leftwinger57 Posted April 26, 2011 Share Posted April 26, 2011 HI GUYS ,I guess this is an observation of the practice of bi-amping, mono blocks and biwireing I guess I'm one jealous guy when I see someone use two amplifiers to seperate the tweeters from the woofers.How does this inprove on the sound . Now about mono blocks I once spoke to an engineer at MacIntosh and never heard of taking two mono amps to create stereo I asked him why. His answer and he was quite serious is when you could afford such things ,,that's what you do and besides it looks cool. I've now learned that seperating the power sources on different chassis produces the most clarified sound one could get. Is bi-wireing of speakers that are able to do this the way to go. It seems to me many amps to do the same thing, get sound out of a speaker......LW Quote Link to comment Share on other sites More sharing options...
Don Richard Posted April 26, 2011 Share Posted April 26, 2011 If you intend to biamp you need to use an active or line level crossover ahead of the two amps. Running two amps and using the crossover in the speaker just costs $$ with no upside. Quote Link to comment Share on other sites More sharing options...
vnzbd Posted April 26, 2011 Share Posted April 26, 2011 I think the experts here would all agree that active bi-amping would be the way to go with an external electronic x-over. I have been doing that with car stereo for years and can attest to the superior sound in that market. I will say that passive by-amping could also have its merits. There are some on this forum that will use tube amps for the highs and solid state on the lows. I do passive bi-amping and attenuate the highs to "rebalance" the speaker. If your speaker is going to suck up the juice on the bass heavy notes, passive bi-amping can clean up the mids and highs during the bass peaks. Quote Link to comment Share on other sites More sharing options...
djk Posted April 27, 2011 Share Posted April 27, 2011 " If your speaker is going to suck up the juice on the bass heavy notes, passive bi-amping can clean up the mids and highs during the bass peaks." Please explain that in great detail. If I have a 100W SS amp on the bass and a 25W tube amp on the highs and attenuate the highs 3dB lower than what the speaker was designed for, then the HF amplifier still clips at levels well below where the LF amplifier does. http://db.audioasylum.com/mhtml/m.html?forum=speakers&n=138657&highlight=cornwall+djk&r=&search_url=%2Fcgi%2Fsearch.mpl%3Fforum%3Dhug%26searchtext%3DM4%2Bdjk Quote Link to comment Share on other sites More sharing options...
vnzbd Posted April 27, 2011 Share Posted April 27, 2011 It is typically the bass that requires/uses the lions share of an amplifier. The highs and mids do not have to move the mass assocaited with the woofer, meaning it is easier on the amplifier on the high/mids. As you have stated in your system the highs and lows are run on different wattage amplifiers and going just by the numbers it appears that the lows require more power to keep up with the upper end. As some people smarter than I will say a watt does not always equal a watt, and it varies from manufacturer to manufacturer how their specs are arrived at. With my Chorus IIs it takes considerably more clean/high current watts to have the bass balanced with the highs at the volumes I currently listen at(medium). When I passive bi-amped my setup(also with 3db cut on the highs) not only did the bass come alive(or appeared to with the attenuation of the highs), the highs also seemed to improve. By running the highs on a seperate amp channel than the bass, they do not see the large current draw placed on the amp of the bass channel. Where they do not require the current that is sucked up by the low end, they do not have to deal with the current draw of the bass, thinning the power delivered to them. Clean in, clean out. Quote Link to comment Share on other sites More sharing options...
Don Richard Posted April 27, 2011 Share Posted April 27, 2011 As some people smarter than I will say a watt does not always equal a watt, and it varies from manufacturer to manufacturer how their specs are arrived at. A watt equals voltage X current everywhere you go all of the time. In the US the FTC mandates a standard for rating home stereo amplification equipment because of unrealistic ratings from some manufacturers in the past. Note this does not apply to autosound, home theater, or pro sound gear, however. The FTC method requires an hour at 1/3 power preconditioning before measuring. The manufacturer must state the frequency range and distortion at rated power, and that the power delivery is continuous with both channels driven. Of course that isn't the whole story. There's also current capability, input impedance, output impedance, overload recovery time, and distortion spectrum for starters. But none of those things define power output. Quote Link to comment Share on other sites More sharing options...
vnzbd Posted April 27, 2011 Share Posted April 27, 2011 I agree with what you have said Don, a watt is a watt when talking about power. What I mean is a watt is not always a what is when the spec is in to 6 ohms vs 8 ohms, when the spec is a 1khz vs 20-20khz, and so on. I know that AC is much more complex than DC but how is the watt delivered. For simplicity sake, look at a DC watts, as you have referenced. Power = Voltage x Current, or P=IE. 50 volts x 2 amps = 100 watts, 10 volts x 10 amps = 100 watts. Power equal yes, but two different ways to get there. I feel that all watt or power does not always sound the same. Tube vs solid state? Older HK vs Sony? Does the FTC regulate avr's now when one states 125 watts x 7. There are plenty that advertise it but how many deliever? As you have also stated there are other factors involved. These follow much more of the AC theory and impeadance vs resitance. Most avr's will not have the headroom of a dedicated amp. Both can have the same FTC rating but deliver quite different under a demanding load. So I do agree a watt is a watt everywhere you go all of the time for electronic test gear, but the ears, maybe not so much! Quote Link to comment Share on other sites More sharing options...
djk Posted April 27, 2011 Share Posted April 27, 2011 "It is typically the bass that requires/uses the lions share of an amplifier." Again, Please explain that in great detail. How can the HF amplifier keep up without a filter to remove the bass? That is why we call what you're doing 'fool's bi-amping'. Quote Link to comment Share on other sites More sharing options...
DrWho Posted April 27, 2011 Share Posted April 27, 2011 What speakers are you running? Quote Link to comment Share on other sites More sharing options...
Guest " " Posted April 27, 2011 Share Posted April 27, 2011 We are getting confused.....as often happens.....using an active crossover is not the only way to bi-amp...AND....I don't think we are clear in this discussion what passive crossover options are available...there are two types of passives...one is a high level one which is placed between the amplifier and the drivers.....the other is a low level one which is placed between the signal source and the inputs of an amplifier......so for example...from memory...assume 600ohm input impedance...a low level passive crossover would consists of a .07 cap before the input of the amp for the tweeter.....a .7 cap in series with a 25mh inductor in front of the input for the mid driver amp...and a 200mh inductor infrom of the input of the woofer amp.....that would give you a passive line level crossover which would seperate signals so that each of the three amps can amplify only a portion of the sound spectrum....SO...you don't necessarily need an active crossover to do this. The F-MOD line of signal filters is a cheap whay of doing this...they use resistors and caps instead of caps and inductors. Quote Link to comment Share on other sites More sharing options...
vnzbd Posted April 27, 2011 Share Posted April 27, 2011 As I stated earlier, there are many here on the forum that are smarter than I! It is in my humble opinion that the bass is where the majority of power is needed. If you seperate the lows and highs of different amplifier channels, even without an F-mod, Then you have two distinct amplifiers driving two distinct sections. While I passive bi-amp, using the internal speaker x-over and therefore send the entire range of frequencies to both sections, the high pass portion of the x-over dumps the lower freqs, the mid and tweeter do not try to produce the bass freqs, therefore the high pass amp does not feel the current surge that the lowpass amp feels. I do use a 5 channel amp and so I am sure that the current drain does hit the shared power supply but based on the amps ratings it should have less effect than running it all on the same amp channel. Both channels of the amp to each speakers are rated at 200wpc and I know that the speaker is now not seeing 400 watts, it is still seeing 200 per section. That is about as much detail as I can provide based on my knowledge and experience. Is it fools bi-amping, maybe. But I will trust my ears and the difference I have made in my system, again using a 3db f-mod attenuator on the highs. Quote Link to comment Share on other sites More sharing options...
Guest " " Posted April 27, 2011 Share Posted April 27, 2011 vnzbd I understand exactly what you are doing.....but to clarify....the crossovers are not dumping out of band material...they are blocking it at the cross over slope rate....if you look at the blue line...it gives a sense as to what that would look like.....as the impedance goes up...the amp becomes less efficient at out of band material....relative to remaining efficient producing in band material. Quote Link to comment Share on other sites More sharing options...
Guest " " Posted April 27, 2011 Share Posted April 27, 2011 standard passive bi-amping Quote Link to comment Share on other sites More sharing options...
Guest " " Posted April 27, 2011 Share Posted April 27, 2011 vertical passive bi-amping Quote Link to comment Share on other sites More sharing options...
vnzbd Posted April 28, 2011 Share Posted April 28, 2011 speakerfritz, It has been quite a while(25+ years) since electronics school! We did not really dive into speaker x-overs per say but I do recall hi pass, low pass and band pass circuits being discussed. The concept of blocking the freqs does sound familar! I am looking at the two versions of bi-amping and Believe that I am somewhere in the middle. Since I use a 5 channel amp(1 channel for the center), I do not have a specific L/R amp or a High/Low amp. I come straight out of the pre-amp with y cable on both the L&R out into the 5 ch amp. I do use and -3db attenuator at this stage on the highs. Ch1-L lows, Ch2-L highs, Ch3- center, Ch4-R highs, Ch5-R lows. Based on that what type of bi-amp set up would tyou say that I have? Thanks! Quote Link to comment Share on other sites More sharing options...
djk Posted April 28, 2011 Share Posted April 28, 2011 If you don't have a dividing network ahead of the amplifiers, you're using the fools bi-amping method. Quote Link to comment Share on other sites More sharing options...
Guest " " Posted April 28, 2011 Share Posted April 28, 2011 Based on that what type of bi-amp set up would tyou say that I have? since the amp channels connected to both the HF and LF section in one speaker system share the same power supply, I would put it at vertical bi-ampling. In a standard passive, the LF for both speakers share the same power supply while the HF for both speakers share the same (while different from the LF shared power supply) power supply. Some multi channel amps have independent power supplies, but most have a single shared on. That is what you need to find out about your amp....does it have 5 independent power supplies or 1 shared one. Quote Link to comment Share on other sites More sharing options...
vnzbd Posted April 28, 2011 Share Posted April 28, 2011 speakerfritz, The amp that I use is the Emotiva XPA-5. It has a single power supply with 5 "amplifier cards". 200WPC @ 8ohms, 20-20k, all channels driven. Emotiva has stated that in 2 channel use its specs are closer to 300WPC but being a 5 channel amp they do not advertise that spec as it is not its intended use. Based on the shared power supply would you then say verticle bi-amping? Thanks for the education! djk, Fools bi-amping? Please explain that in great detail. Quote Link to comment Share on other sites More sharing options...
Guest " " Posted April 28, 2011 Share Posted April 28, 2011 yep....vertical all the way Quote Link to comment Share on other sites More sharing options...
Don Richard Posted April 28, 2011 Share Posted April 28, 2011 I agree with what you have said Don, a watt is a watt when talking about power. What I mean is a watt is not always a what is when the spec is in to 6 ohms vs 8 ohms, when the spec is a 1khz vs 20-20khz, and so on. I know that AC is much more complex than DC but how is the watt delivered. For simplicity sake, look at a DC watts, as you have referenced. Power = Voltage x Current, or P=IE. 50 volts x 2 amps = 100 watts, 10 volts x 10 amps = 100 watts. Power equal yes, but two different ways to get there. Power equals volts X amps for AC or DC. With AC if voltage and amps are out of phase the E and I are measured at the same point in time for computing watts (power factor). With an amplifier you are modulating DC and delivering that into the load so power factor does not come into play at that point. The amplifier multiplies the input voltage times it's gain to arrive at an output voltage. Power is determined by squaring that voltage and dividing by the loudspeaker impedance. There cannot be different voltages causing more or less power delivery unless the input signal causes it. I feel that all watt or power does not always sound the same. Tube vs solid state? Older HK vs Sony? Tube amplifiers distort more gradually than most solid state designs, so you can get more than rated power from tubes without reaching audible levels of distortion. Different manufacturers design their amplifiers with differing amounts of headroom. Some amplifiers can deliver twice their rated power during transients, such as when playing music. Does the FTC regulate avr's now when one states 125 watts x 7. No, not as far as I know. So I do agree a watt is a watt everywhere you go all of the time for electronic test gear, but the ears, maybe not so much! Are we talking audio or electroshock therapy here? [] Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.