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[Steve M Smith]

The above information is intended as historical information for those of us that appreciate the efforts of those who came before us.

Thanks for posting. I appreciate this type of thing.


If you were in the UK, I would recommend a visit here: http://chvintageaudio.com/


He has all sorts of stuff, including most of the WEM PA used at the 1970 Isle of Wight (where I live) Festival and a load of vintage Martin stuff.


The website is worth a look.




Steve.

[Luis_Marquez]

   The Sp2's you have there require CD horn eq in the horn section. This is in the passive crossover and if you Bi - Amp them you need to have the proper Constant Directivity Horn EQ applied.
   With a CD Horn Lens as the frequency Increases the Output decreases. This is a function of the horn Lens. ( the baby Butt ones in the sp2's you have and many other older peavey speakers )  So if you thought you were missing Highs when you Bi-amped them with the Peavey 22 ... drivers and didn't use proper CD horn eq then there was your problem.

https://peavey.com/content--name-Horn-Equalization

   The 22 drivers were good up to around 16khz or so. More than enough for an average bar band show they were meant to be used for.

Douglas R. Allen

I have read about this term” CD horn Eq” over the years but never dug into it. I read the Article and from my understanding, a pad or cut is applied to the mid/high section and a then a 6db/octave boost starting around 3-4khz. Can one apply this to a two or three way run passive full range? Would a characteristic of no CD horn eq result in harshness and/or beaming?

[Art Welter]

1)Can one apply this to a two or three way run passive full range?
2)Would a characteristic of no CD horn eq result in harshness and/or beaming?

1) Constant Directivity horn EQ can be implemented in passive or active crossover circuits.
2) A "Constant Directivity" horn by definition does not "beam", beaming is a progressive narrowing in pattern with increasing frequency. EQ does not affect the pattern control of a horn.
A CD horn without CD EQ sounds "dull", lacking high frequency.
Applying a CD EQ to a traditional exponential "beamy" horn would make it sound "harsh" on axis, as the beaming already compensates for the high frequency roll-off typical of HF compression drivers.

[Don T. Williams]

In reference to your question regarding the three EAW models, general a loudspeaker with a 2" throat (or more commonly now a 1.5" throat) horn can and will have a lower crossover frequency.  These "large format" drivers (typically 3" to 4" dia. diaphragms) will play louder and sound better with lower crossover frequencies that "small format" drivers (screw-on or 1" bolt on) with diaphragms as small as 1" diameter but more typically 1.3" to 2" diaphragms.  Often the "small format" driver will produce higher frequencies better (above 10-12KHz), but like everything, "it depends".  This will generally apply to the three choices you have selected from EAW.  Because you have a specific sound you prefer, you really need to actually listen too your choices.  Compairing sepcifications will never get what you desire.  I know that may be hard, but for you I don't think there is any other way to answer this question.  I'm not trying to push another brand on you, but RCF in its ART sereis has similar model 15" two way speakers with one small format and two large format driver models - ART 715A, 735A, and 745A.  These may be easier to find for demo than the EAW's.  Again, these won't sound exactly like the EAW's, but it might help you in your quest.  Every speaker has it's on sonic signature.

[Mike Henderson]

In reference to your question regarding the three EAW models, general a loudspeaker with a 2" throat (or more commonly now a 1.5" throat) horn can and will have a lower crossover frequency.  These "large format" drivers (typically 3" to 4" dia. diaphragms) will play louder and sound better with lower crossover frequencies that "small format" drivers (screw-on or 1" bolt on) with diaphragms as small as 1" diameter but more typically 1.3" to 2" diaphragms.  Often the "small format" driver will produce higher frequencies better (above 10-12KHz), but like everything, "it depends".  This will generally apply to the three choices you have selected from EAW.  Because you have a specific sound you prefer, you really need to actually listen too your choices.  Compairing sepcifications will never get what you desire.  I know that may be hard, but for you I don't think there is any other way to answer this question.  I'm not trying to push another brand on you, but RCF in its ART sereis has similar model 15" two way speakers with one small format and two large format driver models - ART 715A, 735A, and 745A.  These may be easier to find for demo than the EAW's.  Again, these won't sound exactly like the EAW's, but it might help you in your quest.  Every speaker has it's on sonic signature.

All great advice thanks! I was always leaning more towards the JF260 which is why it's first on the list and it's because of the 2" exit on the horn I gave it the edge. Just to clarify please does 2" "exit" mean it is a 2" driver and not the normal 1=3/8" driver?

[Douglas R. Allen]

All great advice thanks! I was always leaning more towards the JF260 which is why it's first on the list and it's because of the 2" exit on the horn I gave it the edge. Just to clarify please does 2" "exit" mean it is a 2" driver and not the normal 1=3/8" driver?

   There is the Horn Driver's Voice Coil size listed then there is the Horn Lens Throat Size often referred to as exit size. If you look down a horn toward the driver it gets smaller and smaller.  A 2 inch Exit horn means at its smallest point the horn lens opening is 2 inches and gets larger with the lens rate.
   *Part* of the "Compression" in a "Compression horn" is that its Horn Driver's voice coil is larger than the horns lenses exit size.  Often you may see a speaker listed as having a 1.4 inch compression driver when it has a 3 inch voice coil driver with a 1.4 inch exit horn. This as an example.

https://scontent-bos3-1.xx.fbcdn.net/v/t1.0-9/40912853_1949235521840761_1863240891284586496_o.jpg?_nc_cat=108&ccb=2&_nc_sid=730e14&_nc_ohc=tlTnWDzshzkAX_p4rHH&_nc_ht=scontent-bos3-1.xx&oh=851344ff9344554948e77c6c52007d03&oe=5FDFE2E8

   It's also possible to have a horn section with a 1.75 inch voice coil with a 1.4 inch exit horn lens.  It really depends. Its important to look at voice coil size in a horn as well as the exit size among other factors when looking at a horn system. 

   There is many here who excel in horn information and this is just a basic rundown. Others may chime in as well.

Douglas R. Allen

[Don T. Williams]

The "industry standard" screw on driver is 1 3/8th" 18 TPI screw size.  This is the oustide diameter of the mounting housing.  The actual throat is usually between 3/4" and 1".  The throat diameter is the size of the entry hole on the horn or wave guide.  These should be the same for the proper acoustic loading and smooth transition of the sound from the diaphragm to the horn/wave guide.  The diaphragm will usually be larger that that exit.  If you remove the diaphragm from the back of the Peavy 22 driver, you will see an aluminum or tiatanium dome that it is about 2" in diamether.  Attached to the dome is a voice-coil wound of copper or aluminum.  This allows the diaphragm to move back and forth in the voice-coil gap in the magnet structure.  You will see a phasing plug under the diaphragm.  Depending how old the driver is, it may have a lot of holes that angle to the driver throat or slots that taper into the throat.  The phasing plug "loads" the diaphragm acoustically and makes all areas of the diaphragm arrive at the same time in the throat of the driver.  If the phasing plug is removed, the driver output is greatly reduced and sounds bad.  The diaphragm diameter is usually about twice the diameter of the horn throat.

[Mike Henderson]

Got it, I think I have a much better grasp of this now, appreciate the help guys!

[ProSoundWeb Community]