Horn Speakers - Is it me or.......

[HiMu]

The driver (s) above the midwoofer-which is apparently 98db https://soundbox.co.jp/GPA/Classic-Series-416-8B-Spec-Sheet.pdf -will likely at least 10db more sensitive. So, to reduce my fears, it's obviously absurd looking for some 0.5 wpc amp to drive the compression driver (s).

As an example only, here is the schematic of L-pad in Scott Hinson's multiple entry horn for B&C464 16ohm coaxial compression driver (sensitivity ~112-113dB), according to his paper this produces 18dB attenuation.

 

[olegtern]

Why would you want to use them together?

Which one would least alter the impedance seen by the amplifier and driver?

If you get autoformer with e.g. max. -12db attenuation and need more - you can pair them. L-pad alter impedance, autoformer can increase distortions, no free lunch.

5-10 W amplifier for CD - another solution, but not without own flaws))

Or do they add distortion?

If they not good or used wrong.

Presumably if you're listening to something unpleasantly loud you'll turn it off really quickly

Or just use two of your fingers to plug the ears, and your feet to turn off the amp

 

[Newman]

but I can't get past this however much irrational (?) fear that these >>97db SPL drivers-through component failure, software glitch or user error-might get their dedicated amplifier's full power fed to them and permanently damage my hearing.

The difference between 97DB and 87DB speakers is only 10 DB. If your amplifier accidentally putting full power through 97DB speakers will damage your hearing before you can reach the Off switch, then having 87DB speakers is unlikely to really save you either! I think that a degree of realism versus risk is in order here.

 

[dped90]

If you get autoformer with e.g. max. -12db attenuation and need more - you can pair them. L-pad alter impedance, autoformer can increase distortions, no free lunch.

I haven't yet settled on a driver for above the midwoofers, but here's the impedance curve for those.

https://cdn.shopify.com/s/files/1/0142/2848/8292/files/Altec_416-8B_100L_Sealed_480x480.png?v=1695410822

But you're saying that there's no passive attenuation scheme that could produce inaudible impedance changes or distortion levels?

If your amplifier accidentally putting full power through 97DB speakers will damage your hearing before you can reach the Off switch, then having 87DB speakers as unlikely to really save you either! I think that a degree of realism versus risk is in order here.

 

[Newman]

But you're saying that there's no passive attenuation scheme that could produce inaudible impedance changes or distortion levels?

A simple resistor divider between pre and power amps will do it.

 

[Bjorn]

The JBL 2384 looses vertical directivity quite high in frequency. It makes it only a mediocre horn and with typical frequency deviations in the listening position. I have tested it.

 

[olegtern]

But you're saying that there's no passive attenuation scheme that could produce inaudible impedance changes or distortion levels?

I did not say that, please don't "quote" in that manner..

In both cases, we are talking about barely audible changes (when used correctly). A huge number of passive horn speakers have been using these solutions, and everything works great.

 

[Andysu]

still no issues with professional cinema , professional Dolby reference standards with professional commercial lucasfilm ltd THX sound system with JBL hf horns
mono , Dolby Stereo 3 screen Dolby Stereo 5 screen , Dolby Atmos 22.1/2/4/6/8 .20 ( customised beyond )


x5 JBL 2445J , x5 2380A
behringer EPQ amplifier more than enough HF cinematic dynamic range of real reference home cinema THX
THX cinema fully treated absorbed walls ceiling so no echo short reflections pinging HF sounds , just direct sound from those location positions , no honky sound ( often heard with short dialog pulse sounds or effects music if know how to monitor it ? ) that i often hear in most high end home theatres ( no honky sound be allowed here ) just the soundtrack only

 

[dped90]

A simple resistor divider between pre and power amps will do it.

Right, from the multichannel DAC's outputs.

 

[dped90]

The JBL 2384 looses vertical directivity quite high in frequency. It makes it only a mediocre horn and with typical frequency deviations in the listening position. I have tested it.

I haven’t seen sonograms on the JBL 2384, but if x& y coverage only starts to appreciably narrow above ~ 13kHz then I have no worries. It’s also clear that Mitch Barnett has long not been a fan of beamy waveguides. https://www.audiosciencereview.com/...ds/horn-speakers-is-it-me-or.9633/post-260352 , and during that year the JBL 4722-which uses the JBL 2384 horn-were his home speakers, though he apparently concedes that the newer M2 is better, at least in some respects.

Horn Speakers - Is it me or.......

OK, it happened again. I recently listened to some large horn speakers. I have periodically done this over many years at various hifi shows. I came away again with the same thoughts. I just don't get them. Firstly they were clearly highly directional. Unless I was right bang in the firing...

www.audiosciencereview.com

And that would be great because I forgot how big the 2384 horn is; hardly a practical fit for my ~ 2 ft w x 1.5” d midwoofers. Hopefully, a horn with that footprint ,like the M2, will be best choice.

 

[dped90]

I did not say that, please don't "quote" in that manner..

In both cases, we are talking about barely audible changes (when used correctly). A huge number of passive horn speakers have been using these solutions, and everything works great.

Sorry about that, but I should have known that I would be able to avoid any impedance changes from L-pads and distortion from autoformers by getting the needed hardwired attention simply by using a purely resistive voltage divider, as Newman suggested, yes?

 

[Flaesh]

p.s.:

this is Da-pad attenuator, named after the Armenian letter "Da"

 

[babadono]

A voltage divider is a "fixed" L Pad attenuator. In practice a store bought speaker L Pad usually has two moving wipers that keep the impedance seen by the amplifier at some nominal value. i.e. 8 ohms for hooking up to an 8 ohm speaker.

 

[dped90]

A voltage divider is a "fixed" L Pad attenuator. In practice a store bought speaker L Pad usually has two moving wipers that keep the impedance seen by the amplifier at some nominal value. i.e. 8 ohms for hooking up to an 8 ohm speaker.

Why would there be more than one wiper for use between the speaker and amplifier output?

In any case, use of passive attenuators requires compensate for insertion loss. https://www.electronics-tutorials.ws/attenuators/attenuator.html

Therefore, for my purpose as explained above, it is better to design the L Pad to be used between the output of the DAC and the power amp or between the amplifier and speaker driver?

 

[Cogito]

I've yet to hear a horn system that "wowed" me, and all that I've heard (Almost all Klipsch and one JBL) have all sounded "shouty" to some extent.

 

[Duke]

Why would there be more than one wiper for use between the speaker and amplifier output?

babadono pretty much described why:

A voltage divider is a "fixed" L Pad attenuator. In practice a store bought speaker L Pad usually has two moving wipers that keep the impedance seen by the amplifier at some nominal value. i.e. 8 ohms for hooking up to an 8 ohm speaker. [emphasis Duke's]

What happens is this:

One wiper varies the resistance in series with the driver, and simultaneously the other wiper varies the resistance in parallel with the driver, in such a way that the driver's nominal impedance is preserved regardless of how much the L-pad is attenuating the signal going to the driver.

So if you have an 8-ohm driver that you wish to attenuate, you'd use an "8 ohm" L-pad, and the impedance of driver + L-pad would stay pretty close to that nominal 8-ohm value regardless of where on the dial the L-pad was set to.

 

[dped90]

So if you have an 8-ohm driver that you wish to attenuate, you'd use an "8 ohm" L-pad, and the impedance of driver + L-pad would stay pretty close to that nominal 8-ohm value regardless of where on the dial the L-pad was set to.

Thanks for this explanation. The whole point of my inquiry into the use of attenuators was due to my personal fears about connecting high efficiency drivers directly to even relatively low wpc power amps when using active crossovers; see last section of post 974.

So, to minimize both risk of hearing damage accidents and minimize sound quality losses, is it better to design the L Pads to be used between the outputs of a DAC like this https://www.merging.com/products/interfaces/hapi

Merging Technologies | Horus & Hapi Mic-Pre & AD/DA Converter Specifications

Horus & Hapi mic preamp and ADDA converter has some of the best specifications of any I/O on the market today. Have a look at the numbers here.

www.merging.com

and the power amp or between the amplifiers and speaker drivers?

 

[Duke]

Thanks for this explanation. The whole point of my inquiry into the use of attenuators was due to my personal fears about connecting high efficiency drivers directly to even relatively low wpc power amps when using active crossovers; see last section of post 974.

So, to minimize both risk of hearing damage accidents and minimize sound quality losses, is it better to design the L Pads to be used between the outputs of a DAC like this https://www.merging.com/products/interfaces/hapi

Merging Technologies | Horus & Hapi Mic-Pre & AD/DA Converter Specifications

Horus & Hapi mic preamp and ADDA converter has some of the best specifications of any I/O on the market today. Have a look at the numbers here.

www.merging.com

and the power amp or between the amplifiers and speaker drivers?

I would put the L-pad between amplifier and speaker drivers, mostly because that's what I'm familiar with. If someone with experience using L-pads further up the signal chain tells you otherwise, follow their advice over mine.

If you decide to go with an L-pad between amp and speaker drivers, you could do this: Buy an inexpensive L-pad and use that to dial in the correct loudness for your horn, then disconnect the L-pad and measure the series resistance and the parallel resistance, and then you would know what values you want for the (presumably) fairly expensive resistors for your permanent, fixed-value L-pads.

If these are clones are they just as good as the JBL originals? https://reconingspeakers.com/product/jbl-m2-horn-lens-5025594/

I don't think that's a clone. I think that's the real deal. I think you can see one in action here:

M2!5 Loudspeaker – PBN Audio

pbnaudio.com

I like the way Peter Noerbaeck mounted the horn upside-down to slightly decrease the center-to-center spacing between horn and upper woofer.
https://reconingspeakers.com/product/jbl-m2-horn-lens-5025594/

4.) While best achieving accurate imaging, what aspects of this waveguide may cause errors in the sound? For example, if the waveguide narrows too much towards the HF band, resulting in a very limited horizontal and/or vertical sweet spot even when listening within the critical distance. Of course, while I am looking for constant directivity, thus absolutely NOT looking for any kind of omnidirectional sound, I would hope to be able to stand and without moving beyond a ~ 4 ft radius not lose any appreciable x & y coverage.

Imo for good imaging across an area, not just right smack in the sweet spot, you want the off-axis curves to be essentially less-loud-replicas-of the on-axis curve, as this will give you the option of using time/intensity trading to get good imaging across the listening area.

Four feet is not a very wide listening area, so imo you don't need a really wide constant-directivity pattern. The off-axis curves of the 18Sound XT1464 track the on-axis curves exceptionally well across an arc 60 degrees wide from 1 kHz to about 11 kHz, and it's still pretty good south of 1 kHz and north of 11 kHz.

5.) Or if sharp edges inside the waveguide or around the mouth cause resonances or diffraction effects, respectively, how to fix them?

It's not really possible to "fix" that kind of acoustic problem with EQ. The signal still gets diffracted. EQ can make a significant improvement at one microphone location but at different locations the equalization will not be correct.

Please don't tell me that if I want to go with the best waveguide for my situation that I must also use active crossovers to apply that eq accurately enough to avoid audible problems.

I've been using waveguides & waveguide-style horns that are constant directivity (or nearly so) for about twenty years and imo passive crossovers work just fine. But if you're going to be doing the crossover yourself, active crossovers are a lot more user-friendly.

 

[mhardy6647]

The driver (s) above the midwoofer-which is apparently 98db https://soundbox.co.jp/GPA/Classic-Series-416-8B-Spec-Sheet.pdf -will likely at least 10db more sensitive. So, to reduce my fears, it's obviously absurd looking for some 0.5 wpc amp to drive the compression driver (s).

Yeah, I agree! But 750 mW... Bob Daneliak's "Darling" amplifier (single-ended 1626 outputs) should do the trick!

see, e.g., https://evilscienceaudio.com/2013/11/03/single-ended-1626-darling-amplifier/

 

[MAB]

Thanks for this explanation. The whole point of my inquiry into the use of attenuators was due to my personal fears about connecting high efficiency drivers directly to even relatively low wpc power amps when using active crossovers; see last section of post 974.

So, to minimize both risk of hearing damage accidents and minimize sound quality losses, is it better to design the L Pads to be used between the outputs of a DAC like this https://www.merging.com/products/interfaces/hapi

Merging Technologies | Horus & Hapi Mic-Pre & AD/DA Converter Specifications

Horus & Hapi mic preamp and ADDA converter has some of the best specifications of any I/O on the market today. Have a look at the numbers here.

www.merging.com

and the power amp or between the amplifiers and speaker drivers?

I use an L-Pad to stabilize Compression Driver's impedance. Like this:

I can't understand how limiting the signal at the DAC prevents hearing or driver damage compared to limiting at the driver. And the L-Pad at the driver reduces hiss, the filter capacitor reduces it even more, and also blocks DC in case you actually have a problem. I have very low noise amps, but could use just about any amp with the L-pad and not hear hiss.

My tweeter amp is very powerful, I don't worry about losing my hearing from some accident. I worry about damaging my hearing from listening to loud sounds for extended periods of time, for example public transportation which is surprisingly loud. If you are worried about damaging your ears while fussing with your amps and drivers, wear hearing protection. Or turn the amp off while you are messing around. Otherwise the speakers will be fine as long as you don't abuse them.

If these are clones are they just as good as the JBL originals? https://reconingspeakers.com/product/jbl-m2-horn-lens-5025594/

They are the real thing. You can build a pair of JBL M2 for cheap, have some of the best sounding speakers available, if you like them.