Is bi-wiring worth it?

[jjptkd]

20 minutes ago, derrickdj1 said:

How? 

 

I'm not sure exactly how the "magic" works but I have tested this numerous times and get the same result each time.

 

I take a standard Sunfire Cinema Grand amplifier rated at 200x5 watts @ 8ohms, 400x5 watts @ 4ohms. I first run the speakers with just two channels, then switch to passively bi-amping with 4 channels from the same amp. The difference is exactly what you'd expect if you doubled the power going to the speakers. It gets louder faster on the volume knob and has higher total output before distorting.

[derrickdj1]

I know what you are getting at.  For example if the bass driver needs 50 watts the same signal is being sent to each driver or 100 watts total for the Hi and Lo driver.  Using two amps, each amp in passive bi-amping is responsible for 50 watts.  So, in theory each driver is 3 db louder

 

 The 3 db is only percieved as slightly louder.  To double the percieved volume you need 10X the power.  This is most applicable to a system running the mains as Large and no subwoofer  For example a 1 kHz signal using  1 watt produces 70 db.  Now add a 40 Hz signal that you want to be as loud requires 100 watts.  Add a sub in the picture and XO at 80 Hz and you now need around 11 watts.  See the waste in dynamic headroom running the speakers set to large.

 

Also, running speakers as Large causes more cone movement=more distortion.  The 3 db is not even needed for most listening because the Klipsch speakers are so efficient.  This is why many of us with tube amps and Klipsch are running flea power amp of 4-20 watts.  I run my RF 7 II's off a 40 or 45 watt tube amp for music which is plenty loud.  I also have a 200 watt power amp that I use on the speakers for HT.  Less than 10  watts on the tube amp get me over 100 db with the RF 7 II's ran as Large.

 

Having 300-400 watt amps with most Klipsch speaker is overkill.  All the extra power just goes unused.  If any speaker benefit most from extra amplification is a smaller speaker with lower sensitivity.

 

 

[jjptkd]

23 minutes ago, derrickdj1 said:

Having 300-400 watt amps with most Klipsch speaker is overkill.  All the extra power just goes unused.  

 

By that same logic having speakers with a max output of 121db is overkill for most people? I'm not disputing anything you're saying, just pointing out that passive bi-amping will, at the very least, provide additional watts to your speakers. Whether those watts are needed is a different discussion altogether really. 

[derrickdj1]

In theory you have more watts even though you will most likely not ever used them.  The money could be allocated toward something else in the system.  But, the argument that the extra amp is providing all this detail and power does not hold water in a practical sense for most of us.  I guess the real argument is why not use a sub for the low stuff and get an additional 5-6 db of dynamic headroom running the speakers as small.  This is more than the 3 db from an extra amp.  Even most of the large Klipsch tower speakers can benefit from adding a sub in the system for spirited listening and not strain an amp or avr?

 

The question remains, is bi-wiring or bi-amping really worth it unless you have extra amps laying around?

[Khornukopia]

1 hour ago, jjptkd said:

 

I'm not sure exactly how the "magic" works but I have tested this numerous times and get the same result each time.

 

I take a standard Sunfire Cinema Grand amplifier rated at 200x5 watts @ 8ohms, 400x5 watts @ 4ohms. I first run the speakers with just two channels, then switch to passively bi-amping with 4 channels from the same amp. The difference is exactly what you'd expect if you doubled the power going to the speakers. It gets louder faster on the volume knob and has higher total output before distorting.

 

In single wire configuration the amp is connected to a nominal 8 ohm speaker load. In bi-wire configuration with a bi-wire compatible passive crossover that has had the jumper straps removed, the amp is more likely connected to 4 ohm loads. Therefore, each channel of your amp IS more powerful in bi-wire mode and you are using twice as many amp channels.

[minermark]

39 minutes ago, Khornukopia said:

 

In single wire configuration the amp is connected to a nominal 8 ohm speaker load. In bi-wire configuration with a bi-wire compatible passive crossover that has had the jumper straps removed, the amp is more likely connected to 4 ohm loads. Therefore, each channel of your amp IS more powerful in bi-wire mode and you are using twice as many amp channels.

Now with that statement, you have what is the FIRST theory of Bi-wire that kind of sounds like real logic.

I run in the Bi-Amp mode, and pizz-off the neighbors just fine.

[derrickdj1]

1 hour ago, Khornukopia said:

 

In single wire configuration the amp is connected to a nominal 8 ohm speaker load. In bi-wire configuration with a bi-wire compatible passive crossover that has had the jumper straps removed, the amp is more likely connected to 4 ohm loads. Therefore, each channel of your amp IS more powerful in bi-wire mode and you are using twice as many amp channels.

The 4 ohm load can provide more watts if needed but the current flow is higher.  If you are in the comfort zone of operation the driver will not get more watts.  With 4 ohms load there is a higher resistance which relates to the higher current flow.

[ATLAudio]

5 hours ago, derrickdj1 said:

I know what you are getting at.  For example if the bass driver needs 50 watts the same signal is being sent to each driver or 100 watts total for the Hi and Lo driver.  Using two amps, each amp in passive bi-amping is responsible for 50 watts.  So, in theory each driver is 3 db louder

 

 The 3 db is only percieved as slightly louder.  To double the percieved volume you need 10X the power.  This is most applicable to a system running the mains as Large and no subwoofer  For example a 1 kHz signal using  1 watt produces 70 db.  Now add a 40 Hz signal that you want to be as loud requires 100 watts.  Add a sub in the picture and XO at 80 Hz and you now need around 11 watts.  See the waste in dynamic headroom running the speakers set to large.

 

Also, running speakers as Large causes more cone movement=more distortion.  The 3 db is not even needed for most listening because the Klipsch speakers are so efficient.  This is why many of us with tube amps and Klipsch are running flea power amp of 4-20 watts.  I run my RF 7 II's off a 40 or 45 watt tube amp for music which is plenty loud.  I also have a 200 watt power amp that I use on the speakers for HT.  Less than 10  watts on the tube amp get me over 100 db with the RF 7 II's ran as Large.

 

Having 300-400 watt amps with most Klipsch speaker is overkill.  All the extra power just goes unused.  If any speaker benefit most from extra amplification is a smaller speaker with lower sensitivity.

 

 

13

I'll try and unpack this suitcase...

 

"The 3 db is only percieved as slightly louder.  To double the percieved volume you need 10X the power.  This is most applicable to a system running the mains as Large and no subwoofer  For example a 1 kHz signal using  1 watt produces 70 db.  Now add a 40 Hz signal that you want to be as loud requires 100 watts.  Add a sub in the picture and XO at 80 Hz and you now need around 11 watts.  See the waste in dynamic headroom running the speakers set to large."

 

Your example speaker, while easier I guess to prove your point with, would be an incredibly awful design. 3dB can be perceived as noticeably louder which increases efficiency and reduces distortion. While using an active crossover (setting to large is Audyssey speak) to an active subwoofer is a fantastic (but in no way necessary) way to allow your main amp to be more efficient, passive bi-amping CAN bring benefit. But, not everyone has, nor wants or even needs to bring subwoofers into the mix.

 

"Also, running speakers as Large causes more cone movement=more distortion." 

 

dafaq? Running a speaker to the point where the amp causes a clip causes distortion harmonics which are to be avoided. Do you think that the cone movement in your active subwoofer doesn't count? 

 

"This is why many of us with tube amps and Klipsch are running flea power amp of 4-20 watts."

 

No, you do this, whether you realize it or not, so that the tube amp is closer to distortion levels and is adding distortion flavor (from the softer clipping characteristics of tubes) which you find pleasing, but is the purest definition of distortion, and inaccuracy. 

 

"I run my RF 7 II's off a 40 or 45 watt tube amp for music which is plenty loud.  I also have a 200 watt power amp that I use on the speakers for HT.  Less than 10  watts on the tube amp get me over 100 db with the RF 7 II's ran as Large."

 

I'm nearly certain that your tube amp is constantly clipping and that this is likely fine, tubes being what they are. Your speakers stated specs have needs of up to 250 watts RMS, and 1000 watts peak, all which could be demanded depending on listening levels. Unused amp sections passively bi-amped would not hurt to be run to both halves of the RF-7, with or without a subwoofer, and potentially see noticeable benefit, YMMV

[derrickdj1]

An easy way to see how much power you are using is everytime you increase the power 10X, add 10 db.  The RF 7 II's is db sensitivity at 1 meter.  It is 111db at 10 watts and 121 db at 100 watts.  I rarely listen to music much above 85 db.  Add a second RF 7 II and another 3 db. is gained.  In the small home the spl is even more intense than outdoor or a large concert hall. 

 

Now there will be loss of spl related to distance.  Using my 40 watt amp here are calculations from a spl calculator. http://myhometheater.homestead.com/splcalculator.html  Sensitivity 101 db, amp power 40 watts, distance 12 ft, 2 speakers, gain from amp 16 db, room loss -11.3 db, wall reinforcement 3 db, reflection in small room 3 db., and finally spl at MLP 118 db.

SPL CALCULATOR
Speaker Sensitivity:	101 dB SPL (1 W/1 M)
Amplifier Power:	40 Watts
Distance:	12 feet
No. of Speakers:	2 usually 2, more for multi-channel
Speaker Placement (Choose 1):	Away from walls (or do not consider placement)
	Near a wall (within 2 to 4 feet)
	In a corner (within 18 to 24 inches)

RESULTS
16	dB Gain from amplifier
-11.3	dB Loss due to dispersion (distance)
3	dB Gain from sonic reinforcement (multi speakers)
3	db Gain from placement (reinforcement from reflected sound)
118	dB SPL at listening postion

[derrickdj1]

The table above is very light but, the final spl at an average listening distance of 12 ft. is 118 db with the 40 watt tube amp.  Not much clipping going on.  Use a larger amp and there will be more gain.  People can do as they like but, for me, I try to understand what exactly I'm doing.  Even with big 200 watt amps, you are only getting an extra 3 db over a 100 watt amp/avr.  Certainly not enough to write home about.

[Don Richard]

13 hours ago, Khornukopia said:

 

In single wire configuration the amp is connected to a nominal 8 ohm speaker load. In bi-wire configuration with a bi-wire compatible passive crossover that has had the jumper straps removed, the amp is more likely connected to 4 ohm loads. Therefore, each channel of your amp IS more powerful in bi-wire mode and you are using twice as many amp channels.

 

BULLSHIT!!!!!!!!

[derrickdj1]

Passive bi-amping is also know as fool's bi-amping for a reason.

[Schu]

^I'll let you know, because I am going to try it 

[ATLAudio]

2 minutes ago, derrickdj1 said:

Passive bi-amping is also know as fool's bi-amping for a reason.

The gains from passive bi amping are modest, but measureable, and depending on your set up, quite noticeable, or completely undetectable. Dismissing it as fools bi amping is obtuse to say they least. If you have unused amp stages and extra speaker wire hanging around, why not experiment with a relatively free mod? We're not talking about exotic priced wires or such.

 

Moreover, I don't see the point in coming up with a situation to paint it in the worst possible light that's not relevant to someone else's set up.

[wvu80]

19 hours ago, derrickdj1 said:

I know what you are getting at.  For example if the bass driver needs 50 watts...(respectful Snip!, I just wanted to reference your post)

Excellent post.  That is the best description explaining the WHY that I've ever heard. 

[ATLAudio]

20 hours ago, Khornukopia said:

 

In single wire configuration the amp is connected to a nominal 8 ohm speaker load. In bi-wire configuration with a bi-wire compatible passive crossover that has had the jumper straps removed, the amp is more likely connected to 4 ohm loads. Therefore, each channel of your amp IS more powerful in bi-wire mode and you are using twice as many amp channels.

 

 

No, bi-wiring does not turn your speaker into a series.

[dtr20]

I still want someone to bi amp using a tube amp for the mid to highs and ss for bass. Then report back

[jjptkd]

2 hours ago, derrickdj1 said:

Passive bi-amping is also know as fool's bi-amping for a reason.

 

Calling people names does not make your point any more legitimate. There is in fact many ways in which passively bi-amping can improve ones situation, it should not to be written off as junk science or snake oil like bi-wiring. It may not be good for you in your situation but that does not mean it would not be helpful for someone else.

[jjptkd]

I found this article referencing "fools bi-amping," note the highlighted section.

 

http://www.chuckhawks.com/bi-wire_bi-amp.htm

 

"Passive bi-amping

Passive bi-amping (also known as "fools bi-amping" for good reason) requires loudspeakers with the dual binding posts used for bi-wiring, again with the shorting bar removed. The difference (and profit advantage for the retailer) is that it requires two stereo power amplifiers, instead of one, and an additional pair of speaker cables. (Can you guess who is getting fooled by passive bi-amping?)

In passive bi-amping, the output from the pre-amplifier is fed to a pair of identical stereo power amps. All four amplifier channels are fed the same, full range, signal from the pre-amp. This is important, so take note of it. The output of the power amps is fed to the stereo loudspeakers, the left and right outputs of one power amp to the left and right loudspeakers' high frequency binding posts and the left and right outputs of the other power amp to the left and right loudspeakers' low frequency binding posts. We now have the same, full range signal everywhere. The high frequency part of each loudspeaker's passive internal crossover is doing what it always does with a full range signal, as is the low frequency part of each loudspeaker's crossover.

From the listener's perspective, if all goes well, the sound quality should remain exactly the same. However, the placebo effect insures that most folks who passively bi-amp their music systems report a sonic improvement. The system's total amplifier power has been doubled, which is probably a good thing and may actually result in a sonic improvement at high listening levels. However, if doubling the system's amplifier power is necessary, it would be cheaper to buy (for example) one 200 watt stereo amplifier than two 100 watt stereo power amps of the same quality to get the same result."

 

 

This is what I have found to be true as stated in my first post. Obviously whether or not the extra power is needed or to what degree it will help will vary on a case by case scenario.

[Schu]

3 hours ago, dtr20 said:

I still want someone to bi amp using a tube amp for the mid to highs and ss for bass. Then report back

That will be me, because in another week I have some time. I am going to try a tube top end and a class d bottom. Ever since going all tube, I have noticed a BIG difference (lacking) in the low frequencies over what had been spectacular with my class d/tube pre set up.

 

That article above specifically states the same model amplifier... to me that does sound foolish.