How's this for a dipole baffle?

[oneoldude]

Over 6" of MDF...and that does not include the glue lines!

Now this is a serious dipole baffle. :T

http://www.bd-design.nl/contents/en-uk/d84.html

[cjd]

Well, it's thick, that's for sure.

It's pretty darned narrow for bass response don't you think? In fact, pretty darned not designed for response it seems to me.

What does thick DO in this case?

C

[Landroval]

It's pretty darned narrow for bass response don't you think? In fact, pretty darned not designed for response it seems to me.

What does thick DO in this case?

EQ can fix things. The Orion is even narrower.

[cjd]

EQ can fix things. The Orion is even narrower.

Not the woofers far as I remember the design. . .

[oneoldude]

I guess thick is intended to create a non-resonant monolith. And it may very well do that. Looks good too. :T

But I checked out the 15" drivers they use and one RS 12" HF puts out more linear SPL than both the 15's combined. The 15's only have an Xmax of 3.5 mm. So, no matter what they do with eq. these monoliths cannot play very loud at all.

Also, with the Fostex whizzer as the tweeter you cannot expect much in the HF department either.

But they sure look neat. And I'll bet they are HEAVY! :T

[AJINFLA]

The question is, what does the cutout behind the Fostex look like with a baffle that thick? What does the entire backside look like? There is an awful lot of symmetry going on there :unsure:. Unlike the Orion or Arvo.

Cheers,

AJ

[Dennis H]

The link to the baffle diagram implies all the holes are just cut straight through except for flush-mounting the woofers. Can you say midrange cavity resonance?

[AJINFLA]

I can

[Davey]

I'll bet that thing is pretty heavy!

Davey.

[JonMarsh]

A triumph of perspiration over inspiration.

[Paul H]

You guys are all just jealous 'cause you don't have two 15" dipole woofers per side in your setup

Paul

[AJINFLA]

One of your 15's has more linear displacement than all four of those. Ouch.
At first I thought they were going for super sensitivity ( two 99db drivers in parallel :E ) so that they could use the Jamo passive method of rolling of the top end of the sub, rather than apply boost at the bottom. But, alas, they are powered 8O . Maybe those drivers just have that magical sound within that 3.5mm xmax. Then again, maybe not :roll: .

Cheers,

AJ

[oneoldude]

AJ,

What is it that you see as asymmetrical left to right in the Orion? :huh:

[Landroval]

Maybe those drivers just have that magical sound within that 3.5mm xmax. Then again, maybe not :roll:

Isn't it true that when the cone has to move considerably (you see it move) the distortion increases and the state-of-the-art-guy will say that you have too small or too few cones. I dont entirely understand the need for high x-max.

[oneoldude]

L,

First things first. You listen to speakers with your ears not your eyes. :B

Second, I cannot define what a "state-ofthe-art" (SOTA) guy is. But I know one when I see one. Jon on this board is one. If your standard is the sound of real music recreated in your listening room, be careful who you listen to. I can tell you there are a lot of SOTA pretenders out there. And the shame is, they don't even know know they are pretenders. The speaker above was designed by one. Listen to Jon and the other excellent designers here for great advice. You will not go wrong. :T

Now to answer your question. :W

Xmax is a speaker guy term for the "maximum linear" (front or back) movement a speaker cone can make. "Linear" means with minimum distortion. Virtually every part of a driver is important in that driver's ability to push air back and forth with minimum distortion.

Now why you need a lot of Xmax has to do with good old mother nature. It so happens that the wavelength of sound gets very long at low frequencies. It also so happens that human hearing is quite poor at low frequencies. These two factors combine to cause the cubic liters of air necessary to be moved to hear sound at realistic levels to be very large as frequency decreases and it becomes positively monstrous at extremely low frequencies like 20 Hz and below. Since the volume of air to be moved is measured in liters, it can be calculated by the area of the driver cone mulitplied by Xmax.

In the example above, two of those 15" drivers can linearly move about 600 cm^3 and one RSS315HF - 12" can linearly move about 780 cm^3.

What this means is, if you have these speakers in a box, at 20 HZ the two 15" drivers can linearly put about 96 db SPL into the room and the single RS 12" will do about 98 db SPL (all numbers in this post are half-space). Since most systems are in stereo and in phase at low frequencies, you can add 6 db to those figures for 102 db and and 104 db respectively. Now that may well be all you want. But the speaker above was a dipole.

Dipoles progressively acoustically short circuit as frequencies go lower and therefore produce less SPL. In dipole mode, as used above, the two 15" drivers could linearly produce about 80 db SPL and the RS 12" could produce about 83 db SPL. For stereo the numbers would be 86 db and 89 db respectively. For people wanting to reproduce realistic music or HT sound in the home, that is not enough. The standard for that is that the speakers should be able to linearly reproduce about 110 db SPL across the frequency spectrum so as to reproduce peaks cleanly (even though you are listening at a much lower average level).

To be fair it must be said that many use dipoles only for music and limit the low frequency to about 40 Hz (no bombs, cannons, synthesizers, organs, etc.). At 40 Hz the results are as follows for stereo: 2 - 15" per side - box 114 db - dipole 104 db; 1- RS 12" per side - box 116 db - dipole 107 db.

Keep in mind that these numbers are on the very edge of distortion. If you use more cone real estate you will be working the drivers in a less stressful zone and the system will sound more effortless and more realistic.

Now there are two things left.

The numbers above were generated with Linkwitz' spl_max1.xls program. Go to his site, read it in detail and get that program.

There are a lot of SOTA pretender types out there with tiny speakers and tiny amps who claim all this cone real estate is not necessary. They will play something for you, crank up the volume till it hurts and then ask why you would want anything louder. Trouble is you are not hearing real loudness. You are hearing distortion that you psychoacoustically percieve as loudness. It is not loudness. It is badness. If you do not want the badness, get more cone real estate.

I once made a DIY equivalent of a mini Wilson Max for my home that was tri-amped with 1,800 watts per side. I have had SOTA pretender listeners ask me to keep cranking the volume. The average volumes were so outrageous (above 105 db SPL) that I would turn down the volume to save my ears even though the system was playing very clean with no audible distress. Then they would tell me that their 20 watt tube amps and tiny 6" monitor speakers played louder. Not!

Moral....Be careful when you talk to SOTA pretender types. :T

Hope you found this helpful. :later:

[Rudolf]

Oneoldude,

I´ve followed this nice forum for quite a while - just taking in all that professional advice. But regarding your last posting I have to step in to get some things back into perspective. :B
Your arguments seem to me VERY american: If something is bigger, it HAS to be more powerful - automatically. :E

Did you see the BD15 in relation to the Fostex FE206E used? There is absolutely no need to get more Xmax from those woofers, when the Fostex is crossed in at ~250 Hz. But there are very good arguments to take drivers physically as big as possible:
You "smear" the influence of floor reflections to insignificance.
You get very open backs, that don´t disturb the dipole symmetry. Note how BD stresses the small size of the neodymium magnet.

The Partsexpress website doesn´t reveal much info about that DAYTON RSS315HF-4. Is its cone light enough to take it easily up to 250 Hz? Does it have an underhung voicecoil? If not, you simply can´t compare the Xmax specifications. And looking at the picture: Would you call the backside of that driver really "open"?

So while you CAN argument about the price of those BD15 woofers, you can´t argument about the design of the Quasar. Yes, it´s SOTA and it is professional. :T

If someone is interested in a backside view of the Quasars:

http://www.bd-design.nl/forum/forum_entry.php?id=10329

Rudolf

BTW: I have heard the Quasars (albeit with AER drivers instead of the Fostex) and couldn´t find anything lacking. Very accurate and competent speakers indeed.

[JonMarsh]

You guys are all just jealous 'cause you don't have two 15" dipole woofers per side in your setup

Paul

Only TWO 15's per side? Real men use FOUR 15's per side, in a compound diople (designed this reverse engineered Whisper which ThomsW built with some assistance from moi back in the 90's. Our first big dynamic dipole project Those are special Eton 360 7" midrange, just as used in the Legacy Whisper, but we got rid of the trashy dome mid and planara tweet and used a Focal TC120dx2 instead.





:B

[Dennis H]

Your arguments seem to me VERY american: If something is bigger, it HAS to be more powerful - automatically.

Errrrr..... nationality slurs aside (nice first posting -- good way to win friends :roll: ) people on this forum base their opinions on science, not pseudo-scientific audiobabble. If you had really been reading this forum as you say, you would know that the RS315HF has been measured to be one of the lowest distortion bass drivers ever built and that low distortion continues up into the lower midrange. "Light cones" and "underhung motors" are irrelevant. Measured low distortion is what counts.

[Rudolf]

Errrrr..... nationality slurs aside (nice first posting -- good way to win friends :roll: ).

Well, you see: I just thought I was already part of the family :P
But my apologies for being unpolite in the first place.

... people on this forum base their opinions on science, not pseudo-scientific audiobabble.

Sure? I´ve read a broad mix of arguments here .. from scientific genius to downright nonsense. I´ll try to fit in.

If you had really been reading this forum as you say, you would know that the RS315HF has been measured to be one of the lowest distortion bass drivers ever built and that low distortion continues up into the lower midrange. "Light cones" and "underhung motors" are irrelevant. Measured low distortion is what counts.

Yeah, I should have searched for the RS315HF in this forum and not depend on the Partsexpress site. And I certaiinly agree with your last sentence.
But I do insist that one can´t compare the Xmax of underhung and overhung motors on the same level - the irrelevance of this argument in this case nonwithstanding.

BTW: It makes fun to be noticed from the start in this forum :T

[JonMarsh]

One does get cavity resonances when there is a "pipe" behind the driver. Avalon had to fight that and modify the baffle design; I deal with it in the M8ta by have a substantila conical flare. A straight cylinder is usually the most problematic approach.

Rudolf, as you're apparently familiar with the Quasars, both online and in the flesh, can you link us to some measurements of the drivers in baffles and complete systems? That would be very interesting.

BTW, this is what the RS315HF looks like sort of near field in an 18" wide diopole baffle.



Very well behaved for a metal cone 12, but it didn't surprise me when I got this measurment, as just tapping on the cone with your finger tells a lot of the story - very stiff, no midbass/midrange thunck from bending modes, just a bit of "tink" up high. This measurement was made on a brand new driver with no run-in time- some might prefer a little higher Q, but I think a very small amount of equalization (inline passive) will take care of things nicely.

[Rudolf]

One does get cavity resonances when there is a "pipe" behind the driver. ... A straight cylinder is usually the most problematic approach.

I remember Bert Doppenberg stating somewhere that he had tried a conical opening in the back but had found the "pipe" acoustically more appropriate for the Quasar.

Rudolf, as you're apparently familiar with the Quasars, both onlineand in the flesh, can you link us to some measurements of the drivers in baffles and complete systems? That would be very interesting.

I heard the Quasars last year at an Loudspeaker DIY festival in Germany in comparison to speakers like http://www.visaton.de/english/artikel/art_801_6_89.html and http://www.visaton.de/english/artikel/art_829_6_89.html
and they didn´t sound bass shy at all.
In comparison to the Solitude the bass obviously was less influenced by the room and compared to the "No Box" they were more refined in every respect (no wonder with those AER drivers).
So my experience with the Quasars is not "familiar" at all. I just wanted to step in, when oneoldude didn´t seem to understand the concept of the Quasar IMHO.
Sorry that I could not be of much help

Rudolf

[oneoldude]

Rudolph,

I stand on all I said in my prior post.

Your arguments seem to me VERY american: If something is bigger, it HAS to be more powerful - automatically.

Actually, I did not get my physics training from George Bush and in this case, something smaller (12" vs 15") is better.

There is absolutely no need to get more Xmax from those woofers, when the Fostex is crossed in at ~250 Hz.

There is no problem with the crossover to the Fostex. The problem is in the low bass where the two 15" drivers will run out of steam. It will not be bad if you only listen to chamber music. But if you try to play full scale classical orchestral works or heavy organ works at 4th row center realistic volumes, you will be in big trouble. To clear up this misunderstanding on your part I suggest you study every word in this site: http://www.linkwitzlab.com/ . It is almost a complete education in speaker operation, design and building. You will not find SOTA pretension on that site.

But there are very good arguments to take drivers physically as big as possible: You "smear" the influence of floor reflections to insignificance. You get very open backs, that don´t disturb the dipole symmetry. Note how BD stresses the small size of the neodymium magnet.

Yes life is full of compromises. But two super high quality vertical 12"s crossed at 250 Hz or better will do serious damage to the Allison suck out.

BTW: I have heard the Quasars (albeit with AER drivers instead of the Fostex) and couldn´t find anything lacking. Very accurate and competent speakers indeed.

I'm glad you like them. Buy them or build them.

[oneoldude]

Oh,

One more thing. I decided to compare apples to apples. My prior SPL numbers were estimates with the 12s and 15s respectively squeezed into the Orion speaker. So to be more fair to all concerned, I have tried to be more accurate and put the 12s into the Orion and the 15s in the Quasar MkII. The Orion has a "D" of 483 mm and the Quasar has a "D" I estimate at 390 mm. YMMV.

Here are the numbers:

A pair of Quasars with their two 15s in each dipole as half space:
20 Hz - 79 db SPL
40 Hz - 97 db SPL

A pair of Orions with two RSS315HF-4s in each dipole as half space:
20 Hz - 88 db SPL
40 Hz - 106 db SPL

Ya pays yer money and ya takes yer chances. Which would you prefer?

[oneoldude]

I just wanted to step in, when oneoldude didn´t seem to understand the concept of the Quasar IMHO.
Sorry that I could not be of much help

Rudolf

Grrrr.... Never mind! :later:

[Rudolf]

Actually, I did not get my physics training from George Bush and in this case, something smaller (12" vs 15") is better..

Uuuh, well ... obviously I did not find the right tone on this "american" thing ;x( Sorry for that.

There is no problem with the crossover to the Fostex. The problem is in the low bass where the two 15" drivers will run out of steam.

In the meantime I searched this forum and beyond, but could not find the coil length and pole piece length of the RSS315 in comparison to the BD15. So I can´t argue any further about Xmax.

To clear up this misunderstanding on your part I suggest you study every word in this site: http://www.linkwitzlab.com/. It is almost a complete education in speaker operation, design and building. You will not find SOTA pretension on that site.

I can´t pretend to have studied every word of Siegfried, but I`m quite familiar with that site. And surely no pretension in there.

Yes life is full of compromises. But two super high quality vertical 12"s crossed at 250 Hz or better will do serious damage to the Allison suck out.

I didn´t want to deny that at all.

I'm glad you like them. Buy them or build them.

Being too much into DIY to copy others designs without changes. But I already have some 15" lying around. Too bad I can´t get those RS315 for a decent price here in Germany.

Grrrr.... Never mind!

I DO mind. What went wrong? It would be nice if you could extend your numbers to the Fostex FE 206E in the Quasars and the Seas W22EX001 of the Orion. The Fostex Xmax is 1,5 mm (or 3mm ptp?) compared to the 10mm of the SEAS. So the BD woofers are more in line with the Fostex than the RS315 are.
I surely don´t defend the price of the Quasars - just the appropriateness of the design.

[Dennis H]

The Fostex Xmax is 1,5 mm (or 3mm ptp?)

Good point, Rudolf. The midrange may well be the limiting factor with a 250 Hz crossover. I would imagine the woofers could keep up if they are only playing down to 40Hz or so. Similar concept to the Jamo.

[AJINFLA]

There is an awful lot of symmetry going on there . Unlike the Orion or Arvo

AJ,
What is it that you see as asymmetrical left to right in the Orion?

Left to right? :scratchhead:
Oldude, I'll answer in the form of a question. What do you think is the reason for the Orions funky curved sides shape? Why is the Arvo's backside slanted?

Asymmetry isn't just left right.

Rudolf,

glad you liked the sound. Lets not generalize too much however. Using 2 super HE lowish xmax drivers might have made a little more sense to me if the design was passive like the Jamo. Then the concept of keeping up with, or running out of steam with the fullrange might make some sense with that method of thinking. But they are actively amplified :scratchhead:.
What point am I missing there? Just because it sounds good as is, means that better woofers (for possibly a lot less money!!) shouldn't have been used?
Thats logical? Or are you suggesting that those 2 HE, low xmax, high cost neo woofers are the best choice for ACTIVE amplification? Better than any BMSpro http://www.bmspro.info/index.php?sho...282&id=5047877, Ciare 15NdW1, B&C http://www.bcspeakers.com/index.php?...44&prodotto=51 or 18sound http://www.eighteensound.it/index.as...roduct&pid=232 neo drivers?
I really would like to know what is so special about those 3.5mm xmax drivers. And the tunnel behind the fullrange? Hmmm? "Open" baffle?

Cheers,

AJ

[Rudolf]

Or are you suggesting that those 2 HE, low xmax, high cost neo woofers are the best choice for ACTIVE amplification?

The following is plain fantasy on my behalf:
BD is using those woofers because he already had them as bass woofers for his Oris horns. Simple as that. Serving a high efficiency community of horn lovers with a high efficiency bass is consequent - at least marketing wise. Using those woofers for OB is thrown away money for sure.

But taking a fat baffle and throwing as much woofer cone area on it as possible is scientifically sound IMHO. I would always go for extreme area and decent travel instead of vice versa.

And the tunnel behind the fullrange? Hmmm? "Open" baffle?

Well, sitting in front of the baffle I could not detect any resonance. May be I should have listened at the back of the baffle to know better how it sounded there. Personally I would not dare to put a midrange into such a narrow tube.

Just because it sounds good as is, means that better woofers (for possibly a lot less money!!) shouldn't have been used?

As stated above, the woofer price is very disproportionate in conjunction with the Fostex. But much more Xmax for the woofers would be disproportionate too. So the goal would be not better woofers, but MUCH cheaper ones. If you are going to exchange the Fostex for a more capable midrange, everything else obviously would have to be rethought.

Rudolf
It´s midnight around here - goin to bed :Z

[oneoldude]

Left to right? :scratchhead:

Oldude, I'll answer in the form of a question. What do you think is the reason for the Orions funky curved sides shape? Why is the Arvo's backside slanted?



Asymmetry isn't just left right.

Cheers,

AJ

Since you ask, I will tell you what S.L. personally told me when I personally asked him about the shape of the Orion when it first came out. I did not like the shape and wondered if it could be straightened up. He told me that some folks he knew also wanted to straighten up the lines. He said that there was nothing special about the shape.

He said the shape came about because his wife was tired of square boxes and wanted something more graceful in the house. He came up with the design, she approved it and then he sized it for best dipole results.

He said there would be no acoustic difference in having straight sides if the system was sized and adjusted to give the same effective D as the current design. I understood there might be some mods necessary to the crossover if the acoustic centers of the woofers moved relative to the mid, but he did not expressly say that to me. That is what he said to me and I have no reason to believe otherwise. I have always found him to be an extremely gracious and honest man.

So the "funky" shape was an excercise in Spouse Acceptance Factor, nothing else. :jawdrop:

As for the lack of left/right asymmetry, S.L. seems to believe that there is no benefit from such asymmetry because there will always be diffraction and all you are doing with l/r asymmetry is moving the diffraction problems around. The diffraction is still there. it is basically inaudible and essentially impossible to fix anyway. So why mess with it? If you will note, the Orion has all sort of sharp edges, grill frame space and such that could be done away with if he thought diffraction in the Orion was objectionable. I will assure you, he did think it through carefully and chose not to mess with it. :E

As for the rear shape of the Arvo, Jon has addressed his ideas on that in this forum. I suggest you ask him for further details and refinements. I think it will be most interesting to see his next dipole to see what kind of slant the rear has on it. :roll:

Jon,

Will it have a slant? :huh:

Cheers!

[Dennis H]

If you will note, the Orion has all sort of sharp edges,

Even there, SL may deserve more credit than he gets from the unwashed masses. He doesn't have a smooth baffle with a single sharp edge. Rather, he has a smooth front panel with a sharp edge, a 1/4" gap with another sharp edge, a 3/4" side panel and another sharp edge. In other words, he is spreading the diffraction effects out over an inch of panel width on each side with 3 reflecting points -- not exactly like rounding the edge but more or less the same concept.

[AJINFLA]

Oldude,

I have seen him say on different occasions that the shape is important exactly the way it is, not to be changed.
From Linkwitz Lab, Orion US page:

Wood Artistry is capable of different custom finishes, though this will significantly increase cost and delivery time. Such changes are limited to the Dress panel, Side panel and Grill covers. The cabinet shape cannot be changed because it affects the acoustic performance of the speaker . A variety of different cabinet cosmetics can be seen in the ORION photo gallery.

Maybe its like the question about how many licks it takes to get to the center of a tootsie roll. Either case, whether it is or isn't important, the fact remains that the Orion still looks like this

and the back of the Arvo is slanted. So maybe that dipole in your pics works just fine with that rather symmetric cabinet. But whereas I have seen measurements for the Orion/Arvo, I see none for the Quasar.
Who knows without measurements?
The symmetry certainly has a nice look to it. Might even measure well. Might.

Cheers,

AJ

[oneoldude]

So maybe that dipole in your pics works just fine with that rather symmetric cabinet. But whereas I have seen measurements for the Orion/Arvo, I see none for the Quasar.

Who knows without measurements?

The symmetry certainly has a nice look to it. Might even measure well. Might.

Cheers,

AJ

AJ,

I agree with you completely. And I too think it will not measure very well at all.

I posted the Quasar design simply because the monolithic construction and style were interesting. But I in no way endorse it as a good example of audio design. I simply posted it as a vehicle for discussion.

A few months back, for a friend, I built a dipole pair with the very same Fostex 206E the Quasar uses. Indeed it was conceptually the same idea as the Quasar although I had not seen the Quasar at the time.

A tiny tube amp would drive the Fostex and a self powered sub handled the rest. Passive eq on the Fostex and active crossover between the two. In my friend's case the sub was a commercial box on the floor. It was designed around certain requirements my friend had which included the use of a tiny tube amp, certain space limitations and I had to use his sub.

You will not hear me extoll the virtues of that design. I did not like the result at all and the Fostex left very much to be desired in many ways. But my friend is overjoyed with it. He wants to go into production with it!

However, in order to keep up the sensitivity of the Fostex for the little tube amp, the FR of the thing sucks. No one would would buy it if they saw the FR. My firend knows it. I showed him the measurements. Yet he loves it still! He says it has that old time tube sound and forward presence he remembers from the Vinyl days.

So I guess its different strokes for different folks.

[Rudolf]

I forgot to mention yesterday: BD seems to be much more into "hearing is believing" than "measuring is believing". I´m sure he did not publish any measurements of the Quasars in his forum or in any of the relevant german forums.

I just tried to figure out, how asymmetry on an OB would change the SPL. I simulated the NoBox http://www.visaton.de/english/artikel/art_829_6_89.html in EDGE and looked for a better position of the B200 fullrange driver. Turned out to be at 1 m heigth and 10 cm from the baffle side.
After that I simulated both positions in Boxsim, a Loudspeaker simulation program sponsored by Visaton, the manufacturer of the NoBox. Boxsim is known to give very realistic results with the Visaton drivers.

My findings:
On axis the asymmetric placement simulated better than symmetric. Off axis the benefits are arguable. Differences were confined to the range 200-2000 Hz and did not exceed 3 dB in level.
If anyone is interested in the simulation results, I could mail them to you.

[cjd]

Rudolf, I believe that your results are expected - at least by some of us. Asymmetry will simply spread those diffraction results you can't fix by shuffling drivers over a varying area - a tweeter that is placed on a round baffle with no edge treatment will have diffraction in one spot - go to a square and it spreads out some - move it so it's not even the same distance to each edge, it spreads out more. It's not a solution, it's about minimizing its impact in any one spot. Felt treatment on the other hand... Good stuff.

Off axis is not any more or less than going to a wider or narrower baffle with an asymmetric driver layout. But, the knowledge of how it works can still be usable - at last years Chicago DIY event I set up my MTM's with the tweeter on the outside. One of the audiophiles I later heard arguing about cable lifters chided me, but did ask why - the answer is, of course, simple. It was a large crowd. Off-axis is better on the "wide" side re: tweeter, and when it's NOT just a sweet-spot listening opportunity presenting the resulting smoother off-axis gave a better impression and balance all around. He had simply never thought of that because his mind was in the "one listener in the sweet spot is all there is" place.

Speaker design is always a game of compromises, so the interesting thing is, as often as not, WHY certain compromises were picked as less important than others.

You'll also find a handful of us around here that DO listen to full orchestra and organ, where that 16Hz (32foot pipe) pedal gets used now and again, not to mention the larger bass drums and even the bass viol (~30Hz low point). So, such things are on our minds. We'll just pretend the Australians haven't gone and put a 64 foot (8Hz) pipe in an organ. . .

I mean, I hear people argue that you don't need anything below 40Hz all the time.

This dipole that has generated this thread, I don't think anyone is even trying to suggest it may sound poor (we haven't heard it after all) but are merely using it as we often do as a launch point for discussion on compromises, and as many here seem to be on the same page it often turns into a "what they did wrong" (when it maybe should really be a "what I would do different") discussion. In fact, I have a pair of dipoles I built using no science whatsoever, merely spare parts and lumber. $10(us) invested in the pair. There is something about dipole that evokes that "magic sound" feel and often glazes over deficiencies. At a DIY event a couple years ago people loved the sound. No bass below ~200Hz to speak of, a nifty dip centered around 3100Hz. . .

People buy Bose and think it sounds superb. :P :rofl:

Despite everything, well... there *is* some interesting discussion here.

Hearing IS important, but it can not replace measurements as a basic tool. Measurements, on the other hand, tell you not much about how something will actually sound.

And, some of us are rather sensitive about what is implied in being called "American" these days. 8) Hang in there.

C

[JonMarsh]

AJ,

My firend knows it. I showed him the measurements. Yet he loves it still! He says it has that old time tube sound and forward presence he remembers from the Vinyl days.

So I guess its different strokes for different folks.

Here is the crux of the matter- there are significant sections of what I call "botique" audio who's purpose is to recapture a particular style of sound "production", not reproduction. You friend is enamoured of some very specific sonic characteristics, which can be very pleasant on some kinds of program material, but which can turn into mud with more demanding program.

For the fun of it while at CES this year I sought out some of the more offbeat reproducers (horns, Full range Fostex, line arrays (Pipe Dreams), etc, as well as some well regarded "mainstream" stuff like Dynaudio. I should try to find some time to finish that post (still about 60% of pictures and places unposted), but frankly I'm more interested in measuring and building.

What did come out of those auditions is that these vendors and their audience really do enjoy what those systems do under the right conditions and with the right program material. Heck, if all I listened to was classic jazz recording with limited dynamic range and frequency response extremes, I even liked the better Fostex system that Madisound and Fostex were playing (I wasn't paying a lot of attention to the part numbers). BUT, all it would take is one of my favorite pop or classical recordings to utterly break the spell...

One last comment, when anyone tells me it's how it sounds, not how it measures that counts, there are two responses I have.

1) You're not measuring the right things, or the right way. The right measurements can speak volumes to the parameters that determine audio quality. It's something of a shame that after the pioneering work of Richard Heyser at Audio magazine, we only have one publication left in the US of A doing any serious speaker measurements (the simple frequency plots in HT Magazine don't count, though they're better than nothing and often reveal much more than the system manufacturers would like to see published), and even there I doubt John Atkinson is doing what he COULD be doing, based on his knowledge, as it would probably hack off too many of their advertisers. So, it's SL and the body of DIY practitioners that are carrying the torch for driver and system evaluations.

2) You like colorations of a specific type, and may as well own up to it. Sound production, not reproduction. Everyone has a right to make that choice and listen to what they want, but they also need to "own" that choice. (yes, I was a psych major in school, not EE). The attachment can be largely emotional due to a postive experience at a younger age, or simply a very different "esthetic" about what audio/music entertainment involves.

And of course, don't take these pronouncements on my part too seriouisly, as we all know I'm just a nutball Luddite amateur who has an excessive fondness for flux capacitors... unless my schizophrenic side comes out, and we don't want to go there this morning. :E

[AJINFLA]

So I guess its different strokes for different folks

Oldude, always will be :T . And lest we forget, this isn't brain surgery, it's the enjoyment of music. Take it only so seriously. I don't fool myself for a second that my own speakers would sound any better to someone who likes Fullrange drivers than something like this Quasar would sound to me. No I haven't heard it, but I do know what Fostex and many other fullranges sound like.
Oddly enough, part of the allure of the fullrange is something I favor. I just think that some of their attributes are misplaced. I believe a lot of the "magic" has less to do with the lack of crossover and more to do with the point source nature, coupled with the same (cone) material properties throughout the passband. It's not coincidence (no pun intended) that the TAD I'm enamored with uses the same materials for both drive units.

Rudolf, I have used both the Edge and FRD programs, but call me old school(like SL -and Jon :W ), I still rely almost entirely on measurements rather than model simulation tools. Especially when it comes to dipoles. Until those programs can account for the rear radiation (shape) of the driver and how it sums with the front - in the far field, I will continue to use them sparingly.

CJD, what's the saying? I'd rather have it and not need it, than need it and not have it. My feelings on below 40hz bass or just about every performance paradigm you can apply to loudspeakers. No I don't have an unlimited budget. I just choose to apply a portion of my disposable income towards getting a relatively high level of speaker performance. In my mind at least :B .

Jon, couldn't have said it better. I think we share the goal of making a speaker that sounds less like a "paper cone in a box romanticism" and more like the musical instruments we hear in real life - no matter how ugly that may end up sounding . The notion of a speaker that is "too revealing" or "too accurate" is rather absurd to me. If a loudspeaker is accurate enough to reveal all - and you don't like what you hear, blame the recording not the speaker! If a speaker makes a bad (harsh for eg.) recording sound good (smooth), somethings terribly wrong.
If I were to host a DIY event, it would be mandatory to have some real musical instruments there, to remind the delusion that a real cymbal strike doesn't sound anything like what you get from a (fullrange) paper cone :blink:.
Heck, bring a whole band ;b>
What better way to test, resolution, accuracy, soundstage, yadda,yadda,yadda

Cheers,

AJ

[JonMarsh]

Amen, AJ.

[oneoldude]

.......Take it only so seriously. I don't fool myself for a second that my own speakers would sound any better to someone who likes Fullrange drivers than something like this Quasar would sound to me......

Jon, couldn't have said it better. I think we share the goal of making a speaker that sounds less like a "paper cone in a box romanticism" and more like the musical instruments we hear in real life - no matter how ugly that may end up sounding . The notion of a speaker that is "too revealing" or "too accurate" is rather absurd to me. If a loudspeaker is accurate enough to reveal all - and you don't like what you hear, blame the recording not the speaker! If a speaker makes a bad (harsh for eg.) recording sound good (smooth), somethings terribly wrong.

If I were to host a DIY event, it would be mandatory to have some real musical instruments there, to remind the delusion that a real cymbal strike doesn't sound anything like what you get from a (fullrange) paper cone :blink:.

Heck, bring a whole band ;b>

What better way to test, resolution, accuracy, soundstage, yadda,yadda,yadda

Cheers,

AJ

AJ,

I agree with you completely. You and Jon have described my beliefs regarding our mutual hobby to a "T". Both of you said it better than I could. :T

Perhaps that is why we are here talking to one another. Hmmm. :dance:

Later

[JoshK]

I think this philosophy is shared by many on this board, and why I was attracted to Jon & Thomas's projects (and others). I share the same philosophy and I know of noone better to learn about speaker building from that shares the same values then those here.

[Jack Gilvey]

Damn, that looks nice. I've got to use them for something...

BTW, this is what the RS315HF looks like sort of near field in an 18" wide diopole baffle.



Very well behaved for a metal cone 12, but it didn't surprise me when I got this measurment, as just tapping on the cone with your finger tells a lot of the story - very stiff, no midbass/midrange thunck from bending modes, just a bit of "tink" up high. This measurement was made on a brand new driver with no run-in time- some might prefer a little higher Q, but I think a very small amount of equalization (inline passive) will take care of things nicely.