting and the small size helps with a 3K crossover.

Thanks for the measurements. May the dark side of the force be with you.

Very similar to my thinking, except I may go a little funkier.

That reminds me, I have a matched pair of OW1's to do something with...

[Evil Twin]

There is a difference between not posting high order distortion products versus not testing them.


And yes, the C90-T6, or C173-T6-90 as it is now known, is a remarkable driver, but the results I posted for it in 2006, including HD4 and HD5, did show some significant distortion- but this was also at 105 dB levels. But it's overall performance does rate it as a benchmark of sorts for midrange drivers. That was why I included the same basic data for it in this posting as for the other drivers. OTOH, I've heard from contacts in Europe that the penetrated damped diaphragm has been further improved, and resonance amplification of distortion products reduced further.

[Drew]

ET, you have a PM regarding potential inbound rebel scum.

[Evil Twin]

Our communications specialists have already intercepted the message and de-encrypted. Expect a response via the Holonet imminently.

[Jed]

OTOH, I've heard from contacts in Europe that the penetrated damped diaphragm has been further improved, and resonance amplification of distortion products reduced further.

2009 Version:
C173 T6 90

[chrismercurio]

Jed,

What SPL is that? 85db? It looks VERY good though.

[Jed]

Jed,

What SPL is that? 85db? It looks VERY good though.

I'm listening to this driver in a 3way with the Illuminator tweeter and Scan Speak 26W. Quite simply this mid is the most transparent mid I've ever heard......

Well I guess at the price you should get something for the money!

By the way; yes the test was around 85-90db in this box:

[tf1216]

Jed,

How would you compare the 26W to other drivers you have used for midbass and bass purposed?

[Jim Holtz]

I'm listening to this driver in a 3way with the Illuminator tweeter and Scan Speak 26W. Quite simply this mid is the most transparent mid I've ever heard......

Well I guess at the price you should get something for the money!

By the way; yes the test was around 85-90db in this box:

Hi Jed,

Whew! You are definitely in the high end with that combo. I've not heard that particular Accuton driver but totally agree with your comments on the ones I've heard. They simply have a see through quality I've not heard from other drivers.

That said, I about had a heart attack when I saw the price! Unbelievable! How come no love for the C82 or whatever it's called now? It's still extremely spendy by my standards at $275 but it's less than 1/2 the price of this driver.

BTW, I really like your new Lineup Maxx MKII design. The 22TAF-G is a favorite of mine and I'm still in love with the W4-1337. I'm a big Seas fan too. :T Anyway, a very very nice selection of drivers, IMHO.

Jim

[TacoD]

Jed, I do not understand the combo of Scanspeak tweeter with the Thiel&Partner mid. I would rather see an metal cone tweeter. Also with these kind of drivers I expect a cabinet which has bigger round overs, you do not want to introduce edge distortions of the cabinet.

[chrismercurio]

Why not higher sensitivity drivers to match the mid? Or multiple bass drivers are least. Last time I reviewed all of the Scan Speak 8" drivers, they were all very low Qt and all very inefficient.

Out of respect to Evil Twin, back on topic, and I look forward to seeing your survey of bass drivers.