PWK's Dope from Hope Speaker Placement Guide
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"After all, you couldn't hear the rest of the band if you had your head in the tuba."
I'm really, really sorry I never had the chance to meet him. He must have been a hoot. I do have his biography, and it's a great read.
I've read just a few of the "Dope from Hope" newsletters, and they're always informative as well as interesting.
Thanks for posting!
I'm really, really sorry I never had the chance to meet him. He must have been a hoot. I do have his biography, and it's a great read.
I've read just a few of the "Dope from Hope" newsletters, and they're always informative as well as interesting.
Thanks for posting!
pmsummer
simul justus et peccator
Thank you, sir. One never knows how long that Klipsch Date Code stuff will stay up on the original site.
Romak
Active Member
I found this awhile back. It talks about placement towards the bottom. I have my Fortes toed in just a few degrees and am happy, but may have to change after awhile to see.:scratch2: I would think the man who made these would know best..............
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October 1996..."Greg Smith"
If you've been reading my Entry Level columns, you've noticed that I frequently talk about my speakers. Klipsch introduced a collection of designs they called the Heritage series back around the beginning of the decade, and the jewel in that collection is a model called the Forte II. Being from Klipsch, they use horns, but these speakers are the best designed horns I've ever heard for any reasonable sum of money. They've been out of production for many years now, so I haven't been pushing them too much. Imagine my surprise when I found out that Klipsch is making them again, and they're even cheaper than before! With the current craze, centered around things like single ended tubes, toward higher efficiency speakers, it's particularly appropriate to talk now about what these speakers do well and to mention some of the things I've learned in five years of system matching.
The Return of the Forte II
Klipsch Forte II
$1000/pair. Horn Tweeter, Tractrix Horn Midrange, 12 inch woofer, 15 inch passive radiator, crossover points at 650hz and 7Khz. 99dB sensitivity, 8 ohm nominal impedance, 4 ohm minimum. -3dB@32hz, 20Khz.
There are speakers that you just buy, plug in, and play. Sure, maybe you move them around a bit, but most speakers aren’t all that difficult to get working well. These are not speakers like that. The Forte II is something you need to plan your whole system and room around to make it perform well. You don’t just pick a random set of components, position them like regular cone speakers, and expect them to perform. The result will probably sound horrible. I will fully agree that most horn design sound horrible in any case, including many from Klipsch. The Forte II can be made to sound very good, but it takes quite a bit of sweat. Just because you’ve heard horns before and thought they sounded bad, don’t dismiss these.
Here’s one thing I’ve noticed about horn speakers. Because the efficiency is so high, it’s much easier to use the drivers out of their normal operating range without causing over-excursion problems. This is why you’ll find so many two-way horn designs. You can push most tweeter horns so that they work down to around 2Khz, and keep the frequency response fairly flat. Unfortunately, this results in a less than pleasant off-axis response at higher frequencies. The horn problem most people refer to as "honking" is most obvious with two-way horn designs, and I’ve never liked them because of it.
When the engineers at Klipsch were designing the Tractrix midrange horn that is used in the Forte II, they found it could be used up to 20Khz if they played with the EQ on the driver. They didn’t do so; instead, there is a separate tweeter horn for the very high frequencies. Limiting the bandwidth used for the midrange horn lets it cover a horizontal area of 60 degrees smoothly while controlling the vertical coverage for better integration with the other drivers (see Tractrix Horns in the March 1991 issue of Audio for information how the Forte II was created). The fact that the midrange is so well designed is the primary reason this particular model sounds so much better than the other speakers I’ve heard from Klipsch, or from any other horn manufacturer for that matter.
The midrange is really what makes this speaker sound great. There’s a totally effortless feeling to vocals that comes from a driver operating nowhere near its limits in either frequency response or output level. And the foundation that midrange is working on is very solid. The bass is tight down to 30hz if the associated electronics keep up. You’ll feel little need for a subwoofer.
And if you want peak output, you’ve got it. I’ve measured my speakers clearing 115dB in my room before (with my ears covered, thank you). They sounded about as distorted as your average cone speakers do with 10dB less output (which is what you’d expect with a typical 10dB sensitivity difference). While I certainly don’t recommend listening to anything that loud, it’s nice to know you can use your speakers for low-grade sound reinforcement without constantly fearing damage. The low distortion makes the volume level deceptive; I can listen to these speakers at a considerably higher volume than more traditional designs without ear fatigue. Distortion makes speaker sound loud regardless of the volume, and it’s surprising how much quieter the same volume levels sounds without it present (this is a central concept to Paul Klipsch’s philosophy for the company).
Amplifier matching
With that 99dB sensitivity, you’d think you could use any old amplifier and have plenty of power. This is not at all the case. In order to match the output levels of the drivers (those horns are even louder than that without some padding), Klipsch uses some very unique matching techniques using things like a type of transformer. (see A Visit to the Klipsch Kingdom in the 4/89 issue of Speaker Builder for comments from Paul Klipsch on their autoformer design). Transformers are obviously inductive, as they are made out of inductors. What this means is that while the amplifier used doesn’t need to have a very high power output in typical terms, it does need to be able to deal with the very difficult load that inductors present. Using a cheap receiver to drive these speakers just because you don’t need much power is the wrong approach. What you need is a high- current amplifier that can deal with difficult loads without introducing problems.
One of the problems you’ll constantly fight with these speakers is that any components that might sound a bit harsh with other speakers will have that harshness revealed in all its glory. Use a typical cheap CD player and a pair of these speakers will drive you from the room. The amplifier matching in particular can introduce an incredibly rough sound. Back when I was using an Adcom GFA-555 with these speakers, an amplifier generally recognized as being a bit too aggressive in its treble, I had to deal with a level of sibilance that was almost unbearable. The Proton D1200 amplifier I current use is a very good match, but you can’t buy them anymore. Essentially, I recommend trying amplifiers from manufacturers known for producing laid-back components. I’ve had excellent luck building a system around these speakers with components from Rotel, and I have no reason to expect that their power amplifiers would be a bad match for these speakers (and they even make inexpensive, low-power models that still have excellent current driving ability). The tube amps I’ve tried all sound terrific with these speakers. A 35w/ch Dynaco ST-70 is plenty of power to drive a pair to ear-bleeding levels with no problems.
Placement
The other thing that really can bite you and leave a bad impression of these speakers is how you place them. All of Klipsch’s speakers are designed to be placed closer to the corners than typical designs. I like these best sitting about 1-2’ from the left, right, and rear walls. Pull them far out into the room and they don’t sound as good. Another things to watch out for is toe-in. Most people angle their speakers so that the drivers are directly facing them. Bad idea here--you want these facing directly forward, with no toe-in rotation toward the center. When pointed right at you, the harshness that’s always waiting around for the unwary comes right out. The off-axis sound is much smoother and more pleasant to listen to. The manual that comes with the speaker has very generic recommendations that recommend toe-in for all their speakers; ignore all of their suggestions. They may very well be true with other models, but with the Forte II they are just plain wrong (current production might have a revised manual that gives better advice).
Don’t wait too long...
Two warnings. First, if you’re interested, start moving now. I’m told that the rerelease of these speakers is a temporary thing, and that they are going to disappear again in some indeterminate period of time. Second, I haven’t actually had a chance to try out a sample from the current product run. I don’t see any design changes, and they seemed to sound about the same during a brief listen at the local dealer, but I’m not 100% certain these are exactly the same speakers I’m used to. Even if I had a pair, I couldn’t tell you for sure for a while--it took me six months to get my old pair broken in properly (you really have to move that woofer around to stretch the cone and radiator out to get the bass going as deep as it should). The bass does take a while before it sounds exactly right, and the volume level required to break these in right is enough to get your average dealer evicted if they tried it in the store.
As far as I’m concerned, the Forte II is a terrific design competitive with any speaker in the $1000 price class is every category. And they are possibly the best available in terms of deep bass output, sensitivity, and maximum output for that much cash. If you give them a fair audition, following the suggestions I gave for matching components and room placement, you may just find that inexpensive horn speakers can sound better than you thought possible.
.....GS
--------------------------------------------------------------------------------
October 1996..."Greg Smith"
If you've been reading my Entry Level columns, you've noticed that I frequently talk about my speakers. Klipsch introduced a collection of designs they called the Heritage series back around the beginning of the decade, and the jewel in that collection is a model called the Forte II. Being from Klipsch, they use horns, but these speakers are the best designed horns I've ever heard for any reasonable sum of money. They've been out of production for many years now, so I haven't been pushing them too much. Imagine my surprise when I found out that Klipsch is making them again, and they're even cheaper than before! With the current craze, centered around things like single ended tubes, toward higher efficiency speakers, it's particularly appropriate to talk now about what these speakers do well and to mention some of the things I've learned in five years of system matching.
The Return of the Forte II
Klipsch Forte II
$1000/pair. Horn Tweeter, Tractrix Horn Midrange, 12 inch woofer, 15 inch passive radiator, crossover points at 650hz and 7Khz. 99dB sensitivity, 8 ohm nominal impedance, 4 ohm minimum. -3dB@32hz, 20Khz.
There are speakers that you just buy, plug in, and play. Sure, maybe you move them around a bit, but most speakers aren’t all that difficult to get working well. These are not speakers like that. The Forte II is something you need to plan your whole system and room around to make it perform well. You don’t just pick a random set of components, position them like regular cone speakers, and expect them to perform. The result will probably sound horrible. I will fully agree that most horn design sound horrible in any case, including many from Klipsch. The Forte II can be made to sound very good, but it takes quite a bit of sweat. Just because you’ve heard horns before and thought they sounded bad, don’t dismiss these.
Here’s one thing I’ve noticed about horn speakers. Because the efficiency is so high, it’s much easier to use the drivers out of their normal operating range without causing over-excursion problems. This is why you’ll find so many two-way horn designs. You can push most tweeter horns so that they work down to around 2Khz, and keep the frequency response fairly flat. Unfortunately, this results in a less than pleasant off-axis response at higher frequencies. The horn problem most people refer to as "honking" is most obvious with two-way horn designs, and I’ve never liked them because of it.
When the engineers at Klipsch were designing the Tractrix midrange horn that is used in the Forte II, they found it could be used up to 20Khz if they played with the EQ on the driver. They didn’t do so; instead, there is a separate tweeter horn for the very high frequencies. Limiting the bandwidth used for the midrange horn lets it cover a horizontal area of 60 degrees smoothly while controlling the vertical coverage for better integration with the other drivers (see Tractrix Horns in the March 1991 issue of Audio for information how the Forte II was created). The fact that the midrange is so well designed is the primary reason this particular model sounds so much better than the other speakers I’ve heard from Klipsch, or from any other horn manufacturer for that matter.
The midrange is really what makes this speaker sound great. There’s a totally effortless feeling to vocals that comes from a driver operating nowhere near its limits in either frequency response or output level. And the foundation that midrange is working on is very solid. The bass is tight down to 30hz if the associated electronics keep up. You’ll feel little need for a subwoofer.
And if you want peak output, you’ve got it. I’ve measured my speakers clearing 115dB in my room before (with my ears covered, thank you). They sounded about as distorted as your average cone speakers do with 10dB less output (which is what you’d expect with a typical 10dB sensitivity difference). While I certainly don’t recommend listening to anything that loud, it’s nice to know you can use your speakers for low-grade sound reinforcement without constantly fearing damage. The low distortion makes the volume level deceptive; I can listen to these speakers at a considerably higher volume than more traditional designs without ear fatigue. Distortion makes speaker sound loud regardless of the volume, and it’s surprising how much quieter the same volume levels sounds without it present (this is a central concept to Paul Klipsch’s philosophy for the company).
Amplifier matching
With that 99dB sensitivity, you’d think you could use any old amplifier and have plenty of power. This is not at all the case. In order to match the output levels of the drivers (those horns are even louder than that without some padding), Klipsch uses some very unique matching techniques using things like a type of transformer. (see A Visit to the Klipsch Kingdom in the 4/89 issue of Speaker Builder for comments from Paul Klipsch on their autoformer design). Transformers are obviously inductive, as they are made out of inductors. What this means is that while the amplifier used doesn’t need to have a very high power output in typical terms, it does need to be able to deal with the very difficult load that inductors present. Using a cheap receiver to drive these speakers just because you don’t need much power is the wrong approach. What you need is a high- current amplifier that can deal with difficult loads without introducing problems.
One of the problems you’ll constantly fight with these speakers is that any components that might sound a bit harsh with other speakers will have that harshness revealed in all its glory. Use a typical cheap CD player and a pair of these speakers will drive you from the room. The amplifier matching in particular can introduce an incredibly rough sound. Back when I was using an Adcom GFA-555 with these speakers, an amplifier generally recognized as being a bit too aggressive in its treble, I had to deal with a level of sibilance that was almost unbearable. The Proton D1200 amplifier I current use is a very good match, but you can’t buy them anymore. Essentially, I recommend trying amplifiers from manufacturers known for producing laid-back components. I’ve had excellent luck building a system around these speakers with components from Rotel, and I have no reason to expect that their power amplifiers would be a bad match for these speakers (and they even make inexpensive, low-power models that still have excellent current driving ability). The tube amps I’ve tried all sound terrific with these speakers. A 35w/ch Dynaco ST-70 is plenty of power to drive a pair to ear-bleeding levels with no problems.
Placement
The other thing that really can bite you and leave a bad impression of these speakers is how you place them. All of Klipsch’s speakers are designed to be placed closer to the corners than typical designs. I like these best sitting about 1-2’ from the left, right, and rear walls. Pull them far out into the room and they don’t sound as good. Another things to watch out for is toe-in. Most people angle their speakers so that the drivers are directly facing them. Bad idea here--you want these facing directly forward, with no toe-in rotation toward the center. When pointed right at you, the harshness that’s always waiting around for the unwary comes right out. The off-axis sound is much smoother and more pleasant to listen to. The manual that comes with the speaker has very generic recommendations that recommend toe-in for all their speakers; ignore all of their suggestions. They may very well be true with other models, but with the Forte II they are just plain wrong (current production might have a revised manual that gives better advice).
Don’t wait too long...
Two warnings. First, if you’re interested, start moving now. I’m told that the rerelease of these speakers is a temporary thing, and that they are going to disappear again in some indeterminate period of time. Second, I haven’t actually had a chance to try out a sample from the current product run. I don’t see any design changes, and they seemed to sound about the same during a brief listen at the local dealer, but I’m not 100% certain these are exactly the same speakers I’m used to. Even if I had a pair, I couldn’t tell you for sure for a while--it took me six months to get my old pair broken in properly (you really have to move that woofer around to stretch the cone and radiator out to get the bass going as deep as it should). The bass does take a while before it sounds exactly right, and the volume level required to break these in right is enough to get your average dealer evicted if they tried it in the store.
As far as I’m concerned, the Forte II is a terrific design competitive with any speaker in the $1000 price class is every category. And they are possibly the best available in terms of deep bass output, sensitivity, and maximum output for that much cash. If you give them a fair audition, following the suggestions I gave for matching components and room placement, you may just find that inexpensive horn speakers can sound better than you thought possible.
.....GS
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:yes:
Here's a cool link the PWK Museum at New Mexico State University:
http://abacus.nmsu.edu/~shoran/ece/ece_facilities_klipsch_museum.htm
shelbydave
New Member
I had the opportunity to meet him in Germany in 1985. Since his family was Austrian, he would take his vacation in Europe, make appearances at the Military Audio/Video stores, and write his trip off as a business expense.
slovell
Well-Known Member
anybody still using kg5.5's? i've had mine since '92, tried a couple of other brands, and eventually went back to my 5.5's. i just can't seem to get away from them. one of the best rock speakers i've ever heard and they're pretty damn good on everything else. anyone know of any good mods for them?
I met him a few times, and he was quite a character
I was working at a Klipsch dealer in Tulsa, OK from 78-82 (one of two dealers in the state, and we sold a lot of them). He came to our store several times, since we were a driveable distance from Hope; I still have the set of audio papers they they published.
He was quite a character, and he offered us each the "Stolen from Paul Klipsch" pocket knife (but you had to take it when he set it down; he didn't hand it to you), and the Klipsch belt buckle that I won in a sales contest.
I believe that I may be the one who introduced him to the Tractrix horn. I had been subscribing to Speaker Builder magazine, and had read an article about the design, and its dispersion characteristics and lack of 'honkiness', so I wanted to get his take on the article, He said that he hadn't heard of the design, so I made a copy of the article for him. I was a bit surprised when I saw it appearing in their products about 5 years later.
I was working at a Klipsch dealer in Tulsa, OK from 78-82 (one of two dealers in the state, and we sold a lot of them). He came to our store several times, since we were a driveable distance from Hope; I still have the set of audio papers they they published.
He was quite a character, and he offered us each the "Stolen from Paul Klipsch" pocket knife (but you had to take it when he set it down; he didn't hand it to you), and the Klipsch belt buckle that I won in a sales contest.
I believe that I may be the one who introduced him to the Tractrix horn. I had been subscribing to Speaker Builder magazine, and had read an article about the design, and its dispersion characteristics and lack of 'honkiness', so I wanted to get his take on the article, He said that he hadn't heard of the design, so I made a copy of the article for him. I was a bit surprised when I saw it appearing in their products about 5 years later.
pmsummer
simul justus et peccator
I've got one of those and have wondered if his way of giving them out was a bit of a joke (by not putting it in your hand, you weren't "given" it, and by picking it up where he left it, you "stole" it).
Thanks for the info on the Tractrix!
And welcome to AK!
mikewish
Active Member
I still have a pair of coffee mugs with the logo and the "stolen from Paul Klipsch" on it. I hung out at the plant in Hope WAY too often. Of course I lived in Hope, so it was pretty easy to do. BTW, the Dope from Hope was a double entendre from the counter culture that was Hope, Arkansas. An incredible place to have lived during the '70's.
beatcomber
AK Member
So, do any of you agree with PWK's suggestion that Klipsch speakers should be toed in 45 degrees at both corners?
Rather difficult to NOT set up K-Horns that way. 
bonaccorso
Magicflute
Bridged Center Speaker
Yes, I have a Belle Klipsch as the bridged center speaker between my Klipschorns.
I, originally, purchased my Klipschorns in '79, and, out of necessity, placed them along the short wall of my family room. I then moved to a home with a suitable long wall of 22 feet. I decided that Paul Klipsch must have known what he was talking about, so I made the investment and purchased the Belle. I have never had a moment's regret. The sound stage opened-up before my very ears, and the result was a three-dimensional image of wall-to-wall sound. If the bassoonist is a little behind and to the right of the flutist, that is where he appears in the sound stage.
If memory serves me correct, I think I recall that Paul Klipsch stated that the ideal set-up is two corner speakers, placed as far apart as possible (the further, the better), with a bridged center speaker to fill-in the hole.
Anyway, I have, over the years, heard many great speaker systems, and I always felt that, in comparison, my system held-up quite favorably, indeed.
Yes, I have a Belle Klipsch as the bridged center speaker between my Klipschorns.
I, originally, purchased my Klipschorns in '79, and, out of necessity, placed them along the short wall of my family room. I then moved to a home with a suitable long wall of 22 feet. I decided that Paul Klipsch must have known what he was talking about, so I made the investment and purchased the Belle. I have never had a moment's regret. The sound stage opened-up before my very ears, and the result was a three-dimensional image of wall-to-wall sound. If the bassoonist is a little behind and to the right of the flutist, that is where he appears in the sound stage.
If memory serves me correct, I think I recall that Paul Klipsch stated that the ideal set-up is two corner speakers, placed as far apart as possible (the further, the better), with a bridged center speaker to fill-in the hole.
Anyway, I have, over the years, heard many great speaker systems, and I always felt that, in comparison, my system held-up quite favorably, indeed.
MitchfromVA
New Member
sxty8goats
Super Member
You would think that in this day of 7.2 Receivers, they would incorporate the center channel when playing a stereo source. 3 channel stereo if you will. I have an option to use '7 channel' stereo but that just gets messy.
In one of the 'Dope from Hope' papers, he published a simple circuit that would take stereo line inputs, and output stereo plus a summed signal for the center amp. I believe that it was four 47 kohm resistors that went from left in -> left out, left in -> center out, right in -> center out, and right in -> right out. It went inline between preamp and power amps.
