RF3II owners

[msaiba]

The B&K is 150 watts per channel(ST202) and It improved the sound a lot when I added this to my system bypassing the receiver amp.My speakers are RF-3's what's the difference between RF-3's and RF-3 II anyway? Do you mean to say that my receiver may not give out the preout and normal output simultaniously?

Thanks,

[easylistener]

No it probaly does but you don't want to run power to the speakers with two sources with the jumper straps in. Thats why I said you could biamp the speakers. You could use the reciever for the top post and the B&K for the lower post, just make sure you take the jumpers out between them. I don't know if it will improve your sound though because the B&K amps I heard are great amps.

[msaiba]

In your last reply you said "Most recievers you can not bridge" what does that means?

Thanks,

[Frzninvt]

Bridging means you take two stereo channels and combine them (strap) to create a more powerful single mono channel. Most if not all A/V receivers are NOT capable of doing this, nor are most regular two-channel receivers. I am a firm believer in using lots of clean outboard power. My Denon AVR-4800 rated @ 125W X 5 and is only running my KG-1 ( surrounds everything else is powered by outboard high current amplifiers. My DBX amplifiers are configurable which makes them very versatile since they can run in 2, 3, or 4 channel modes. My BX-1 sends 100W to each of the Khorns and 400W to the center channel La Scala @ 8 ohms. It is capable of running down to 1 Ohm and can produce a whopping 1200W for the bridged channel and 400W to the stereo channels. It will never be run at that level due to the efficiency of the Klipsch but with those kind of power reserves the dynamics and clarity are right off the scale. I also runs Class A up to about 30 watts or so for a nice warm tube kind of sound. I also use a DBX BX-3MkII in 4 channel mode 125W X 4 to run the rear La Scala's and Effects Heresy II's. A third DBX BX-2 amp is dedicated to the passive subwoofer @ 250W per coil. Essentially the Denon performs as a preamp and the outboard amplifiers do the rest. As for the braced RF-3's sounding better than the RF-7's and not needing a subwoofer c'mon gimme a break. Bracing and foam, not even acoustic foam at that wont work miracles. The correct material to use is fiberglass or cotton batting, but then you are altering the internal cabinet volume that the woofer see's. Some people just don't get it.

[easylistener]

If you would do all of that wouldn't it bring the hz up because of the smaller cabint?

[Jef]

To Jalen01

A Denon goes up to +20, zero is 1 Watt (with a normalized input signal) and -5 means you where reaching decent levels with rougly 0.25 Watts :-)

The increased bass control with high power amplifiers is a direct consequence of their increased current handling abilities (and design to handle complex (inductive and/or capacitive) loads for some models).

This means that amplifier A - rated 50 Watts and amplifier B rated 400 Watts will sound different when both are delivering an equal 1 watt, amplifier B is able to deliver and sustain much larger currents into the complex load a large woofer presents.

Harman Kardon, for instance, refers to this directly by pointing out that their amps have high current capability (35 and 45 Amps), if you calculate this rating into 6 ohms the amplifier 'would' deliver 12150 Watts (!) at that moment. 'Would' because these calculations asume a resistive load, which is incorrect, but that it's the increased current capability that 'control' the woofer making him sound thighter.

Not an add for HK as a lot of other amplifiers can deliver high currents as well.

Jef

[USparc]

Yep, some people dont get it.

The cabinet design and construction directly affects sound quality, especially overall clarity. The materials determine how free the cabinet is from unwanted resonance. MDF (medium density fiber board) is preferred because of its high density, the thicker the better. This is particularly critical on the front baffle where the drive units are mounted. Internal bracing also plays a vital role in controlling resonance, smoothing out midrange response and reducing box coloration. The sound is generated by the drivers, not coloured by the cabinet. All high end speaker designers are trying to achieve this!

Besides, what is the function of the cabinet:

When a speaker moves forward, air in front of the cone is compressed. At the same time, air in back of the cone is rarefied (stretched). If there is a pathway for the compressed air to get behind the cone, it will do so. This process reduces the amplitude of the soundwave. It is therefore necessary to use some type of enclosure, in order to keep the soundwaves from cancelling each other out. That is the task a cabinet has and certainly not to produce sound.

Hey, I just try to improve things. This is definitely the way to go.

More power or/and larger woofers in a larger unbraced and therefore not rigid enclosure will result in even more cabinet coloration. The cabinet sound will be smeared all over the place which compromise clarity and detail in the sound.

[easylistener]

usparc

I guess I understand a little. I think it works on paper, but am not a true believer. All I know is that the added power made a drastic improvement in the sound. On paper they said that a dragster will never go over 300mph in a 1/4 mile. They have and gone faster. Send my that list of supplies that you gave to the other guy and I will try it out on my 3II's. I have some extra time. I am not saying you are wrong but I would like to hear it for myself.

[Jalen01]

Jeff,

Thanks for the correction........These Reciever's and Pre's with Db read-outs are all still new to me. I'm still looking at a little red dot (light) on my Pioneer d906s, LOL. -05 was as high as I was willing to push it, not being my gear and all. But, my buddy did in fact max it out a couple times in my presence on both 2ch & HT. And I have to stand by my comments that they are "Light In D A$$, and may not be enough for His big ol' 7's. Especially, when comparing any reciever+ decent outboard amp. I guess I've gotten a little spoiled using mine.

Jalen

P.S. Sorry for all the bad grammer & Spelling all......See Kids this is why we need to stay in school.

[Jalen01]

Jef,

I just re-read your post. I'm trying to figure out why the Denon (and probably other models too) would go from like -80 all the way to +1 and only get (1) one watt. So, all of the Denon's "109" remaining watts are in the last 19 Db's of the dial???? That just seems really strange to me. I guess I'm just old school on this issue then.

Jalen

[easylistener]

That doesn't seem right to me. The wattage does start to go up faster aftor -20. I was told that at 00 is were the max wattage is at the rating. I have taken my 4802 to +02 and it was distorting badly.

[USparc]

Ahm, The volume dial are normaly in db. It is a relative number.

You can calibrate your receiver at 0db to produce 75db pink noise to set the THX reference volume. I had to set the 75db pink noise to -10db on the receiver because the correction doesn't go that far to reach the 0. (Actually it does but the correction is set at the max of -10db)

The watts that your receiver is using to drive the speaker at a certain soundpressure depends on the sensitivity of the speakers itself. In case of RF-3's 98db/1W. The volume dial just gives you the added soundpressure relative to the reference. If you set the volume 3db higher on the receiver (-20 to -17) the amps have to dubbel the wattage. It follows a logaritmic curve.

Starting from the sensitivity of 98db/W we can find the needed power.

98db - 1W

103db - 2W

106db - 4W

109db - 8W

112db - 16W

115db - 32W

118db - 64W

121db - 128W

124db - 256W

As you know that THX specify that a system must handle 105dB with peaks of +10db

(115dB), klipsch RF-3's have enough with 64W.

So the wattage dubbels each time you add 3 db on your receiver.

If you have an SPL meter set 1 m in front of the RF-3 and measure 98dB.

You know at what setting the receiver sends 1W to the speaker.

[Jef]

Hi Jalen,

for some reason Denon has chosen to make their readout max at +18 (for the models I could verify 1603,2803 and 3803) - this is clearly written in the manual - if you have increased the preset of a channel the max readout becomes 18-(value of increase).

O (zero) is not exactly 1 watt but very close to it.

Your deduction is correct - our hearing is logarithmic, a 10 dB increase equals a tenfold increae in power but only roughly a doubling in perceived loudness. see table below :

1 Watt - 10 Watt - 100 Watt - 1000 Watt

0dBW - 10 dBW - 20dBW - 30 dBW (dBW means dB relative to 1 Watt)

Diffences between 80 or 90 even 130 Watt amplifiers are barely noticable as the difference between the 130 and 80 Watt amplifier is only about 2 dB - at high volumes our ear cannot distinguish differences of 2 dB anymore.

The differences you do hear between them are a result of the current abilities (as I described previously), different design and components but definitly not because of the increase in Wattage. Again ref the lower rated HK amps with large current abilities that are reported to sound louder than higher Wattage amps.

to easylistener,

I can only refer you to your manual, I have no idea why your amp would distort from +2, I can play undistorted up to +5 even +7 (this is incredibly loud).

It does depend on the input signal - not all sources output the same max signal - but still.

Jef

[easylistener]

Jef-I never said it didn't go higher. Mine will go up to 18db, bit it starts to distort. This is kind like the old recievers when you turned them up past half way, they would distort and start to clip. I understand for ht denon presets the ref. level is 00, and that is loud. It is loud but not clean, it sounds stressed. This is why I am saying if you want to go loud you have to get an outboard amp. The diffence is night and day. I am also not saying denons are bad, I love mine. It just needs a better amp for my taste.

[Jef]

Hello Easylistener,

it seems I misunderstood you, indeed if you want a more unrestricted sound you have to provide more headroom, at the settings we are discussing the amp will reach its limits quiet easily. But as you wrote even '0' is allready loud on a RF3 (or equally efficient speaker).

At these levels the room makes an important contribution too, in a heavily dampened room you will hear the distortion faster than in a room with reverberation as this tends to mask the onset of the distortion.

Jef

[easylistener]

Jef now I can go twice as loud with not hearing any distortion. Plus they sound better. Do you now if the rf3II are fused? I am worring about blowing them.

[USparc]

I dont think the RF3IIs are fused. The Rf-3 s definitely not.

But blowing them? Now I have to ask. How big is your listening area ?

[easylistener]

12x25 is about the room size. It has two big openings to the side of the room.

[USparc]

Ok, That is about the size of my room (13x21). You are talking in feet I hope, not in meters. I don't think you have to worry about blowing them.

Besides, a clipping receiver can do more harm to the horn then your amps running clean power. Unless you want soundpressures of over 120dB.

[easylistener]

No, no clipping. I am driving them very hard. I am not worried about the tweeter, only the woofers. I don't play it real loud except for a few good songs.