Why Do Big Ole Heritage Horns Cut Off At 17kHz?

[tube fanatic]

We "old timers" who have been in the tube amp design field for 50 or more years have long realized that a practical design goal is a flat frequency response between 35-40 Hz and 13-15 kHz! Extending beyond that range is usually inaudible to most listeners and adds greatly to the cost of the required output transformers. Some may disagree with this philosophy, but my experience has demonstrated its validity. Good luck with your quest though!

Maynard

[artto]

Do yourself a favor and go see an ear doctor/audiologist and get a hearing test. They'll print out a chart for both your ear's response and how your hearing compares with the general popluation for your age. That will put to rest what you can or cannot hear in the upper frequencies. Anything else will be just pure fantasy on your part. If you still think you can hear something up there beyond what the hearing test shows you'll have to look elsewhere for what is causing your "tweeter experience". [D]

[merkin]

The last that I could hear was the 12 hz and had to have the volumne way up. I could not hear it until I turned off TV. Maybe if I waited until my refrigerator stopped running I might have heard higher but I doubt it. I don't hear my coffee pot finished signal unless I'm right next to it. My kids yell at me all the time that my coffee is done.

[JJkizak]

Do you mean 12 KHZ?

JJK

[bracurrie]

Because most of the audible information is from the midrange, I would not rule out the midrange driver, horn, and or the crossover.

I agree. The more work and attention I pay to the highly audible mid range and crossover area the more I seem to get out of the higher frequency range. While my hearing doesn't extend beyond 17khz or so it appears that there are some harmonics in the audible range that are affected by having both the midrange sorted out and the super audible clean. Nothing worse that MP3 where the high end is mangled, as it makes listening long term annoying.

[DavidF]

Is it strictly limitation of the tweeter, or does it have to do with overall integration/synergy with the rest of the system; is the tweeter response held back intentionally? What can be done to achieve more extension on the top end of the Klipschorn? My 56 year old ears are in pretty good shape so I am missing quite a bit of top end.

Rick

The horn tweeter is starting to beam above about 8,000 Hz or so. Meaning that the off axis response is falling off faster than directly on axis. This is going on with the mid horn as well. The amount of high frequency energy bouncing off the walls, etc. is therefore less and this makes the overall power response droop depending on your exact listening position. The fix sometimes used is a form of equalization in the passive xover to allow the tweeter response to rise a bit at frequencies above 8-12,000 Hz. Though this helps in the overall power response it can sound harsh and piercing on axis with the drivers.

The EV unit used by Klipsch actually performed better in the horizontal plane when the long axis of the horn was up and down. Could be that the horizontal orientation used by Klipsch better blended with the mid horn response so that is why they chose to keep both horns horizontal.

[garyrc]

When I was in my thirties I discovered, quite by accident, that I could hear 16K through a T35 (aka Klipsch K77, used in Klipschorns) from directly behind the speaker (in a room that was fairly live). Now, I have to be absolutely on axis to hear 12.5K. Yet ... music still sounds crisp and shimmering when playing many SACDs, CDs, BDs, etc. My audiologist measures at threshold, which may miss any possible effect on high frequency hearing of the CNS arousal that accompanies loud passages in music, or sudden or dramatic changes in SPL. Cymbal crashes sound like they always have, to me, but very soft conversations sometimes lack their old clarity, which is too bad, because I love to eavesdrop.

According to Belton, in Widescreen Cinema, the 6 channel magnetic soundtracks used with 70 mm Todd-AO (late 1950s & 60s) rolled off at 12K, but my audiophile friends and I considered them to be much higher fidelity than anything we heard in the audio stores of the time. We didn't notice any roll-off with our then teenaged ears compared to what we heard in the orchestra most of us played in.

The EV unit used by Klipsch actually performed better in the horizontal plane when the long axis of the horn was up and down. Could be that the horizontal orientation used by Klipsch better blended with the mid horn response so that is why they chose to keep both horns horizontal.

If I remember one of the T35 spec sheets correctly, the frequency range in which the tweeter had better response when placed vertically was toward the bottom of the T35 range, rather than toward the top.

[garyrc]

When I was in my thirties I discovered, quite by accident, that I could hear 16K through a T35 (aka Klipsch K77, used in Klipschorns) from directly behind the speaker (in a room that was fairly live). Now, I have to be absolutely on axis to hear 12.5K. Yet ... music still sounds crisp and shimmering when playing many SACDs, CDs, BDs, etc. My audiologist measures at threshold, which may miss any possible effect on high frequency hearing of the CNS arousal that accompanies loud passages in music, or sudden or dramatic changes in SPL. Cymbal crashes sound like they always have, to me, but very soft conversations sometimes lack their old clarity, which is too bad, because I love to eavesdrop.



According to Belton, in Widescreen Cinema, the 6 channel magnetic soundtracks used with 70 mm Todd-AO (late 1950s & 60s) rolled off at 12K, but my audiophile friends and I considered them to be much higher fidelity than anything we heard in the audio stores of the time. We didn't notice any roll-off with our then teenaged ears compared to what we heard in the orchestra most of us played in.



If I remember one of the T35 spec sheets correctly, the frequency range in which the tweeter had better response when placed vertically was toward the bottom of the T35 range, rather than toward the top.

[JL Sargent]

My son (see avatar) and I took an online hearing test. I was saddened to realize I had lost it beyond approx 13K. While my son could hear the tones clear up to 20K. I know I can comfortably go two way now on my speakers now. [:S]

[Audible Nectar]

It is the limitation of the stock tweeters used in the Heritage line that is the limiting factor in the high frequency response.

I don't consider this to be an issue though - in fact I like them that way. Especially the early round magnet AlNiCo versions - soft and sweet sounding - not too offending on anything less than perfect in terms of recordings.

Yes, the use of top flight tweeters (like you see here in modded versions) will improve the high frequency response - more air, but more of the imperfections of the recording, too. When I made the decision to keep my tweeters original, it was a conscious decision, because I like the "forgiveness" and the overall sound of those tweeters. Even in one set having V-Cap networks and amps with teflon caps, those tweets stay sweet....and the benefits of tube rolling still remain in spades.

I appreciate the modded versions in some respects, but I find that setting up my systems for that "uber-revealing" quality limits my choice of recordings too much. I listen to a breadth of material and have found my systems to be preferable for my tastes with the old round magnet K77s. I hear the aftermarket tweeters TOO well.

It's great for the budget, too - no need for me to spend beyond the stock form. PWK did a lot right here.

[JJkizak]

On your online hearing test which speakers were used? Were they computer speakers or the main Klipsch system? It might be more accurate to use a frequency test DVD in your system.

JJK