What Separates Do You Have

[Bret_Salyer]

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The RF-7s ... which is different when the impedance is not exactly 8 ohms. Sound and Vision rated them as a 6 ohm speakers. I think that they are closer to 4 ohms, but lack the testing gear to measure for myself.

Bill

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I believe Klipsch describes them as "8 ohm compatible".

Griffinator, what do you think about Sunfire amps?

[MrMcGoo]

A few last thoughts about amps on Klipsch speakers: Klipsch has a 650 watt Bash amp in my RSW-15. They have a 1,000 watt amp on the THX Ultra2 subwoofers. I haven't heard any forum member with either sub complain that it is over powered. Nor has anyone on the forum been critical of said subwoofer amps' power rating.

Why are folks offended by Sunfire amps with a S/N ratio of -118 db and are not offended by bigger amps of lower quality on a speaker that covers only a tiny range of frequencies? My RSW-15 goes 13 cps (Hz) lower that my RF-7s which cover a much greater frequency range.

Are the engineers at Klipsch incompetent at specifying subwoofer amp sizes? Or maybe those darned marketing types at Klipsch are responsible for insisting on all that "useless" power for the subwoofers. Bass is really easy to reproduce on the RF-7s, even if you do not have a folded horn design like the Khorn. Perhaps Klipsch has designed inefficient subwoofers that only hit about 120 useless decibels down low.

Bill

[Griffinator]

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On 6/28/2005 12:52:23 AM Bret_Salyer wrote:

Griffinator, what do you think about Sunfire amps?

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I don't have any inherent problem with the Sunfire amps. Every SS amp Bob Carver ever made has a very distinctive "Bob Carver" sound to it. I'm not a huge fan of that sound, in all honesty. However, I'm not going to disparage the amp just because it doesn't suit my taste.

My whole argument here (which Mr McGoo completely failed to address) is that, when comparing 200wpc amplifiers for home theater purposes, the difference between one that can drive 4 Ohms at 300wpc vs. one that can drive 400wpc at same load is unimportant. What is important is that they are capable of driving those loads in stable fashion.

Obviously, Mr McGoo is insisting that he listens to his HT rig at these outrageous volume levels, (running two Sunfire 200wpc amps to clipping on a 7-channel rig featuring RF-7 mains) which further reinforces my hypothesis that his hearing has already been damaged.

I, OTOH, like my ears in their current condition, and wish to keep them that way as long as possible. So, while I like the headroom available on my amplifiers, I choose not to push them to their extreme limits for the sake of my ears.

Oh, and BTW - I still don't believe in double-blind A/B/X tests that demand more than 3-4 repetitions. Ear fatigue is a very real problem that fundamentally invalidates any such testing. Ask any mixing engineer. Spend too much time listening to the same program material repeatedly and your ears start to become desensitized to the subtle differences.

I could literally (and I'll happily do it, if you insist) set up an A/B/X test with a cheap old Onkyo stereo amplifier and that same Sunfire Grand that would yield virtually the same results as any other A/B/X amplifier comparison, after 20 repetitions. You want to tell me there's no difference between them?

[J.4knee]

Q-MAN /Nicholtl,

Question, do either of you know what the input sensitivity on the C1 analog audio inputs. My reason for asking is for TT usage. My HOMC cartridge is rated at 1.6-mv output. My current Yamaha is rated at 2.5-mv for the MM phono input and I know the MX 135 is rated at 4.5-mv. I know Nick has a Music Hall set up do you use a step up for it?

[nicholtl]

Hey Jim, I have no idea what the sensitivity voltage is, although the dudes and dudettes over at Club Parasound - http://www.htguide.com/forum/forumdisplay.php4?f=21 - would.

I know that the C1/C2 has no phono section, and so yes, a phonostage is necessary. I use a Musical Fidelity X-LPS v3.

Might I ask why you're so curious about Halo products? Are you thinking about joining the fold...?

[MrMcGoo]

"Obviously, Mr McGoo is insisting that he listens to his HT rig at these outrageous volume levels, (running two Sunfire 200wpc amps to clipping on a 7-channel rig featuring RF-7 mains) which further reinforces my hypothesis that his hearing has already been damaged."

Griff: How do you get the idea that I insist that I listen at insane volumes when I specfically stated that I listen at about 250 milliwatts, i.e., a quarter of a watt? Perhaps you don't read my posts, you just criticize what I did NOT write. You probably also infer that anyone with a Porche 911 constantly drives at 150 miles per hour.

While we're here at a quarter of a watt, it is worthwhile to note that many transients can be 30 decibels higher than the average program material. A 30 decibel transient requires a 1000 times more power for a very brief instant. One thousand times a quarter of a watt is 250 watts. A 200 watt amp may not be able to produce 250 watts for that tiny fraction of a second and therefore may clip.

I formerly used a 140 watt B&K amp that produces 185 watts at 4 ohms. Under Griff's theory it should have excellent bass response since it could produce the needed watts in most insatances. Unfortunately, sound reproduction does not work that way. The B&K 140 watt amp produced muddy bass. A 225 watt Sunfire produce much better bass.

If an amp cannot double its current output when a speaker's impedance drops in half, one of two things is going to happen. It will either clip (SS) or the output voltage will drop (tubes) and not accurately reproduce transients. Both result in less than ideal sound reproduction.

Bill

[Griffinator]

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On 6/29/2005 1:43:23 AM MrMcGoo wrote:

Griff: How do you get the idea that I insist that I listen at insane volumes when I specfically stated that I listen at about 250 milliwatts, i.e., a quarter of a watt? Perhaps you don't read my posts, you just criticize what I did NOT write. You probably also infer that anyone with a Porche 911 constantly drives at 150 miles per hour.

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Have you seen the clipping indicators on a 200 watt amp flash on 102 sensitivty Klipsch speakers on the 1812?

I took this to mean that you have, and do...

While we're here at a quarter of a watt, it is worthwhile to note that many transients can be 30 decibels higher than the average program material. A 30 decibel transient requires a 1000 times more power for a very brief instant. One thousand times a quarter of a watt is 250 watts. A 200 watt amp may not be able to produce 250 watts for that tiny fraction of a second and therefore may clip.

Sure. Except you are enslaving yourself to the Root-Mean-Square rating of the amplifier. Most amplifiers rated to 200wpc RMS or program are capable of producing peak outputs of twice that or more! If all you're worried about is that cannon-fire transient, I can personally assure you that every 200wpc amplifier on the market is going to produce 250w for that "tiny fraction of a second" and will not clip. Thank you for clarifying your position as to where you thought all this wattage was necessary, because I can now drop the whole objection about the condition of your ears. Peak output is not the same as RMS output, sir. Please educate yourself on the differences.

I formerly used a 140 watt B&K amp that produces 185 watts at 4 ohms. Under Griff's theory it should have excellent bass response since it could produce the needed watts in most insatances. Unfortunately, sound reproduction does not work that way. The B&K 140 watt amp produced muddy bass. A 225 watt Sunfire produce much better bass.

This is called obfuscation, sir. I have, repeatedly in this conversation, insisted that I am comparing apples to apples - 200wpc amplifiers to other 200wpc amplifiers. Furthermore, I have never mentioned "bass response" at any point in this thread. You've already handed out the math that indicates why your B&K couldn't hang with the Sunfire - your 1/4w listening volume puts your cannon fire at a decibel range the B&K simply cannot produce - demanding 256 WPC from it!

If an amp cannot double its current output when a speaker's impedance drops in half, one of two things is going to happen. It will either clip (SS) or the output voltage will drop (tubes) and not accurately reproduce transients. Both result in less than ideal sound reproduction.

Silliness. You didn't prove this point with your above arguments. You said "It takes 256wpc to drive +30dB transients, therefore an amplifier must double its output at half the resistance load"

This is akin to a physicist saying "The earth is round, therefore a nuclear reactor must produce 1.6 gigawatts of power per second or be incapable of supplying its grid."

You have offered nothing to support this assertion.

Meanwhile, I have repeatedly demonstrated that a 200wpc amplifier that is capable of producing at least 300wpc (150% of 8 ohm rating) at 4 ohms is more than sufficient for any Klipsch speakers not being used as PA speakers at a rock concert.

[Griffinator]

Addendum...

In conclusion, Bill, your assertions about your own listening habits further reinforce my statement that an amp like the Sherbourn 5/1500 or 7/2150 can deliver just as well as your Sunfire at standard listening volumes. You have admitted that all you need is 250wpc peak program to be satisfied by your amplifier. Where exactly do you get the idea that you still need an amp that delivers 400wpc into 4 ohms, as opposed to one that delivers 300? Either still leave available power, and neither is capable of handling anything beyond that 30dB peak. Your amp would be sucking wind just as much as any other if your start point was at 1/2 watt instead of 1/4, because the preamp would be demanding 512 watts peak from it! Hell, you'd be off in search of a megawatt monstrosity at that point, insisting that the Sunfire was every bit as feeble as your old B&K.

My best suggestion to you, sir, is that you seriously look into the Crown xS1200 series amplifiers, to be used as monoblocks for your RF-7's. As 8-ohm bridged units, they are capable of delivering 2300wpc RMS. Although, I'm not sure. They only do 3Kw at 4ohms. Never mind, they must be inferior designs...

[J.4knee]

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On 6/29/2005 1:11:27 AM nicholtl wrote:

Hey Jim, I have no idea what the sensitivity voltage is, although the dudes and dudettes over at Club Parasound -

http://www.htguide.com/forum/forumdisplay.php4?f=21

- would.

I know that the C1/C2 has no phono section, and so yes, a phonostage is necessary. I use a Musical Fidelity X-LPS v3.

Might I ask why you're so curious about Halo products? Are you thinking about joining the fold...?

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Yeah I am considering two pre/pro units right now, although neither is in my immediate future. The first one being the McIntosh MX 135 and the other one being the Parasound HALO C1. I was also somewhat impressed by the Aragon stuff this weekend at Klipsch. What I may end up doing eventually is get the power amps I want and use my Yamaha as an interim Pre/Pro but again nothing in the immediate future.

[Q-Man]

The manual reads like this, and I don't think this will help much.

Input sensitivity for THX reference level is 2 V rms for the analog inputs.

I wish McIntosh would offer more features on their AV/processors. The Parasound stuff is also some what limited, but you can program front effect channels with the C1 and C2 , like with your Yamaha. I used my Yamaha as a pre-pro for quite a while.

[mbajner]

recently purchased an Anthem MCA50

its a 5 ch amp at 180 watts per

it is my first separate and so far so good

I audtioned this amp vs a Sunfire

I did hear the difference and like the Anthem better

the speakers at the audition were RF7's

[MrMcGoo]

Griff,

There you go again twisting my words. I listen on AVERAGE at no more than 250 milliwatts. With a 30 decibel peak, the amp is required to produce 250 watts for a tiny fraction of a second.

The THX standard has folks listening at 75 decibels at home with peaks as high as 105 decibels. I like to have the capability to listen at 85 decibles if I so choose. That puts peaks at 115 decibles. This is very rare for me, but it happens.

Some movies seem to have peaks in excess of 30 decibels. For example, Master and Commander in DTS seems to have peaks over 30 db.

In short, I recommend that anyone with a home theater use quality amps that have AMPLE headroom, if possible. What is so difficult to understand about recommending headroom?

If the amp cannot supply the needed current it does not have the headroom as far as I'm concerned. Amps that cannot produce the needed current and voltage will clip, bass will be muddy and frequency response will suffer.

I had a good 140 watt amp by B&K, but its bass was not good on the RF-7s. Under your theory it should be just fine because RF-7s are so sensitive and the B&K can deliver 185 watts into 4 ohms.

In reality good amps like the B&K Reference amps are much better. From 140 watts to 200 watts is less than a 3 decibel increase in sound output, yet the 200 watt amp sounds much better to me. Why? Because it has a better power supply and more output devices per channel, 5 pairs versus 2 pairs of MOS-FETs. The B&K Reference amp puts out 375 watts into 4 ohms, i.e., it comes close to doubling its current output as the impedance drops in half.

The same is true for Sunfire allegedly. Bob Carver plays with the numbers on Sunfire amps, but they do perform very well IMO.

I do not recommend separate amps for RF-7s that cannot come close to doubling output from 8 to 4 ohms. Why? Because the 2.8 ohm minimum impedance of the RF-7s is not an easy load, high sensitivity not withstanding.

Bill

[J.4knee]

Oh would you 2 quit pee'in on each other!?!?!

[gibby214]

While on the topic of Bob Carver. Does anyone know if his work goes into the Carver Professional Amps.. specifically the digital tripath ones like Minnmale uses. Or is the name just coincidence?

Gib

[MrMcGoo]

Gib,

Bob Carver sold his company and his name many years ago. In fact he has sold more than one company. He has no connection to Carver Pro or their digital amps. To the best of my knowledge, sunfire is Bob Carver's only affiliation currently.

As a side note, Sunfire does repair gear designed and sold by the companies Carver used to own.

Bill

[IndyKlipschFan]

Anyone with a Porche Turbo drives at 150 miles per hour.<< (Slightly edited..)

Been there, done that,.. Oh man, 55 MPH seems like crawling after driving 157 MPH...LOL

[Griffinator]

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On 6/29/2005 8:15:17 PM MrMcGoo wrote:

Griff,

There you go again twisting my words. I listen on AVERAGE at no more than 250 milliwatts. With a 30 decibel peak, the amp is required to produce 250 watts for a tiny fraction of a second.

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Sorry, but I didn't twist anything. That was the whole point I made above - that nearly any 200wpc amplifier will be able to deliver 250wpc for a tiny fraction of a second (also known as a peak)

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The THX standard has folks listening at 75 decibels at home with peaks as high as 105 decibels. I like to have the capability to listen at 85 decibles if I so choose. That puts peaks at 115 decibles. This is very rare for me, but it happens.

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85 dB on a pair of RF-7's, even by themselves, from 12 feet away, would be more along the line of 1/16 of a watt, not 1/4 of a watt as you previously specified. (98dB @ 1W, 12 feet, 95dB @ 1/2W, 92dB @ 1/4w, 89dB @ 1/8W, 86dB @ 1/16W)

If this is a rare listening volume for you, and you typically listen at lower volumes, then you're using even less power than you think...

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Some movies seem to have peaks in excess of 30 decibels. For example, Master and Commander in DTS seems to have peaks over 30 db.

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See above.

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In short, I recommend that anyone with a home theater use quality amps that have AMPLE headroom, if possible. What is so difficult to understand about recommending headroom?

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I completely agree with the premise. I'm just making the point that any amp that is stable at 4 Ohms and delivers at least 50% more power than at 8 ohms has a sufficiently robust power supply to handle a pair of speakers that dip into that territory. Whether your B&K 140 watter could hang is irrelevant. I've been a constant proponent of 200wpc SS amplifiers for home theater applications for a very long time. You keep putting words in my mouth about the B&K, while continuing to ignore the points that I am making here.

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If the amp cannot supply the needed current it does not have the headroom as far as I'm concerned. Amps that cannot produce the needed current and voltage will clip, bass will be muddy and frequency response will suffer.

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The question here, and the only real point of contention between us, is exactly how much current is actually necessary. I've already given you hard factual information that refutes your position that 400wpc @ 4 ohms is a benchmark for "needed headroom". You, however, refuse to address that point, and instead set up straw men for yourself, which you then knock down easily, though they are still irrelevant to my position and my arguments.

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I had a good 140 watt amp by B&K, but its bass was not good on the RF-7s. Under your theory it should be just fine because RF-7s are so sensitive and the B&K can deliver 185 watts into 4 ohms.

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Straw man. I never said that. Your B&K not only doesn't deliver 200wpc, which I have stated repeatedly was my personal benchmark for HT amps, but it also doesn't deliver 150% of its rated 8 Ohm power at 4 Ohms. Obviously its power supply isn't up to the task.

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In reality good amps like the B&K Reference amps are much better. From 140 watts to 200 watts is less than a 3 decibel increase in sound output, yet the 200 watt amp sounds much better to me. Why? Because it has a better power supply and more output devices per channel, 5 pairs versus 2 pairs of MOS-FETs. The B&K Reference amp puts out 375 watts into 4 ohms, i.e., it comes close to doubling its current output as the impedance drops in half.

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No argument. Still doesn't prove that doubling current at half impedance is necessary for a quality amp.

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The same is true for Sunfire allegedly. Bob Carver plays with the numbers on Sunfire amps, but they do perform very well IMO.

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I didn't say anything to the contrary. They are good amps.

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I do not recommend separate amps for RF-7s that cannot come close to doubling output from 8 to 4 ohms. Why? Because the 2.8 ohm minimum impedance of the RF-7s is not an easy load, high sensitivity not withstanding.

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One has nothing to do with the other. You keep trying to make this connection between the power doubling and the impedance drop. You also continue to try and connect peak power demands with the impedance drop. Sorry, but "if a then b" has to be proven, not just stated. You've offered no evidence to support your assertion, while I've offered plenty to refute it.

Oh - and J4 - I'm not pi$$ing on Bill. I'm trying to have an intelligent debate with him. Unfortunately, it doesn't seem to be working out very well, because he's not arguing the points I've been making, he's just setting up straw men and knocking them down, then following with leaps of logic. Classic logical fallacies all over the place.

[Speedball]

Gee Griff, sounds like you believe in a lot of numbers and letters...

[MrMcGoo]

Griff,

You are getting boring again. You seem to like urinating in the public forum as well.

A quick look at your numbers leads me to believe that you have assumed that the RF-7s at 102 1w/1m. At best, they are 99 db/1w/39.36 inched or 1 meter, not 12 feet per Sound & Vision. Klipsch rates them at 102 db/2.83v/1m which is consistent with Sound & Vision since RF-7s are not a true 8 ohm speakers. They are merely 8 ohm compatible.

Home Theater Mag. rated RF-7s lower at 95 db/1w/1m. If you want dates and page numbers for the independent sensitivity tests I can supply them. When DeanG doubted the numbers, I sent him copies of the relevant reviews which he publicly acknowledged on the forum. I can do the same for you, but would rather send them to someone with a scanner that will post them so that everone can see the facts as indepenmdently determined.

If Home Theater Mag.'s numbers are anywhere near accurate, your numbers fall on their keister, especially when you consider that most of my music is two channel.

You seem to assume that I have a watt meter on at all times when I have the system playing. My numbers are OBVIOUSLY only rough estimates that are worst case, since I do not want to risk damaging my system. That is what folks with common sense do. It appears that you think that it's ok to risk clipping on the 1812 or Master and Commander or any other movie with explosions that may be mixed a little hot. I do not and it's my system.

Minn_Male_42 has KLF-30s also rated at 102 db sensitivity. He plays the 1812 Overture from Telarc in 5.1 SACD, and his clipping indicators show clipping when the cannon shots go off. His Carver Pro ZR 1000 amp is either 200 wpc or 225wpc, I can't remember which. Maybe his amp is lying to him about clipping. Also, the peaks may be closer to 40 db; I don't have a scope to measure them. Forty db peaks would require 10,000 times the power.

We both listen to the 1812 at about the same levels from time to time. Just to let you know that I play it regularly, I have 4 digital copies that I use. Three of the 4 are two channel versions. It's worth noteing that most home amps do not have clipping indicators.

I do not recall you claiming that Klipsch has overpowered its subwoofers. Again, are you claiming that there is absolutely no need for a 650 watt amp in the RSW-15 or 1000 watts on the THX Ultra2 subs?

[MrMcGoo]

Dear forum members,

So that you can draw your own conclusion and make your own decisions on amplifier size, I invite you to visit the Crown amp site that has an amp size calculator. It's at the folowing URL: http://www.crownaudio.com/apps_htm/designtools/elect-pwr-req.htm

I ran the following calculations at the Crown amp site based upon the Home Theater Mag sensitivity of 95 decibels for an RF-7 from one watt and a listening distance of 4 meters (~12 feet):

Level for listening: 75 db

30 db headroom = 160 watts required

32 db headroom = 254 watts required

35 db headroom = 506 watts required

Level for listening: 85 db

30 db headroom = 1,600 watts required

32 db headroom = 2,536 watts required

35 db headroom = 5,059 watts required.

Again, the THX specs are for 75 decibel listening levels with 30 db of headroom for peaks. As you can see, if you listen to movies mixed a little on the hot side or ever listen over 75 db average level, then you need lots of headroom for 95 db efficient speakers. Needless to say the numbers change when you have an array of three speakers up front, but then the rC-7 is also less sensitive.

Now, back to the Crown site to run the numbers for 99 db sensitivity from S&V.

Bill