Two K33 Questions

[Albatross]

Hello everybody

I read this forum a lot but haven't posted in a while...Seasons Greetings!

Question one: My hard drive died so I lost my link to a particular thread that had PWK's parameters (specs) for what makes a good k33 ( it might have been woofer in general) for him? I'm not talking about any particular k33 but all incarnations of k33 when Klipsch went out to buy a woofer..

Question two: can one explain the sonic characteristics of higher xmax. My guess is more punch since their is more air movement, but I don't have the expertise that some of you do in this category. I ask this because I like the sound of the Cornwall's bass, but am intrigued by the Great Plains Altec 515 8LF. The altec has a xmax of 5mm where as the k33 is in the 8's. I have also read in the forum mixed reviews on both (aren't forums great..." I love rocky road!" "I hate rocky road!")

Thanks for any info.

Spencer

[Jsaint]

This is what I know, XMAX is correctly measured in one direction not sweep, more Xmax = more air movement as you assumed. The frequency response is altered by Xmax changes. If you were just using a woofer for low notes (I.E. a subwoofer) Xmax is king but higher frequencies will suffer seeing it will take more time to move the longer stroke. I would stay with the design specs unless you plan to change other drivers and the crossover. I will let smarter folks prevail from here.

[Chris A]

Hi Spencer.

Question one: My hard drive died so I lost my link to a particular thread that had PWK's parameters (specs) for what makes a good k33 ( it might have been woofer in general) for him? I'm not talking about any particular k33 but all incarnations of k33 when Klipsch went out to buy a woofer..

http://forums.klipsch.com/forums/p/64175/627641.aspx

Question two: can one explain the sonic characteristics of higher xmax. My guess is more punch since their is more air movement, but I don't have the expertise that some of you do in this category.

Basically, it''s the design maximum displacement of the cone. The following is from another thread on another forum:

"Large signal parameters:

These parameters are useful for predicting the approximate output of a driver at high [output] levels.

• Xmax - Maximum linear peak (or sometimes peak-to-peak) excursion (in mm) of the cone. Note that, because of mechanical issues, the motion of a driver cone becomes non-linear with large enough inputs, ie those in excess of this parameter.

• Xmech - Maximum physical excursion of the driver before physical damage. With a sufficiently large input, the voice coil and cone will cause voice coil damage or to some mechanical part of the driver.

• Pe - Thermal power handling capacity of the driver, in watts. This value is difficult to characterize and is often overestimated by manufacturers and others.

• Vd - Peak displacement volume, calculated by Vd = Sd·Xmax

Read more: TS Parameters (Thiele/Small Parameters)"

Higher Xmax means that the driver can push air through a larger stroke: think of it as a long-throw crank in an internal combustion engine. What is the effect of larger Xmax overall? Well, it means the driver pushes more air at larger inputs, but it also produces higher intermodulation distortion when doing so...remember the saying: "Anything that moves--distorts." Having a woofer with larger Xmax in your Cornwalls will probably not be desirable since there are usually many other factors that are coupled to having higher Xmax - such as the compliance, the moving mass, the driving force available (i.e., coil windings and permanent magnet field strength, etc.), electrical impedance, etc..

I think you will need something like Hornresp or some other freely available speaker design tool to plug your candidate-driver Thiel-Small (T/S) parameters into--to see the effects on overall bass bin performance, including (but not limited to...) frequency response, phase response vs. frequency, impulse response, maximum output vs. frequency, required electrical input, and back-EMF properties.

PWK did a really good job of matching the K-33 performance to the box, and I'd say you'd be somewhat hard pressed to dramatically improve (that is, significantly improve for the money invested) its performance.

Drivers can also be very expensive but not be what you want in the box to match with your midrange horn/driver, tweeter, existing passive crossover network, and driving amplifier.

Chris

[Albatross]

Just wanted to thank both of you for your replies. The xmax info was helpful to the max (couldn't resist). I want to keep that West coast Klipsch sound, but will be building a Cornscala so was looking at All my possibilities ie Crites woofer, K33, but other higher end ones including one from Great Plains Audio/Altec 515 8LF (hearing mixed reviews, but look like they go down to 20hz).

I have seen the link you sent me before in regards to K33 specs, this one is helpful , but there is one out there that talks about how Paul W Klipsch picked certain parameters when purchasing a new k33 from a vendor (Eminence, University etc.).

Good listening

Spencer

[djk]

"but look like they go down to 20hz)"

Only under the influence of drugs, it's a great mid-bass driver.

Thiele-Small Parameters:
Xmax (inch) 0.20
Re (ohms) 6.70
Vd (cu. in.) 23.00
Fs (Hz) 27.40
Vas (cu. ft.) 16.60
Ref. Eff (%) 6.70
Qts 0.255
Qms 11.63
Qes 0.261

[Albatross]

DJK

I read a decent amount of threads on here and have enjoyed many a person's insight. I have read a decent amount of your posts ,as well, since I feel you actually don't speculate, but are experiential in your pursuit of good sound, ie. you experiment with drivers and do A/B testing. I'm wondering if I could pick your brain on the topic of Cornscala's and beyond? I have a pair of Cornwalls , 1974 (square magnet), Atlas mid etc. These speakers are great fun...I've had a decent amount of high end speakers in my life (Thiel's, Totems, Paradigm Reference, Martin Logan's... all were enjoyed) but I've always been somewhat analytical with my listening of these, where as, with the Corns I sat back and enjoyed the music and they certainly passed the toe-tapping test. Granted they were being played on good gear, Bryston B100.

I'm intrigued with the idea of Cornscalas, because if PWK was a master of getting good sound from inexpensive parts, what would it sound like to throw in some higher costing parts. I am in a holding pattern, because there is so much info out there about this driver or that one. I can't make up my mind on what to do. I like the idea of a two way with the GPA 902, but feel like I might not get that sense of air on the top in, so might want the Beyma CP25(three way). I like what you have to say about the community 200's midrange (although a little $$$ steep for me right now). Met a guy in Portland Oregon that make's Paper mache' horns who had a pair of JBL 2446's on them...sounded great. Then there is the woofer category Altec 416, Crites, Eminence Kappa Pro-15LF-2.

I have purchase a Altec 511b, the Selenium D250X and the Eminence APT 200 (unfortunately, the new version) as a stop-gap 2 box cornscala project, figuring I could change out to better later (still haven't built these yet).

So, to make a long story short...the Driver menu is much too large for me to make a decision. You have a great knowledge base and seem to know musicality.

If you were building a good, better, best (the ultimate) cornscala what would the three driver/horn compliments look like, and why the choices? If you are willing to take the time, I thank you for your help and expertise.

[Albatross]

There has to be a way to get separate paragraphs when writing on this forum since I'm seeing it done...any clues, anyone? [:@]

[Marvel]

There has to be a way to get separate paragraphs when writing on this forum since I'm seeing it done...any clues, anyone?

Are you using a Mac? Safari and Google Chrome aren't to friendly with the Klipsch website.

You can use Firefox, which would resolve the issue. If you want to use Safari, you have to manually insert the line breaks. You can do this by inserting a < br > with NO space between the < and the b and no space between the r and the >. This will insert a BREAK in the lines. If you type it once you can copy and then paste whenever you need it.

It's a pain but it works.

Bruce

[mustang guy]

There has to be a way to get separate paragraphs when writing on this forum since I'm seeing it done...any clues, anyone?

Try one of these:

Install Xstandard:

http://www.xstandard.com/

Edit Profile

Site Options

Content Editor: XStandard

or

Install Firefox

[Albatross]

Yes, Mac, yes Safari...Thanks for the solutions

[JBryan]

Yes, Mac, yes Safari...Thanks for the solutions

I also use a Mac with Safari which the gatekeepers at Klipsch do not support well or perhaps this site is a bit long in the tooth. I use a P, between a 'less than" symbol and a "greater than" symbol to separate paragraphs.

[Albatross]

Thanks JB

Thats an interesting speaker on your icon. Is it a Klipsch Corner horn mod (cornerhorn bass box)?

I'd like to open up the question I asked DJK to others that have heard good upgraded drivers. Looking for smoothness in the mids and highs (not bright) yet not dark or veiled either, and a sense of air on top. I like the sound of the square k33 mid-bass, but am not sure what more dollars would bring me . Be as subjective and descriptive as you want in your impressions.

[Albatross]

Thanks JB for the info...the lessthan/more than "p" fix worked. All the other ideas from other folks might work too just haven't tried them yet.

I should have looked at your equipment list, before asking you about what your icon . I thought I recognized the horn. How does the BD integrate with the Kornerhorn bass? I've been drooling over the Swings, they look like beautifully made speakers.

[Marvel]

the lessthan/more than "p" fix worked. All the other ideas from other folks might work too just haven't tried them yet.

The 'p' means paragraph. the 'br' means line break. Either will work.

Bruce

[WMcD]

I'm not aware of any publication by PWK where he describes the choices of specific parameters. If you can give any information or hints, I'd be happy to hunt it down. I like doing that.

In theory, whether you need a given x-max depends on the application. You can use various programs to look at x-max in box designs. These show, generally that there is a vast difference between a sealed box like a Heresy and a ported box like a Cornwall.

In a sealed box: Lets go down from 100 Hz toward mechanical system resonance. The displacement increases as we go down to resonance where it becomes a maximum, and then decreases. This decrease is is because the spring caused by the box is preventing it from moving.

But you see movies and the like of woofer diaphrams moving wildly in time to the bass note. That is the big displacement at mechanical resonance of the combination driver and sealed box.. Also, this is sometimes because the Qes of the driver is high, meaning it is underdamped. But, in any case, x-max is being challenged because the highest diplacement occurs at system resonance. Of course with more electrical power, and higher acoustic output, x is greater overall. You can run out of x-max. We also see the electical impedance rise to a hump. We see this in a driver not mounted in a box.at Fs of the driver.

In a ported box: Again you have to look at x in a simulator. Physically, the box plus port forms a resonant mechanical system which is excited by the rear of the driver. There are various "alignments" which describe the many relations between possible drivers and possible box sizes and port sizes. One or two of the alignments (IIRC). put box/port resonance at exactly the driver resonance. Other alignments move the box/port resonance a bit below or above.

In any case, the advantage of the box/port is that over a limited range of frequencies, the box/port acoustically "loads" the back of the driver and the bass sound comes out the port because the slug of air in the port is moving. In the sealed box, we don't have that effect. We're kinda getting a bump in the bass response for free by loading the back of the diaphragm.

But, if we look at displacement x. of the driver in this situation, we see something very different than the sealed box. Displacement at system resonance is very small, rather than large. This is because the woofer is being loaded by the box/port and doing more work. X-max is not being challenged nearly as much. Unfortunately, below system resonance, the box/port does not load the driver and x increases (maybe beyond x-max) and you can bottom out the woofer. It will make an odd clank or crackle.

You can see some this port effect in the electrical impedance of driver in a ported box. Remember that in sealed box and unmounted driver we see a fairly smooth hump at system resonance. With the ported box, we see the acoustic loading create a somewhat sharp valley right were the hump in electrical otherwise would reach a smooth max. Now there are two sharp peaks to the sides of the valley.

WMcD

. .

.

[Albatross]

Thanks for the info WMcD...I am beginning to understand xmax on a whole different level. The question arose when I began looking at the Great Plain Audio, Altec woofers.

I've heard both good and not as good things about them compared to the K33 or the Crites woofer. I want to keep the slam of the square k33 that I have, but am curious about the 515 8LF or the 416 ( not sure which is better between these two for my cornscala application) because they look like a very well made speakers. I was wondering if the lower xmax on the Altecs means lower punch (or dynamics).

What does a higher end woofer do for you (other than lower bass). Can you get a tighter bass , but not lose that 70's sound?

I have been wondering what a Cornscala with an Altec Woofer, Altec 902 or Community M200 mid-range, and a Beyma CP25 (or others ) would sound like.

[WMcD]

Albatross (are you into sailplanes?):

I think you are best off sticking with the K-33. BTW, I don't know what the '70s sound really means. At one point in time there was the use of the term West Coast sound which IIRC was supposed to be a bit bright in the treble in a good way..

Altec is a big name in speakers. OTOH, it a big misconception that pretty looking woofers, or woofers with big magnets,or hefty basket structures are better than others in all or even a specific application. Looking "well made" does not mean that a driver is better for any given application. It seems to me the Altec were designed for their Voice of the Theater horns.

It appears to me that you are looking at x-max as an indicator of "slam". That probably is not a good indicator, alone.

What slam really is, is difficult to define. I'll hazard a guess that it arises from an optimally dampted system which requires a consideration of the small signal T-S parameters (Vas, Fs, and Qts) of the woofer and the design of the ported box (mass of air in the port and box size spring) are matched to each other in calculations.

From what I read, a woofer with a Qts (always close to Qes) of 0.4 is optimal for ported boxes. If you look at woofers at Parts Express, many have that spec. The modern K-33 too. Many of the T-S alignments wind up describing the same box / port size when you crank in Qts = 0.4.

The effect of damping is somewhat difficult to describe. Suffice to say that we want the combination of woofer and box to let the diaphragm move with the minimal amount of damping which gets in the way. Too little damping allows the diaphragm to resonate -- and we get booming because of peak in a freq.. You hear cars with this on the street booming away with a sub.

Too much damping prevents the diaphragm from moving in an amount which is desired. This results in essentially lack of low freq extension.

So, where does this damping come from? It describes something like putting a finger on the diaphragm to keep it from moving.

We have to realize the duality of the electrical motor of the woofer (or any dynamic speaker). It is a coil of wire in an magnetic field fed by an electrical source (amplifier). So, the stronger the magnet and the more windings of wire, the stronger the motor. But it also means it is a strong generator. If you have a strong hand operated generator it is harder to crank when under load. In the case of the woofer - as a generator - it is loaded by the output circuit of the amplifier. Modern amps have a low output impedance, or almost a dead short.

The above is a complicated. But it describes that we can get into trouble with lower than optimal Qes woofers because the electrical system acts as a finger on the tuning fork, More so than is optimal. We want the diaphragm to move.

- - - -

Getting back to the original subject.

It seems to me you mostly looking at x-max in the hunt for good performance. Or, question low x-max. The real solution is to consider all the T-S parameters.

I’m not educated in the simulators which are out there on the web. Perhaps someone here can step up and make a suggestion. My guess is that you’ll find that the modern K-33 (as a driver) and Cornwall (as a box and port) are very close to optimal for a box with a volume of about six cubic feet.

WMcD.

[geoff.]

sticky

[pzannucci]

19 hours ago, geoff. said:

sticky

Why?

[geoff.]

There is a LOT of good information I stumble across in these archives and I don’t always remember where to look later.

 

I was also on a device that would not allow me to “follow” the thread.

 

Easy fix is a post, check posts when I get home, and follow... if I remember.