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New BEC Tweeters


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My K77M fell off just as Bob's plot shows but not as fast. Of note: I couldn't hear anything after 15K Hz.

-jwcullison

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JC,

Did you mean you couldn't hear anything from both tweeters after 15khz due to your hearing (ears)?

If so, and you never had any obvious trauma to your hearing (accidents), I wonder how many of us over 30 are able to hear past 15 khz, and how much does our hearing "slide" with age? Could it be that by a certain age, our upper-range of hearing (15-20khz) is pretty much shot?

-H2G

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I couldn't hear any over 15000Hz for both tweeters. I don't have the best hearing. I am thirty six years old. I've had my hearing checked several times actually...now don't laugh but there is a 9000Hz drop in my right ear vs my left. I can blame my father for this....too many shotguns blasts as a kid.

Besides the 9000Hz dip, my hearing objectively is fine. Subjectively, however, there must be something wrong...everytime I play some quality music such as Jazz, classic rock, etc, I end up later crankin some "Korn" or "Disturbed"

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15 is my limit -- and I can just barely make it out. I'm 47.

It's not just how far a tweeter goes out though, but how it actually sounds from where it starts it work to where you can't hear anymore. Once again, things that often measure close to the same don't always present themselves acoustically anywhere near the same way. This tweeter thing is a good example, as well as the Trachorn/K-401. Look at Bob's plot, and compare the FR and output to where you know you can't hear anymore. So, what explains the "big improvement"? Go to Al's site and look at the Trachorn/K-401/511B plot -- the lines are all over on top of each other -- but the sound is oh so very different!

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15 is my limit -- and I can just barely make it out. I'm 47.

It's not just how far a tweeter goes out though, but how it actually sounds from where it starts it work to where you can't hear anymore. Once again, things that often measure close to the same don't always present themselves acoustically anywhere near the same way. This tweeter thing is a good example, as well as the Trachorn/K-401. Look at Bob's plot, and compare the FR and output to where you know you can't hear anymore. So, what explains the "big improvement"? Go to Al's site and look at the Trachorn/K-401/511B plot -- the lines are all over on top of each other -- but the sound is oh so very different!

Very true! Measurements only get you so far...amazing how somthing so similar on paper can sound so different in "real life."

I'm pushing 34, and I don't think my ears are what they used to be!

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"...to my ears, the BEC tweeter beat the sound of the Beyma..."

"...Being more musical than the Beyma..."

"What I hear that is better than the Beyma is more realism reproducing the sounds of cymbal strikes..."

The Beyma doesn't sound near as good with a first order tweeter filter as it does with a third order. I tried like heck to make it work with a single cap but no matter what cap I used or where I shifted things around it always sounded a bit splashy and dry. The driver really takes on a different character in the AA, SAA, and ALK -- very airy and smooth which works great with the crap I listen to.:)

"...Since this tweeter is good down to 3500 hz, I have modified my type A crossover to lower the K55/tweeter cross to 4500 hz..."

Phenolics definitely behave very nicely with the first order filters.

The last time I spoke with Bob about his mod he wasn't completely set at to how he was going to handle the tweeter section -- what did you guys finally decide on?

"Klipsch had already figured out that the K-55 is beyond it's best behavior when it naturally poops out at 6000hz and changed the AK-4 crossover to this 4500 crossover."

It actually starts to poop out well before that, but there is a peak around 5kHz or so and when it's mated to the K-401 the response is lifted and it goes out to about 6kHz. There is nothing revelatory here -- Klipsch has known this for a heck of a long time, and several here have known it for just as long. Now you know why PK wanted a driver that went out to 6kHz -- hence the K-55-V with the dual phasing plug and K-55-M. And yes, this also explains the lowering of the crossover point with the new networks -- since the K-55-X is a single port phase plug design (like the old K-55-V with spring loaded terminals).

"This crossover mod should not be attempted using a K77 tweeter. (unless you just want to need a new K77 diaphragm) Klipsch is able to accomplish this 4500hz crossover in the AK-4 with a sixth order extreme slope filter (or some such thing as DeanG explains way over my head) without damaging the K77. Anyway, it works great with the BEC tweeter because it will handle staggering levels of signal."

Yes, 4500Hz works with the new networks because they have offloaded a substantial amount of energy from the K-77-F with a 36dB/octave filter.

"I had no idea that I was hearing distortion from the K55, until I wasn't hearing it any more. Trey was explaining to me about Klipsch discovering that and making the change in the AK-4 crossover."

Arg, this is annoying (C'mon Trey!) I sure hope he didn't make this sound like they just figured this out three years ago when they went back to the Atlas driver! At any rate, most of the distortion is from the horn, not the driver. More on this later, I have to go pick Debbie up from work.

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I wonder how many of us over 30 are

able to hear past 15 khz, and how much does our hearing "slide" with

age? Could it be that by a certain age, our upper-range of hearing

(15-20khz) is pretty much shot?

It's pretty average... 15 to 16Khz for someone between 25 to

35... women usually do a hair better. If i recall

correctly, I tested at about 15800hz... and my girlfriend out did me by

about 100Hz.

20Khz really is for newborns and dogs... but if we put it in

perspective, we are talking less than 1/2 an octave difference between

15khz to 20khz

ROb

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Does this mean that the current AK-4 networks and speaker (woofer, squaker and tweeter) sound better than earlier networks and speaker selections?

Bill

My take on it, is that the AK4 network would result in a smoother midrange and transition to the tweeter.
That's my take on it, too, based on my switch to the AK-4.
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I am sorry for being an idiot with this but smoother with Bob's new tweeter or the one from Klipsch???

Bill

Bill.

Smoother is a tough one for me to place with audio.....unless I was from New York or New Jersey and think its "like butter".

I think Bob's tweeter will beat the K77 in just about any category. Better power handling, lower crossover point. The way it sounds is a subjective thing and you would just have to hear it. I thought it sounded great.

The fact that it extends out to 20Hz looks good to me on a paper.

I have yet to hear from those who have previously demoed this tweeter to say there is any disadvantage of the CT-125 vs K77.

I say again. There is no reason to buy a used K77 off Ebay anymore. For the price of Bob's tweeter, you can't beat it.

jc

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...okay but what I am confused about is the BEC tweeter a mod for ALL K'Horns and similar speakers or is it fixing a problem of the older networks solved by Klipsch with the AK-4 network??? I have the AK-4 network (most current) and all new tweeters, squakers and woofers...will I get improvement with Bob's new Tweets or ...see my question??? I guess I am not emplaining myself well and for that I apologize.

Bill

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You might want to shoot Trey an email and see if he would be willing to forward it to Roy Delgado. The AK-4 is a pretty busy network, and there's something in each part of the network that addresses the "peculiararities" of each driver and/or horn. IOW's, it's completely optimized for those particular drivers and horns. However, you might get lucky.

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I'm sorry. I understand your question.

I couldn't give you a certain opinion with a tweeter replacement with your current network. There is no doubt in my mind that the K77 with a first order network will scream at you with higher volumes. The CT-125 won't do that ...I bet.

Now I have demoed the K77 and the CT 125 on a third order tweeter filter...the ALK B. The K77 sounds nice and wasn't as "tingy". Infact sounds good even at loud volumes. To be honest...and I mean really honest...I didn't notice a huge jump in difference when using Bob's tweeter with the ALK B. I do think his tweeter is better.

I unfortunately didn't try it with a first order when I had it. I regret that because I bet it would sound great just as my JBL 2404 does with first order.

So again...my statements have been consistent in saying that there is no reason why you would want to buy a K77 when there is the CT 125 coming. However, I can't give you a confident answer that swapping out a perfectly good K77 with a CT 125 will make a "big" improvement with your AK-4 (higher order tweeter filter). If you are a first order network guy...I bet you will notice a difference easily.

Bob. Have you done any comparison between the two tweeters with anything other than first order filters?

jc

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Bill,

Don't worry, sensing confusion after reading one of my posts is par for the course.

Two different issues here. The first is that the BEC tweeter is a drop in replacement for any K77 and a huge improvement, IMO.

Second, if one desires to modify a type A (or AA I suppose) network to take advantage of the BEC tweeter's range and power handling capacity, it is easily done. This crossover mod has the advantage of narrowing the bandwidth of the K55, which makes for the smoother mid-tweeter transition.

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"This crossover mod has the advantage of narrowing the bandwidth of the K55, which makes for the smoother mid-tweeter transition."

Because you've lowered the crossover point -- yes -- but it also lowers distortion emanating from the throat of the horn.

Bob -- I've got to ask this: Whatever happened to allowing the driver/horn to determine the cut-off? Why drop the crossover point? Now you're stuck with putting that resistor, uh -- I mean inductor into the network.:)

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