Handmade Ersatz M9500 Speakers

[Mr. Widget]

I have built and used a couple of different Tractrix horns, on JBL 2426 and TAD2002 drivers, and found that they sounded very good, however I needed to aim them correctly, and sit within the high frequency “sweet spot” to get the full treble experience. They also worked better in over damped (Live-end Dead-end) rooms. (quite bad with wood floors and bare walls/ceilings.).

I agree... I listen in a treated room. Since I enjoy stereo, I listen primarily in the sweet spot. My current speakers have a slightly wider sweet spot than tractrix horns have, but you absolutely need to sit in the zone to get the full benefit.

With the Oblate Spheroid horns, I get excellent frequency response regardless of what position I take in the room,...

For me off axis listening is just casual background entertainment and having an acceptable but less than perfect presentation there is more than adequate. As stated above, for stereo listening you have to be in the sweet spot anyway so optimum performance outside of that envelope is just not worth compromising the performance in the sweet spot.


Widget

[Robh3606]

I can stand, or sit, and even walk across the entire width of the room, barely 3 feet in front of the speakers (or at the back of the room), and I hear *exactly* the same frequency response (and high frequency extension) as I would in my sweet spot favorite listening position.

I could never do that with my tractricx horns.

Hmmm

I had a similar impression when listening to them as well. I like to have good balance through out the room as well.

Rob

[jack_bouska]

For me off axis listening is just casual background entertainment and having an acceptable but less than perfect presentation there is more than adequate. As stated above, for stereo listening you have to be in the sweet spot anyway so optimum performance outside of that envelope is just not worth compromising the performance in the sweet spot.


Widget

It's not that I need to listen while walking around, or that I need to satisfy a widely dispersed audience, its just that I listen to the direct arrival, the early reflections, *and* the reverberant (decaying) sound field when I sit in the sweet spot.

I still think good CD is important for quality sound reproduction. Good CD means flat, ripple free (and internal reflection free) on and off axis response. The attached graphic (from JBL literature) explains it better than 1000 words from me.

Jack Bouska

[Mr. Widget]

It's not that I need to listen while walking around, or that I need to satisfy a widely dispersed audience, its just that I listen to the direct arrival, the early reflections, *and* the reverberant (decaying) sound field when I sit in the sweet spot.

I still think good CD is important for quality sound reproduction. Good CD means flat, ripple free (and internal reflection free) on and off axis response. The attached graphic (from JBL literature) explains it better 1000 words from me.

Oh, I understand the concept, and it really makes sense. However in my own real world experience, the systems that I have really responded to, the ones that really sounded the best with stellar imaging etc. are not examples of controlled directivity. I think that in the PA world JBL is right, but so far, in domestic Hi-Fi listening, I still need to be convinced.


Widget

[Robh3606]

Hello Widget

You like the Revels?? They are CD like as far as there in room response in concerned. More controled directivity but very similar. The power response rolls off a bit but it is very much along the same lines. Smooth curves with no sharp of abrupt changes. They are designed using the same guide lines as the 6300 series Monitors as far as On and Off Axis response.

http://www.jblpro.com/LSR/PDF/JBL.tn_v3_2A.pdf

Rob

[Ian Mackenzie]

Jack,

Correct me if I am wrong but what you are talking about is the sound quality of the horn itself . Issues of driver loading, throat impediance, the horn contour and mouth termination all seem to play a role in the subjective performance whereas there are numerous biradial CD horns that have technically good dispersion but are not subjectively that great.

I read the above links, very informative.Thankyou.

Ian

[Robh3606]

Hello Jack

I have a question about both the Peavey horn and Earls. In both cases the measurements stop at 10K. What actually going on above that frequency?? The 2344 used the difraction slot width to determine the HF beamwidth limit in the horizontal plane. Both Earls horn and the Peavey don't have this feature so the smallest dimension is the throat diameter. In Earls I think it's a 1" throat while the Peavey is 1.6". Are the throat dimensions acting as a difration slot as far as the upper limit dispersion in concerned. Does the directivity change above 10K???

Rob

[Mr. Widget]

Hello Widget

You like the Revels?? They are CD like as far as there first reflection. The power response rolls off a bit but it is very much along the same lines. Smooth curves that are similar with no sharp of abrupt changes. They are designed using the same guide lines as the 6300 series Monitors as far as On and Off Axis response.

Interestingly, I do like them though I am not all that crazy about the LSRs, but I don't think it has to do with their dispersion characteristics... they simply sound a bit hard at anything above easy listening levels. I know the Revel has a similar wave guide around the tweeter, but I am not sure if it would actually be considered CD. CD, like minimum diffraction designs, time aligned designs, and other previous flavors of the month may not be all that important in and of themselves... what I mean is that I have heard loudspeakers from virtually every major design theme that have sounded great... no single concept seems to be critical, though I am sure each of the various proponents would violently disagree me... it is just that if time alignment is so critical, then how can a completely screwed up system from this perspective sound fantastic? If minimum diffraction is so....

In any event, all of the CD designs that I was thinking of were horn designs, and when thinking of horn based systems, the systems that have sounded the best have never been constant directivity systems. I have heard excellent wide dispersion systems and excellent narrow dispersion systems, but those described as CD have never been even close to the best in the other categories... that may change with the advent of newer designs and technologies.


Widget

[grumpy]

In any event, all of the CD designs that I was thinking of were horn designs, and within that family of designs, the systems that have sounded the best have never been constant directivity systems.

You lost me there. I thought CD = constant directivity? -grumpy

[Mr. Widget]

You lost me there. I thought CD = constant directivity? -grumpy

I am using CD to mean constant directivity. Where did I lose you? I rewrote the quoted line... maybe it makes more sense now?


Widget

[grumpy]

Thanks Widget,

Requote did the trick. Not being picky intentionally... this is a useful thread of information and
experience and I want to make sure I understand the intent. Clear enough now. -grumpy

[Zilch]

It's not that I need to listen while walking around, or that I need to satisfy a widely dispersed audience, its just that I listen to the direct arrival, the early reflections, *and* the reverberant (decaying) sound field when I sit in the sweet spot.

I'm not so keen on early reflections as I once was, particularly those coming from the floor and ceiling. The ambience is nice, but it's artificial. 90° x 50° is my preferred pattern, of late, with toe-in to reduce early reflections from the front sides.

None of this diminishes the importance of uniform power response for the reverberant field, tho. Like you, it's not my desire or objective to create an "oversize headphone" listening experience, but I don't think a symmetrical dispersion pattern is the ticket, either. I particularly enjoy the H2600/H3100 asymmetric pattern.

Widget HATES it. There's no sweet spot, which is disconcerting.

[Well, there IS, but you gotta measure to find it. Tee hee.... ]

[Robh3606]

I particularly enjoy the H2600/H3100 asymmetric pattern.

Widget HATES it. There's no sweet spot, which is disconcerting.

Hello Zilch

Now that's a horse of a different color. That's a DC horn or Defined Coverage as JBL called them based on the 4660.

http://www.lansingheritage.org/html/.../1984-4660.htm

I would very much like to hear what they sound like.

Rob

[Mr. Widget]

Hello Zilch

Now that's a horse of a different color. That's a DC horn or Defined Coverage as JBL called them based on the 4660.

http://www.lansingheritage.org/html/.../1984-4660.htm

I would very much like to hear what they sound like.

"Widget hates them" is over stating it... I wouldn't pick them out to be a horn that I used on a daily basis, I certainly can see the appeal... They absolutely give a very unique stereo sound stage. If we ever have the time, it might be interesting to try out the TAD 2002 drivers on them... these drivers are supposedly good to 27KHz... I take all of these specs with a few grains of salt. One of my issues with most of the two-way designs is the quite audible distortion up top that is only aggravated by combining them with horns that have a falling off on axis response.


Widget

[Zilch]

If we ever have the time, it might be interesting to try out the TAD 2002 drivers on them....

Well, sure, we'll have the time. When the new throats get here, we can hook a pair up!

I could send some off to Rob to hear, as well, then.

[The horns, not the TADS.... ]

One of my issues with most of the two-way designs is the quite audible distortion up top that is only aggravated by combining them with horns that have a falling off on axis response.

I believe you will find 2452H-SL on 2352 very different in these respects.

Not bad on the PT Waveguide it was designed for, either, which is on topic, since Jack cited PT-H95HF above....