JBL Array 1400 - cabinets are live!

[dcolak]

If you find them harsh at high level that might have more to do with HF than LF and cabinet vibration.

The directivity pattern of a horn speaker, and especially the array, is very different from a cone speaker. As it is constant direcititvy you get much more overall HF in your power response.

Look at these measurements:

Array 1400:
http://www.audioheritage.org/vbullet...1&d=1156648272

PT800 Perforcamne (certainly simiular to your klipch speaker in term of direcitivty pattern)
http://www.audioheritage.org/vbullet...1&d=1157034351

Pay a close attention to the total power response (4th curve from top, the lowest of the top curves). You see that it tends to drop with frequency on conventional cone speakers, whereas it remains much flatter with the array.
This is what constant direcitivty brings you, but it can be a problem if your room is live, especially at high levels and when you are far away from the speakers, because what you hear then is mostly the power response.
If that is the case you have two options: treat your room with some good dampening (and possibly more sophisicated treatments), or use some EQ to lower the HF level during parties.

I think you're onto something. That makes perfect sense.

Klipsch RF-83 probably did roll-off a bit over 16Khz which made their horns more listenable at high levels.

A bit of EQ at the top might make all the difference with the Arrays

[timc]

How many W RMS did you feed them with? I am really interested in knowing that information, it puts things into perspective.

If you used 30-40W RMS we are not talking about the same thing.

It was a Crest PA amplifier with 300Wpc 8ohm. We played as loud as we felt the array could handle. The woofer did really move, and i was just waiting for the large windows to shatter. This was a conventional A/B design but i think it was PWM power supply. Not the most refined and detailed sound, but rock solid fundament and not harsh in any way.

BTW: Most class D i have heard (mainly based on B&O ICE or Tripath), sounds restrained and quite harsh in the treble. Same goes for Class I (Crown I-tech)

[timc]

Klipsch RF-83 probably did roll-off a bit over 16Khz which made their horns more listenable at high levels.

I measured a RF-63, and it showed a huge dip in the upper midrange. It was quite wide as well. Then it came full force from 8-9Khz, with a rize towards 20KHz. No rolloff. On-axis mind you.

After some research we came to the conclusion that the dip was the result of the inevitable diffraction cancellation you get from "flat mouthed square/circular) horn mouths. Ref. Geddes paper on sound radiation from circular apperatures from 1993 (AES)

[dcolak]

I measured a RF-63, and it showed a huge dip in the upper midrange. It was quite wide as well. Then it came full force from 8-9Khz, with a rize towards 20KHz. No rolloff. On-axis mind you.

After some research we came to the conclusion that the dip was the result of the inevitable diffraction cancellation you get from "flat mouthed square/circular) horn mouths. Ref. Geddes paper on sound radiation from circular apperatures from 1993 (AES)

Interesting. So what's cutting our ears might not be the 14Khz+ but the 6-10Khz range.

Compared to Array 1400, Klipsch RF83 sounded dull and attenuated in high frequencies.

[dcolak]

It was a Crest PA amplifier with 300Wpc 8ohm. We played as loud as we felt the array could handle. The woofer did really move, and i was just waiting for the large windows to shatter. This was a conventional A/B design but i think it was PWM power supply. Not the most refined and detailed sound, but rock solid fundament and not harsh in any way.

BTW: Most class D i have heard (mainly based on B&O ICE or Tripath), sounds restrained and quite harsh in the treble. Same goes for Class I (Crown I-tech)

Which model of Crest did you use? How much attenuation did you select on the dials? What was the input V?

Using a pro amp with -dB dials makes it easy to know exactly how much W you are sending into the speakers

As I understand it, Yamaha uses proprietary "D class a-like system" EEEngine.

EEEngine

EEEngine (Energy Efficient Engine) Technology makes more efficient use of AC power by reducing power consumption and heat generation without sacrificing output power or sound quality. When power requirements are low, the system uses a highly efficient current buffer to transparently switch input power on and off as needed. As power requirements increase, an independently responding auxiliary power line supplies additional power as required. Output isn't compromised because the auxiliary power line is driven by the power supply voltage which maintains maximum output to the speaker load.

[timc]

Interesting. So what's cutting our ears might not be the 14Khz+ but the 6-10Khz range.

As you probably have guessed i find the Klipsch way harsher than the Array ( i worked at a Klipsch dealer for 5 years). My believe is that the dip in the Klipsch means, that the upper harmonics is relatively unaturaly strong compared to the lower harmonics. There at not many fundamentals in the 5-7K range. This making the sound a bit clinical and "analytical"

When it comes to what is annoying, personally i really hate excessive "sssss" sounds. This sound is 8-10KHz.

[rdgrimes]

Listening fatigue with speakers of this caliber points to poor placement, poor room treatments and/or an amp that's clipping. Could be all 3. Based on the photos, room treatments are certainly needed. Most people would be reaching to turn the Arrays UP, not down, presuming proper setup. That front wall alone is a source for many bad reflections, and they should be pulled out as far as possible away from it even with treatments. But no amount of electronics fiddling, EQ or the like will make a bad room better.

[timc]

Which model of Crest did you use? How much attenuation did you select on the dials? What was the input V?

Using a pro amp with -dB dials makes it easy to know exactly how much W you are sending into the speakers

I have not idea of this. It was not my system. I THINK the dials were at max. We used a ARC LS2B linestage.

[dcolak]

As you probably have guessed i find the Klipsch way harsher than the Array ( i worked at a Klipsch dealer for 5 years). My believe is that the dip in the Klipsch means, that the upper harmonics is relatively unaturaly strong compared to the lower harmonics. There at not many fundamentals in the 5-7K range. This making the sound a bit clinical and "analytical"

When it comes to what is annoying, personally i really hate excessive "sssss" sounds. This sound is 8-10KHz.

That's exactly how I would describe Array 1400 sound! The excessive "sssss" sounds!

The Klipsch RF-83 sounds mellow, compared to Array's.

[timc]

That's exactly how I would describe Array 1400 sound! The excessive "sssss" sounds!

Then my conclusion is that you have a relativly high reverberation time in your room at thoose frequencies. And that the wider vertical dispersion of the Array horn makes it worse. Try putting something porus on the ceiling and floor.

Also makes sure that you are not confusing the SSSSS sound with the SCH sound. The SCH is located in the 1-3KHz range.

[dcolak]

Listening fatigue with speakers of this caliber points to poor placement, poor room treatments and/or an amp that's clipping. Could be all 3. Based on the photos, room treatments are certainly needed. Most people would be reaching to turn the Arrays UP, not down, presuming proper setup. That front wall alone is a source for many bad reflections, and they should be pulled out as far as possible away from it even with treatments. But no amount of electronics fiddling, EQ or the like will make a bad room better.

We measured Klipsch RF-83 frequency response at the place I'm sitting at and there were no big dips or hills in it.

One of these days I should measure the Arrays.

No amp clipping with 500W RMS and dial set at -20 dB or -10 dB

[hjames]

That's exactly how I would describe Array 1400 sound! The excessive "sssss" sounds!

The Klipsch RF-83 sounds mellow, compared to Array's.

Could it be that the Klipsch doesn't reproduce that sssssssssss band as accurately, so when you get a speaker that does - you can hear the amp's noise better, and are blaming the speaker on it?

[pos]

Klipsch RF-83 probably did roll-off a bit over 16Khz which made their horns more listenable at high levels.

The interesting curve is the power response one (4th curve from top, the blue one one the array measurement), not the on-axis response.
The > 15khz response should not be a real problem. It is more in the 5khz-15khz range that things happen.

You could try a gentle shelf filter above 5khz, slowly reducing gain up to something like -6dB at 20khz (~-3dB/oct).
But that would only be a quick fix to get that mellow sound your party mates were accustomed to.
The real fix would be to treat your room.

[timc]

We measured Klipsch RF-83 frequency response at the place I'm sitting at and there were no big dips or hills in it.

As I said, I would asume that the dip dissapears a few degrees off axis. I did not double check this. The analysis we did is only valid On-Axis. But it could explain the power response dip that Pos is showing.

[pos]

some explanation on the axial vs power reponse can be found here, page 2:
http://www.jblpro.com/catalog/suppor...=303&doctype=3

The Array 1400 is a constant directivity loudspeaker, whereas the Klipch is not (a horn does not guaranty constant directivity).