What are your favorite extended range drivers?

MJK · « **Reply #60 on:** 30 Sep 2007, 08:18 pm »

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All narrow speakers suffer the effect, I think and most designers simply assume it part of the over all design.

Agreed, the key word here is designers. However, most DIY single driver hobby types don't have a clue and end up wondering why the speaker sounds thin or making up excuses as to why it is really better that way.

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The solution using altered drivers or comp networks is not a good solution in a single driver speaker. And all the talk in the world about them and how to deal with it will not fix it. Those pesky laws and the amount of what I'll call "excursion distortion" that any single driver will have can not be overcome.

Obviously I don't agree. I have not had a problem with excursion of my Fostex of Lowther speakers with a BSC in place. They play the music I like plenty loud without showing any signs of distress or distortion. They will go significantly louder then I would be comfortable listening to for any extended period of time. I have plenty of power to drive them to any level, for acoustic music they work very well. I will admit that I have not tried them on any of the selections you mention, but I would not anticipate any issues.

MJK · « **Reply #61 on:** 30 Sep 2007, 08:34 pm »

Duke,

Quote from: Duke on 30 Sep 2007, 08:10 pm

I would think that backing a speaker up against the front wall only simulates the baffle-step-region-and-below behavior of a bipole; it doesn't accurately simulate the relative intensities and arrival times of the direct versus reverberant energy.

I think it would be an approximation of a bipole speaker without a rear wall, the phantom rear driver would radiate backwards to infinity and only the wrap around would come to the listener, this wrap around would be equal to the reflection from the front driver's wrap around response.

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Regarding that rear wall reflection - James M. Kates in his article entitled "A Perceptual Criterion for Loudspeaker Evaluation" (supported by other articles since then) showns that the ear's sensitivity to tonal coloration from a reflection peaks at about 2 milliseconds delay and has tapered off significantly by 5 milliseconds, so if the rear wall reflection arrives much later than that its detrimental effects should be minimal. With dipoles (which I sell), I shoot for a delay of at least 10 milliseconds - which isn't always feasible, in which case I try to diffuse or (as a last resort) absorb the backwave. My understanding is that with enough path-length-related time delay, reflected energy is classified by the ear/brain system as "ambient energy", rather than fusing with and distorting the direct sound.

So for 2 millisecond and 10 millisecond delays, the distance to the rear wall from the baffle would be :

1/2 x 0.002 sec x 344 m/sec ~ 13 inches

1/2 x 0.010 sec x 344 m/sec ~ 68 inches

if I have done my math correctly. I can definitely do the first delay in my room but the second value would require a much larger room. I guess I am not ready to dismiss the rear wall reflection and its audibility in my situation just yet.

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Even after optimizing the bipole, the big question would still be: Can $X spread among all the drivers and complexity required for a bipolar system sound as good as that same $X spent on a more conventional system? The answer may vary from one person to the next.

I agree completely with that discussion. This is also the reason I don't care for MTM systems, I would rather buy two better drivers then the three required for the same price. Now if you are already buying the best and can afford more drivers, more power to you. I have always wanted to use a few of my Lowthers in a bipole just to try it out but I never have the time or energy to build the enclosures.

Martin

Ed Schilling · « **Reply #62 on:** 30 Sep 2007, 09:03 pm »

Martin, Yep, designers. We agree again. Scary.

Loud for you may not be for someone else. And loud little girls with acoustic guitars is way different than club like volumes in a large room.
I do not doubt that your speakers sound good, to you and I do not doubt they go loud enough for you. I gave away pairs of single driver TL's one year for Christmas. They were very inefficient, relatively speaking but they sounded great. The people that got them all thought they went plenty loud enough too. I used to get comments on how "big" they sounded for such a tiny speaker. Compared to my "favorite" speaker they simply were anemic. When I say loud, I mean live, drums make you jump, 105 dB peaks on the SPL meter at your listening spot. And sometimes that is needed. Here is a nice image of what I consider "loud". This is a peak level, obviously. and this would have been taken at the listening spot. Notice the bar graph and the setting. The average level is around 100. I just happened to have hit the camera at the instant it hit the peak. Don't remember the song.

It is nice we are in agreement on some level anyway........

Ed

Duke · « **Reply #63 on:** 30 Sep 2007, 09:26 pm »

Martin,

I really don't know you of course, but you and your math are essentially world famous... so when I read:

"if I have done my math correctly"

I didn't know if you grinned to yourself as you typed that or not, but I sure grinned when I read it!

Cheers,

Duke

MJK · « **Reply #64 on:** 30 Sep 2007, 09:50 pm »

Duke,

Quote from: Duke on 30 Sep 2007, 09:26 pm

I really don't know you of course, but you and your math are essentially world famous... so when I read:

"if I have done my math correctly"

I didn't know if you grinned to yourself as you typed that or not, but I sure grinned when I read it!

Thanks for the compliment. I wrote that in total seriousness, I never assume that I am incapable of screwing up. Just ask my wife and kids (typed with a big grin). I mess the math up occasionally, more times then I would like to admit.

Martin

jrebman · « **Reply #65 on:** 1 Oct 2007, 12:29 am »

Folks,

Since this is straying from the original topic I've created another thread here:

http://www.audiocircle.com/index.php?topic=45807.0

Where I ask you all to continue this discussion. Please don't stop here, this is really great and I'm learning a few things on my journey from amateur to "designer"., as I hope others are as well.

Welcome also to Duke and Ed -- glad you guys are adding your substantial expertise and points of view here.

Ed, where do you get bird shit cone drivers?

.

-- Jim

PaulFolbrecht · « **Reply #66 on:** 3 Oct 2007, 06:12 pm »

Wow; I just discovered this circle after 2+ years of AC! aa

I love the AERs in my Lamhorns. I've loved Lowthers in the past but the peak always gets to me, on some music. Even modified ones like Rethm uses - still there. The AERs are, in fact, just a tad less immediate but it's a very happy tradeoff for the TOTAL lack of a presence region peak.

jrebman · « **Reply #67 on:** 3 Oct 2007, 06:18 pm »

Paul,

Welcome, and I'm jealous of those Lamhorns. Those are my all-time favorite single driver speakers, and if I had the money I'd order a pair today.

Thanks for jumping in.

-- Jim

PaulFolbrecht · « **Reply #68 on:** 4 Oct 2007, 02:55 am »

Jim - I shouldn't tell you this since I'm a Norvinz FR and sell them, but there was a pair on agon as of yesterday. Don't see them often, that's for sure.

raov1 · « **Reply #69 on:** 4 Oct 2007, 06:19 am »

Fertin 20ex ..

jrebman · « **Reply #70 on:** 11 Oct 2007, 05:37 pm »

raov1,

Those look cool. Too bad they are out of my range

. I wonder how they compare to the Feastrex and Supravox drivers.

-- Jim

floobydust · « **Reply #71 on:** 17 Oct 2007, 03:35 am »

Well, back to the original question.... I built up a quick pair of 10-litre enclosures and have them loaded with the Fostex FX120, which nobody else has mentioned so far. Overall a very nice driver with a die-cast frame and large ceramic magnet. I also have a new pair of Fostex F120A drivers which I'll build enclosures for once I get some free time. While both are only rated at 89dB at 1-watt /1-meter they still play very loud with my 2-watt 45 triode amps (they put out a solid 2.25 watts)... and they sound very nice indeed.

The Quad ESL-63 is probably my favorite single driver speaker... but that's cheating a bit as there are 4 panels in each (but a single dustcover). The sound with the 45 triode amps is amazingly detailed and open but they just don't get that loud.

Regards, KM

AK · « **Reply #72 on:** 17 Oct 2007, 07:02 pm »

FR125S is my favorite, I wanted to put them temporarily instead of fostex fe127.
and I never put fe127's back. Only converted speaker boxes to aperiodic. FR125S is amazing driver.

jrebman · « **Reply #73 on:** 18 Oct 2007, 05:42 pm »

I'd like to hear more about both the fostex 120s and the FR 125. I've been considering the FR 125 for a possible project, but at this point that will be a long while down the road.

-- Jim

mcgsxr · « **Reply #74 on:** 18 Oct 2007, 06:13 pm »

I have a set of the FR125's. I posted somewhere in the DIY Cable Circle, my build of their KIT41 (using the WR125 and a tweeter) and later the comparison of the FR125 alone. I prefer the FR.

Great little driver, but needs some power to get it going, as it is only mid 80's efficient. Not perfect top end, but very listenable. I use a pair in a mostly sealed box, for my family room radio speakers.

Excellent build quality, simple to use, and rewarding to build with!

Love my b200's more though...

Derockster · « **Reply #75 on:** 19 Oct 2007, 02:45 am »

I love the fostex 208 sigma in my Jericho Horns.

Mister Pig · « **Reply #76 on:** 21 Oct 2007, 03:02 pm »

I have a pair of Audio Nirvana Super 12 in a set of cabinets that Jason at Lovecraft Designs built for me. Wired them up with a silver ribbon wire from Audio Magic. I find the high frequency response better than any of the moderately priced Fostex drivers I have owned. Bass response is respectable. It can be a bit forward sounding, but overall its a nice driver for a modest price.

Regards
Mister Pig

floobydust · « **Reply #77 on:** 21 Oct 2007, 03:22 pm »

The Fostex FX120 and F120A do share some common pieces. First and foremost are the die-cast frame. This is a nice upgrade from the cheaper Fostex single drivers and certainly adds to the cost over your basic stamped-steel frames used in the FE and FF series. This alone contributes to the much higher cost. Second, the cone and surround look very similar and are made from Kenaf but the F120A cone is black on the front (still white on the rear) and the aluminum dustcover appears the same. The main difference is in the magnet assembly, the FX120 uses a ceramic magnet with a rubber ring around it while the F120A uses an Alnico magnet in a cast housing which is smaller in diameter.

One of the most interesting facts on both of these drivers is their exceptionally flat response with the FX120 being a bit more extended in high frequency range but beyond that they are very similar in response. Of course the F120A costs over double the FX120 due to the cost of Cobalt being so high making Alnico very expensive to produce.

Sonically, I have found the FX120 to be an excellent driver in most respects relative to it's size. Size is important here... the cone size allows for a wide range response without sounding fatigued and one of the best qualities is you don't get the upper midrange "shout" like the FE126 and other similar Fostex units. Despite being a solid 4dB less sensitive (than the FE126) I continue to find that the smaller drivers should not be pushed to high SPL levels as they all tend to distort. Asking for more than about 92-95dB output is more than you should (IMHO) so using a mere 2-watts is more than adequate. If you want high SPLs, look elsewhere.

Regards, KM

jrebman · « **Reply #78 on:** 21 Oct 2007, 03:41 pm »

KM,

Thanks for the pointer to the fx-120 -- didn't know this one existed. It looks like it will, at least in most circumstances, be a drop-in replacement for the FE-127, and while the mounting flanges are different, the cutout is the same. Qts is essentially the same, as is FS, and VAS is a little different, but probably not enough to make much difference in anything but a critical Q enclosure. At least this is how I'm slowly coming to understand these things.

Thanks,

Jim

floobydust · « **Reply #79 on:** 22 Oct 2007, 01:38 am »

Jim,

Not sure if I would simply sub this one for another based on T&S parameters alone. Fostex has recommended enclosures for all of their drivers but I have found slight variations from what you can download from their website (which is the same PDF as Madisound) and the actual printed sheet enclosed with the driver itself. In some cases there are different enclosure setups altogether. In all cases the FX120 and F120A are only recommended in a ported enclosure of about 10 liters.

On interesting enclosure design is the OneZ done by Audio Crafters Guild... link is:

http://www.audiocraftersguild.com/Loudspeakers/oneZ/oneZ_summary.html

While they certainly do recommend the F120A as one of the possible drivers, an email with them around the FX120 driver had them recommending a different (aka, more common ported) design and not the OneZ enclosure.

On a side note, Fostex is effectively discontinuing the F120A due to the high cost (Alnico). According to Madisound they still have parts to build more (quantity unknown) per special order from an authorized dealer/distributor. Overall probably a shame but with the FX120 being so good at less than half the price of the F120A it's tough to determine just how many can be sold at this high price. In any case, when they're gone... they're gone.

Regards, KM