Crossover Roadshow

[The Dude]

Jeff good to see ya on here posting, seems to rarely happen these days.[]

[Cut-Throat]

Dean,

You had mentioned that you preferred PIO in Type 'A's for SET amps. What PIOs do you like these Days?

Still Jensens ?

[Deang]

Jensen is the only current production PIO I've heard. I preferred the Type A with the Apollos, but that doesn't mean that's what everyone else is going to prefer with their particular set up. For example, Bruce likes the DHA2 and Super AA, while Jay prefers the ALK (he also uses the 45).

[Marvel]

Just to float this back to the top... I've been a bit more critical of my own setup since I had the Super AAs in my system. I think I want to make some adjustments with my tweeters, but not sure how to go about it, so some crossover help would be great here.

Since I had drop my mids a little when I built my DHA2 crossovers, the mids are all better and it makes the bass seem a lot batter. But, always a but... after listening to the Super AAs, I realize my tweets are a little too hot. I could really tell compared to the SAA crossovers, since I have a 1st order on the tweeter. A lot more info gets through. How can I easily get the gain down on my CT125s? Maybe only 1.5-2 db.

And, Nick should be getting the cossovers today, they are out on the delivery truck now. [] Unless they sit there until Tuesday... []

Bruce

[The Dude]

Yes I received them today got to love saturday delivert, how long are most spending with these before Dean starts charing rental feed.

[Marvel]

I think I actually had them a couple of weeks or longer. I just hadn't had time to give a good listen. I really enjoyed having them in my system. I may be the only one not buying a pair, but we're trying to sell our house and move... blah, blah, blah, so our funds are tight once again. (I could just strip down those battery biased ones and be done with it for the second set of LS I have).

Bruce

[Marvel]

Nick -- Inquiring minds want to know what you think about the crossovers. I really enjoyed having them in my system for a while.

Bruce

[The Dude]

Nick -- Inquiring minds want to know what you think about the crossovers. I really enjoyed having them in my system for a while.

Bruce

Well let me first disclose that the only thing I have to compare it to was a pair of a/4500 networks from Bob. Now I think when I was running that system I was using the Altec 511b horn with the K55v driver, and I think that is what I was having problems with. But with a couple of different horns, and these networks I know I am probably losing some low mids do to the type of horn. But from the listening I have done the last 2 weekends it sounds very good. I hear good detail from my system, bass seems more pronounced then before, the Highs are a little crisp but I think Dean even recommended a l pad to attenuate the tweeter. I still have more experimenting to do with my system, but if I was looking for a network upgrade in a pair of stock Klipschorns this would be the way to do. It amazes me how good these can make all the wrong things sound so good(if that makes any since).I don't know if my statements are helpful but I try. Bottom line I don't want to send them back.

[Deang]

Dean,

I did read that.

Let me sum that up. You said that Dennis said:

"Adding the swamping resistor cannot alter the acoustic loading the driver sees (which causes the distortion to peak when the impedance peaks too), but it does allow the crossover to work much better."

I guess this means that if you had a horn mouth reflection that occurs at the crossover point, you might see changes in the slope. And that the swamping resistor would damp them.

Do we have any of those?

I don't know what happened to Dennis. Maybe he's just tired of talking about this topic. I mean, you can only say the same thing so many times before you just throw your hands up.

http://forum.speakerplans.com/16ohm-hf_topic74463_page1.html

In your hypothetical problem -- aberrations in the amplitude response caused by the impedance peaks should be reduced. A swamping resistor is just one way of dealing with the problem. I'm sure you're familiar with conjugate networks, which are widely used in many fine sounding loudspeakers including the Jubilee and modern version of the Klipschorn and LaScala. I don't see what all the fuss is about, at least we still use an autoformer. So there is one resistor, big deal. The proof is in the sound, and so far it is has been preferred by every single person who has audtioned it. There has been one exception, and that person preferred the sound of the Type AA with Jensen paper in oil capacitors, and we all know how terrible those are.

With so many trying different horns and drivers, the ability to attenuate is a useful feature, and so far, "the tradeoff" seems more imagined than real. In fact, it would seem the use of a swamping resistor really does help.

"The fairly resonant decay signatures are typical of PA-style horns, and are caused by standing-waves reflecting from the sharp edge of the horn-mouth reflecting back into the horn and hitting the phase plug. The standing-waves are also responsible for the characteristic triple-peak seen in the impedance curves of most horns - which makes passive crossover design considerably more challenging for horns, thanks to the impedance variations."

http://www.nutshellhifi.com/MLS/MLS3.html

"You see that the value of mouth impedance will dictate the value of the throat impedance. As explained previously, there will usually be reflections at the mouth, and depending on the phase and magnitude of the reflected wave, it may increase or decrease the throat impedance. A horn with strong reflections will have large variations in throat impedance. Reflections also imply standing waves and resonance. To avoid this, it is important to terminate the horn correctly, so that reflections are minimized."

https://www.grc.com/acoustics/an-introduction-to-horn-theory.pdf

"Optional component (Rs) is a shunt resistor placed across the driver to swamp impedance peaks, where required."

http://www.pispeakers.com/Pi_Speakers_Info.pdf

At the resonance frequency of 37 Hertz, Lowther driver have a large peak in impedance. This occurs in the same range that many output transformers see a peak in their reactance. The combined effect causes poor power transfer to the speakers because the impedance is too high. Often a high quality 50 ohm resistor in parallel with the drive may lower the speaker impedance in the resonance range sufficiently to allow better power transfer. I suggest you use a Mills non-inductive wire wound resistor.

http://www.lowther-america.com/tweaks.htm

[John Warren]

Here's my take on the so-called swamping resistor......http://www.northreadingeng.com/Forums/index.php/topic,45.0.html

[The Dude]

Why would one want to lower the output, as in less dbs on the mid horn. Hopefully that makes since. Would doing this make the bass or highs more predominant. I know each is their own but for me I love the mid section. I am at the lowest tap settings 0 and 1 I believe when I raise this which I will tomorrow, will it let more of the other be more predominant. I understand what Dean is saying about adding the swamp resistor(in Layman's terms in a since, I guess it makes since to me anywho). I think impedance matching is important for the simple fact that the anything will take the path of lease resistance. That last sentence prob. doesn't make since but it sounds good to me.

[Deang]

Why would one want to lower the output, as in less dbs on the mid horn.

To many, the midrange sounds too forward, especially when played loud. The loudspeaker is only perfectly balanced in an anechoic chamber with a microphone acting as "the ears". Once you slide the loudspeakers into the room, the room exacts its influence and the microphone from the chamber is replaced with real ears -- and no two are the same. We also have the Equal Loudness Contours to consider as well as our gear and source material. In the HT world, it's common to use something like Audyessy or some other program to equalize the output for a more even response. On the fly attenuation is simply a tool that is used to rebalance the output due to the aforementioned factors (not to mention the use of different horns and drivers).

Would doing this make the bass or highs more predominant.

If you lower the midrange output, the bass and treble will move perceptually forward. No one says you have to attenuate more, if you like midrange, simply attenuate less.

I am at the lowest tap settings 0 and 1 ..

You are at what I would call the default or starting point for the big drivers, which is -12dB (or 12dB or attenuation) -- it is not the lowest setting, which is -22.7dB!

- / + dB

------- ----

X – 1 -22.7

1 – 2 -19.7

2 – 3 -16.7

0 – x -15.0

3 – 4 -13.7

0 – 1 -12.0 (starting point for drivers with 2" exit/ BMS, B&C, Radian, etc.)

---------------------------------------------------------------------------------------------------------------

X – 3 -9.8

0 – 2 -9.0

1 – 4 -6.8

0 – 3 -6.0 (preferred by many who listen louder than most)

X – 4 -5.5 (default setting using Al's Trachorn or Dave's Fastrac)

2 – 5 -3.8 (my preferred default setting for stock Klipsch components)

0 – 4 -3.0 (Klipsch stock setting)

Within reason, what sounds right is right. Remember, we all have different rooms, different gear, and more importantly -- different hearing curves.

[BEC]

I wonder how many of those who "fixed" the sound by turning down the midrange really had a phase reversal on the woofers. I know that several I have talked to who initallly wanted to know how to lower the midrange output, got happy with the factory balance once they got the woofers in phase.

[Deang]

I used to own AK-4 Klipschorns which I tore down and modified. I replaced the K-401s with Al's Trachorn, and replaced the K-55-Xs with JBL 2470s. Most around here know that I went through a pretty long list of amps and preamps, and since I could build my own networks, I had quite a few of those too -- including the Universal Type A (ALK) and Super AAs. I went through a period where I was playing things pretty loud, especially when I had the Bryston 3B-ST and Aragon 4004 MKII. I used the Universal with those amps because they were best suited for high SPL listening.

After being told that the swamping resistors were probably robbing my amplifier of close to half their rated output (something I actually partially agreed with at that point in time), and that the power rating of the resistor was undersized (10 watts) -- I decided to see how hot I could get the resistor. The amplifier was the Aragon 4004 MKII and I used Rush Moving Pictures. The system was hitting peaks of 120dB, and after the first few minutes I left the room. I listened to the rest of the CD while sitting at a chair in the dining room downstairs -- still uncomfortably loud. After the CD ended, I went upstairs, and turned my left Klipschorn away from the wall. Because of the math that some had been tossing around, I expected the resistor to be scorching hot, so I was a little careful when I went to touch it. Imagine my surprise when the thing was only slightly warm to the touch.

I didn't fully trust what Al had been telling me, but the lack of heat seemed to support what he had been telling me. I traded emails with Gil (even cornered him at the first Klipsch Pilgrimage in Indy to talk about the issue), Dennis, and Max Potter (former engineer at Klipsch) to try and get a better understanding of the impact of this single resistor. After my real world experience and the discussions I decided the detractors were wrong and quit worrying about it.

The "twenty seven eight-by-ten color glossy photographs with circles and arrows and a paragraph on the back of each one explaining what each one means" are pretty impressive -- but something isn't right. A resistor that should get hot, doesn't. And filters that supposedly prevent motors from doing what motors want to do sound as good or better than filters that supposedly do. It's not my intention to demean John's work, which is always impressive -- but in this case, something just isn't right with it.

[Deang]

I keep contact with two people who are using 45 SET amps. They have 1.5 watts. They report room filling sound with no issues. I don't see how that's possible with ANY crossover using that type of amp, but that's what they're reporting.

[Deang]

Well, I have limitations and I've never been shy about admitting them. When someone says my amplifier power is cut in half and that my 10 watt resistors are going to go up in smoke -- I know an easy way to test that theory

[Deang]

When you had the Belles and my crossovers, what did you power them with? BTW, both of those crossovers were constant impedance designs -- did you ever run into a power problem? I remember you didn't like the first order version (you thought the tweeter was too hot), but liked the second, which was the same as the crossover the people in this thread are trying out.

[BEC]

I was able to get Al's swamping resistor pretty hot during a test I did for him and Dave using the Eliptrax horn and HF200 driver crossed at 400hz to see if the combination worked good enough to use in a Khorn. I used about 100 watts into the crossover for about an hour. I think it woud be a matter of what the music content is. For instance, one might try big band sound and that with all that midrange content might just cook the resistor after a time. And, for those who like to listen to 1khz test tones, on a Khorn, I think that by the time you got to about 113db out of the Khorn midrange, you would cook the resistor.

[The Dude]

Bob what all of Als or what were the details of the crossover network did you use and what were your thoughts on in.

[BEC]

And, for those who like to listen to 1khz test tones, on a Khorn, I think that by the time you got to about 113db out of the Khorn midrange, you would cook the resistor.

Sure, that makes sense.

I used about 100 watts into the crossover for about an hour.

PLaying music? Do you mean 100W peaking on an amplifier meter?

I mean the equivalent to 100 watts average as measured in voltage at the input to the crossover. See, we were trying to prove that the Faital HF200 driver could take the amount of power it could see used in a Khorn.