Anyone know the efficiency Rating of the Khorn Bass Bin ?

[Cut-Throat]

Khorns themselves are rated at 104db. But I have an Altec Midrange and Driver that is rated at 109db.

So I was curious what the Bass Bin sensitivity rating was.

[The Dude]

I would like to know as well, glad you asked.

[Quiet_Hollow]

From a factory brochure.

[Cut-Throat]

From a factory brochure.

Yes, This rating is for the entire speaker. I wanted to know the sensitivity of just the Bass Bin.

[Deang]

Yes, that's what plots looks like after the marketing folks see what the real ones look like.

Attached is a plot of the unfiltered response comparing the Klipschorn and the Jubilee bass bins. The Klipschorn has a large peak, and with the older networks which incorporate the single 2.54mH inductor for the low pass -- the peak remains. The peak is 107dB.

The early AK series of networks begin to deal with this, the AK-4 and AK-5 networks completely kill it offering a very smooth response. John Warren's KS1 and KS2 also do a nice job of smoothing thing out. http://www.northreadingeng.com/Klipschorn_net.html

I bought AK-4 Klipschorns back in 2005 I think. I discovered that I liked the peak -- nice kick drum slam and superior transients. Towards the end I even removed the low pass coils and ran them babies full out. My networks had three parts. Well, five if you count the boards and barrier strips.

Pay me enough and I'll risk banishment by posting the complete in-network responses, in the chamber, without smoothing. I always think: how can something that looks so bad sound so good? :-)

khjub.pdf

[psg]

How do you measure a corner speaker without measuring the room response needed for it?

[Islander]

How do you measure a corner speaker without measuring the room response needed for it?

Good point, and a great example of YMMV.

Somebody posted a year or two ago about having Khorns in a room with stiffer-than-usual walls and mentioned how the bass was a bit better than you usually hear with those speakers.

[Deang]

He asked about the sensitivity of the bass horn. The room gain from corner loading is factored in since the Klipschorn is actually in a corner when it's loaded into the chamber. Also, I was once told that Klipsch assumes corner loading for the great majority of their products and adds 4dB to their sensitivity specifications.

[LarryC]

I thought I remembered reading decades ago that K-horn efficiency dropped from 50% in the bass to about 10% in the treble, and averaged 30% for the whole thing. I have no idea where I read that or how authoritative it was. Maybe Dope from Hope?

[The Dude]

If I understand this correctly when you say peak you mean the last dip before it rolls off completely. Since it stays above 107db through out, then it would be 107db efficient up to about 450-500hz.

[Islander]

He asked about the sensitivity of the bass horn. The room gain from corner loading is factored in since the Klipschorn is actually in a corner when it's loaded into the chamber. Also, I was once told that Klipsch assumes corner loading for the great majority of their products and adds 4dB to their sensitivity specifications.

I could believe that. When I replaced my old bass reflex speakers with La Scalas, I expected about a 10-14 dB increase in sensitivity, but my measurements indicated more like 8 dB. Neither speakers were near a corner, but had the same wall about a foot behind them in both cases.

Either my old speakers were around 96 dB sensitive, which seemed optimistic, or the La Scalas were closer to 100 dB. I didn't think I had the gear or setting to make absolute measurements, but the relative measurements should have been sufficiently accurate. The same testing method and equipment gave me consistent results when comparing Heresy II to Heresy III (2 dB up for H3, the same as Klipsch specs), so I have confidence in them.

[djk]

No = 10% = 102dB/W/1M

So what is the Klipschorn?

And what is the Jubilee?

[The Dude]

Where would one want to place a mic if they wanted to test the bass bin in room frequency response, or efficienc.

[Arkytype]

After replacing the original K-33 woofers in my 1979 Klipschorns with a pair of Bob Crites' CW1526C cast frame woofers, I did a before and after measurement of one of the bass bins.

A 1/2" Bruel & Kjaer 4133 microphone was placed at the left mouth centered on an imaginary line drawn from the front panel to the wall. I was surprised to see a huge (13.5 dB) increase at about 24 Hz compared to the K-33! Measurement of both Klipschorns confirmed the unexpected LF boost.

If you want an accurate measurement of your loudspeaker's low frequency performance try using Don Keele's ground-breaking (in 1979) technique of placing the microphone capsule a fraction of an inch from the woofer's dust cap. his paper can be found at:

http://www.xlrtechs.com/dbkeele.com/PDF/Keele%20(1974-04%20AES%20Published)%20-%20Nearfield%20Paper.pdf

[Islander]

After replacing the original K-33 woofers in my 1979 Klipschorns with a pair of Bob Crites' CW1526C cast frame woofers, I did a before and after measurement of one of the bass bins.

A 1/2" Bruel & Kjaer 4133 microphone was placed at the left mouth centered on an imaginary line drawn from the front panel to the wall. I was surprised to see a huge (13.5 dB) increase at about 24 Hz compared to the K-33! Measurement of both Klipschorns confirmed the unexpected LF boost.

That's pretty impressive. Was it as obvious to your ears as it is to the eyes?

That makes me want to buy cast frame woofers for all my Scalas, except the dimensions of the La Scala bass horn might not cause/permit a low bass boost like that. It would be great if it did, but I've never seen any comments to that effect from the number of people who have installed those woofers in their LSes.

[Arkytype]

Islander,

According to Bob's website, the cast frame CW1526 will not fit in the La Scala; the stamped frame will. Since the Fc of the La Scala is higher than that of the Klipschorn, I don't know if there would be much usable output in those nether regions.

I've not explored the spectrum below the nominal Fc of the Klipschorn before, but plan to do some extensive distortion vs. output testing in the 20-40 Hz range. As for the audible difference between stock and replacement woofers; I'd want to restore one of the Klipschorn bass bins woofers and do some measurement/listening tests.

Lee

[o0O Bill O0o]

I use (guessed) 97dB with my active crossover as I had to drop the level of the mid/hf horn by almost 9dB. (I also assessed the mid/hf horn to be 106dB)

I used the AudioAudit app on my iPhone for the SPL to determine the SPL with a 1Khz tone and a 200Hz Tone for the HF/MID and Bass horn , respectively.

I need to refine my practices, as I did a rough assessment, there is room to get better!

[Islander]

Islander, According to Bob's website, the cast frame CW1526 will not fit in the La Scala; the stamped frame will. Since the Fc of the La Scala is higher than that of the Klipschorn, I don't know if there would be much usable output in those nether regions. I've not explored the spectrum below the nominal Fc of the Klipschorn before, but plan to do some extensive distortion vs. output testing in the 20-40 Hz range. As for the audible difference between stock and replacement woofers; I'd want to restore one of the Klipschorn bass bins woofers and do some measurement/listening tests. Lee

The CW1526 will not just slip into place, but can be made to fit, either by grinding away some material on opposite sides of the frame, or by cutting reliefs in the inside edges of the La Scala doghouse. That sounds extreme, but a few forum members have done those things and posted pictures of them.

However, as you mention, the horn itself would likely be the limiting factor. People that have installed the cast frame woofers like the sound, but nobody has said it changes the La Scala into a bass monster.

[Islander]

He asked about the sensitivity of the bass horn. The room gain from corner loading is factored in since the Klipschorn is actually in a corner when it's loaded into the chamber. Also, I was once told that Klipsch assumes corner loading for the great majority of their products and adds 4dB to their sensitivity specifications.

I looked through my Pictures folder and found this ad for the La Scala Industrial which shows the sensitivity figures under free space conditions at a distance of three meters to be 96 dB with 1 Watt and 119 dB with 200 Watts input.

That would indicate that the sensitivity would be over 100 dB in free space at 1 metre (current spelling), and of course it would be higher in a corner.