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View Full Version : Where to mount the075/077?



jblwolf
04-18-2003, 08:02 AM
Greetings,
glad to see everythings up and running,Ive been working on mounting my 2390 horns on top of my cabinets for some time now and I'm at the point that I need some input for the forum,please see picture--I guess my question is,should I mount the 075/077 under the 2390 or mount it on top of the 2390

Robh3606
04-18-2003, 09:56 AM
Well I would look at the height from the floor as a major consideration. The 2405 is very beamy in the vertical axis so I would mount it as close to ear level as I could. You can go either way. Most of the large format monitors had it next to the midrange horn. The 4333 was above and the Classic Audio Reproduction speakers the Westlake monitors the new 4368 all have it bellow the horn at ear level.

Rob:)

Mr. Widget
04-18-2003, 10:43 AM
I agree with Rob, you want it near ear level, if this isn't possible you can angle it upward or downward toward your expected listening location. Secondarily I would be concerned with the cabinet or mid lens causing early reflections. This can be reduced by using some type of sound absorbing material.

Finally, yes the 077/2405 is beamy vertically, but the 075/2402 is beamy in both axes.

4313B
04-18-2003, 01:56 PM
Well.... I prefer the 2405 pointed directly away from the listener, firing into the fiberglass lined loudspeaker enclosure. It's a courtesy thing...

Now the 077 looks too damn cool to mistreat in such a manner. That baby needs to be up front and center and at eye/ear level; just leave the wires leading to it unhooked ;)

ROFLOL!

Mr. Widget
04-18-2003, 02:02 PM
OK Junior Member, don't forget your medication.:D

scott fitlin
04-18-2003, 02:07 PM
Viagra here, get your red hot Viagras here! Good for when you listen to vintage audio. :D

jblwolf
04-18-2003, 04:09 PM
if I mount the 075/077 under the horn it would be ear level-seated-

Mr. Widget
04-18-2003, 04:21 PM
That should work out well then.

If it is very close to the mid lens but mounted on the plane of the front of the horn and rear of the lens, I would be concerned about the highs bouncing off the underside of the lens.

I noticed that you have referred to the use of an 075/077. Are you planning on using both for a comparison?

Ian Mackenzie
04-18-2003, 04:59 PM
Heres a good example that worked well

Thats what you call WELL HUNG speaker, no viagra required
Ian

jblwolf
04-18-2003, 06:56 PM
Yes,I will be trying out both models,I also be trying out lx5-lx13-n7000-n8000 and rane ac23,I'm still working on the other channels(sub,rear,side)as well,at this point I could add both drivers at the top and bottom,but that maybe overkill,so I think I will just add the driver to the bottom of the horn and see how that sounds

4313B
04-18-2003, 07:03 PM
Well I am very interested to see what you end up preferring. What was the bass driver again?

Mr. Widget
04-18-2003, 07:20 PM
Yes, what is the driver compliment that you will be using.

I am not a big fan of the LX-5 N7/8000 vintage crossovers, you might consider building your own based on newer JBL pro designs. I have done this with great success. (With a little help from Giskard)

I was using the Rane AC 23 in my home theater, I am now using AC 22s for my three front channels. They are very flexible, but I don't think the circuitry is as open and free from a opamp grunge as I want in a dedicated two channel music system.

Don't get me wrong, music sounds fantastic through them, but just not as good as it can get.

scott fitlin
04-18-2003, 07:26 PM
Mr. widget, what your describing is something Ive experienced with all 24 db per octave filters! Its not open, sounds compressed as you push it. On the other hand, 18 db filters sound the opposite. very open and dimensional and free, at least more free, to my ears from grunge! rane gear in particular has that hashy mid.

Ian Mackenzie
04-18-2003, 07:57 PM
Guys,

Keep an eye on passdiy.com, Neslon Pass will be bring out a diy design active crossover soon called The High Low Pass, with discrete Jfet/bjt buffers.

This will no doubt be very transparent and the navana of bi amping.

There is a lot of debate on at the moment about the best topology for active crossovers, 4th order L/R on paper looks the best but not always the best sound according to some.

I found this design on diyaudio which apparently sounds very good

Ian

Ian Mackenzie
04-18-2003, 08:01 PM
The active discrete opamp will look something like this schematic,

I'll keep you informed about the pass project

Ian

jblwolf
04-18-2003, 09:49 PM
I will be using le15a's,my sub will use 2-2245's,the rear channels will use le14a's or le15's(I'm using 5.5 cuft cabs),375's (1237-1290)also mounted on top of the cabinet and 075 or 077,I always liked the stock x-overs,this will be the first time I used the ac23's,first on the agenda is getting the front channels up and running, using the passive x-overs.

Mr. Widget
04-18-2003, 10:37 PM
Thanks for the update Ian.

I have quite a bit of respect for Nelson Pass and his work. I am sure that what ever they put out will be technically excellent as well as actually good sounding and thoroughly listened to. So many designs are theoretically excellent and the designers believe in their theory more than their ears.

Scott, I have read your posts condemning 24dB slopes before. I am not sure if it is the slope or the design, but in the case of Rane I must agree I don't find Audio Nirvana in their crossovers. In my dedicated 2 channel setup I am using a 12dB Audioarts crossover. I like it's sound a heck of a lot more. When I first saw the ads for the new Pass Labs variable crossover, my first thought was GREAT- then I checked my checkbook. A Passdiy project would certainly be welcomed.

The problem with active crossovers is that they must be as good as your preamp or you will hear the signal degrade. Of course with passive crossovers there are all of the well known problems associated with them.

Kevin McDonald
04-18-2003, 10:55 PM
I'm probably goiung to cut the baffle tomorrow (nice hard maple stock) and I don't wanna do it twice.

Same beaming issue as the 2405's? I had been planning to mount them slightly higher than ear level, above the mid horn.

Mr. Widget
04-18-2003, 11:14 PM
I don't have personal experience with the 076s but on paper they are very similar to the 077/2405. I would bet they are the same.

As you probably have thought about, the further away your listening position the more off axis you can be. (In inches not degrees.)

4313B
04-19-2003, 04:22 AM
The 077/2405 is spec'd at 140 x 40 at 10 kHz. The 076/2403 is spec'd at 90 x 60 at 10 kHz. The 075/2402 is spec'd at 40 conical at 10 kHz. The 075/2402 is "good" to about 15 kHz and the 076/2403 and 077/2405 are "good" to about 20 kHz.

The direct radiators, such as the 066, are spec'd at 140 conical at 8 kHz and falling roughly 80 degrees per octave above 8 kHz. The 066 is "good" to 21 kHz and the 044Ti/046Ti are "good" to 27 kHz. If I remember correctly, the 033 is "good" to about 16 kHz and the 044 is "good" to about 18 kHz.

The direct radiators are significantly flatter in their response than the ring radiators at the expense of extreme SPL, but they are lower in distortion content as well. EQ and careful baffle placement can compensate for some of the "peaks" and "dips" experienced with the ring radiators. (I personally prefer using the 2504 bracket and forgoing baffles altogether unless mounting flush on the back wall in built-in applications) The design of the ring radiators hasn't really changed since their inception (with good reason, they're tough to beat) whereas JBL has continually tried to improve their direct radiators (also with good reason ;)). The addition of the 2404 was quite nice in rounding out the ring radiator family.

4313B
04-19-2003, 12:44 PM
"I will be using le15a's,my sub will use 2-2245's,the rear channels will use le14a's or le15's(I'm using 5.5 cuft cabs),375's (1237-1290)also mounted on top of the cabinet and 075 or 077,I always liked the stock x-overs,this will be the first time I used the ac23's,first on the agenda is getting the front channels up and running, using the passive x-overs."

You'll kill a pair of LE14A's in that large of an enclosure unless you tune them quite high or keep the power down, you might want to stick with the LE15A's instead. Are you using 075's because you have them or are you going to buy some? They'd be ok for surround I guess but I can't see using them for mains unless you have nothing else to use instead. If you're going to use 2245H subs I'd have to recommend looking at using the LE14A's/LE15A's in sealed enclosures to increase their transient response. Keep their Q in the 1/sqrt(2) to 1/sqrt(3) range.