Benefits of bi amping ??

[crome]

Hi folks

I have a Marantze PM-15 S2 integrated amp running at 90 wpc. I have some questions if any knowledgable souls have an answer please.

These amps are capable of being bi amped (up to 4 decks) and have F.C.B.S. in/out jacks for synchronising the decks with a facility to designate the master amp etc. If just using 2 decks in bi amp mode each obviously acts as a monaural and each amp supplies 1 speaker allowing for bi wiring of speakers which is not available when using a single amp (unlike my Linn). The analogue output from the cd player etc is also split between amps.

My questions are these:

Will adding a second amp and bi amping them really make enough of a difference to justify the cost of a second amp? How would it change the characteristics?

The amp is 90 wpc dose this double when bi amping? What i mean by this is I assume that a 90 wpc amp is essentially 180 w total shared between 2 speakers, therefor am I correct in thinking when bi amping I would get 180 wpc ?

Thanks in advance guys

[shadowlord]

I'm not sure if i understand correctly but i think you confuse bi-amping with bi-wiring.

bi-amping= usign 2 seperate stereo amps. 1 for the low frequencies and one for the highs.

bi-wiring= using 1 stereo amp. but wire the low frequency input of the speakers to speaker output A. And wire speaker output B to the input for the highs on the speakers.

[LesX55]

Hi,
Shadowlord is correct with his definitions.

Can not say how good bi-amping will be ( though a am sure it would bring benefits ),i can however tell you that bi-wiring suitable speakers makeS for a amazing improvement.

I use an AVI Lab Series S21, with Townshend Isolda Speaker cable ( bi-wire )with my Castle Howards S2....

[crome]

Thanks for quick response guys, I didnt really explain myself too well.

I'm basically asking if there are any noticeable benefits to bi amping ie using 2 amps together. As I mentioned my Marantze amp is capable of doing so and has sycronising outputs to further enhance this process.

Where I have confused things is mentioning bi wiring. This amp on its own is not capable of bi wiring the speakers and only has single outputs per channel (unlike my Linn). However my manual shows a configuration where this is possible when another identical amp is paired up in a bi amp configuration. There are switches on the back that you select if bi amping and this alters the speaker outputs. Each amp supplies 1 speaker but you now have 4 speaker outputs allowing bi wiring. Im totally new to this arrangement of bi amping. The fact that this facility is available on these amps suggests that there must be a reason why it would be done but Im trying to ascertain how much of an improvement there would be verses using a single amp as there is the cost of a second amp to consider.

Im also enquiring if bi amping will double the available wattage to the speakers?

I'm running Mission 796's btw. Cheers

[speakerman1]

Bi-amping can be done 2 ways. Running each speaker with one amp each or if your speakers are wired for it you can run your tweeters with one amp and your woofers with one amp.

If you put 90 wpc in that is what you will get is 90 wpc unless it is done in series. A single 90 wpc amp is pushing 90 wpc. If you have 2 amps they are still pushing 90 wpc.

Bi-wiring. My bi-wires are all on the A side then split at the speaker. I got better bass response by doing this.

When I built speakers and they were wired for bi-amping. Each speaker had a different and separate xover and was jumpered outside on the terminals.

It is kind of an expensive experiment to see if biamping helps. I used Marantz mono-blocks to do my biamping. Good amps for the money. So I was doing pure biamping.

Larry

[Socal Sam]

Assuming your speakers are bi-amp capable, always bi-amp with a second amp of the same model. Wire them laterally so that one amp drives only the upper and the other amp drives only the lower. This reduces cross talk.

Benefits: Bi-amping doubles the power available for each half of the speaker. This means more power in reserve which reduces compression from power sag when driving hard. I think disconnecting the upper and lower drivers makes them less resistive overall which also has benefits for dynamics.

Bi-wire is a waste of time, IMO.

[crome]

Assuming your speakers are bi-amp capable, always bi-amp with a second amp of the same model. Wire them laterally so that one amp drives only the upper and the other amp drives only the lower. This reduces cross talk.

Benefits: Bi-amping doubles the power available for each half of the speaker. This means more power in reserve which reduces compression from power sag when driving hard. I think disconnecting the upper and lower drivers makes them less resistive overall which also has benefits for dynamics.

Bi-wire is a waste of time, IMO.

Hi my Missions are not bi amp capable only bi wirable. Why do you feel bi wire is a waste of time? I'm not really sure what bi wiring means on a speaker other than there are 2 pairs of cables connecting amp and speaker.

However what I'm trying to ascertain with the amp I have is what if any benefit would I gain from purchasing another identical amp and bi amping them. This particular amp has been designed to be bi amped and as mentioned has synchronising in/out jacks and various settings to pair them up. This then according to the manual alters the speaker outputs allowing bi wiring which isn't available when only using 1 amp on its own.

[Web Police]

Hi my Missions are not bi amp capable only bi wirable.

If your speakers are bi-wireable then they probably have two sets of inputs with a strap between them? If this is the case you should be able to remove the straps and then use separate amps for the high/mid and low frequencies.

I'd say try bi wiring and if it improves the sound go with it. As far as bi-amping and bi-wiring you are the only one that can judge whether or not it would be worth it. Bi-wiring will most likely be a lot cheaper then bi-amping. In my mind you might notice the effects of bi-amping, but I am not sure about bi-wiring.*scratchchin*

[crome]

If your speakers are bi-wireable then they probably have two sets of inputs with a strap between them? If this is the case you should be able to remove the straps and then use separate amps for the high/mid and low frequencies.

I'd say try bi wiring and if it improves the sound go with it. As far as bi-amping and bi-wiring you are the only one that can judge whether or not it would be worth it. Bi-wiring will most likely be a lot cheaper then bi-amping. In my mind you might notice the effects of bi-amping, but I am not sure about bi-wiring.*scratchchin*

Many thanks for every ones input. I need to correct my last post after reading the speaker manual as these missions are both bi wirable and bi amp capable

[shadowlord]

if you can bi-amp within your budget i say do it.

[Des-Lab]

Oh if I could only find something decent with lots of power *and* three tape loops. That is the one relatively weak link in my system: the heart. It's a 60 watt p/c Circuit City vintage Kenwood. I mean it's ok, but hardly worth bragging about. But it was the only thing I could find that had the requisite three tape loops that I needed to run my system. Everything else I've seen either has only two or just one. Any suggestions?

[speakerman1]

I have a DBX 400 with 3 tape loops. That is how I get my all my decks in my system. I just have to hook it up again.

Larry

[Socal Sam]

Hi my Missions are not bi amp capable only bi wirable. Why do you feel bi wire is a waste of time? I'm not really sure what bi wiring means on a speaker other than there are 2 pairs of cables connecting amp and speaker.

However what I'm trying to ascertain with the amp I have is what if any benefit would I gain from purchasing another identical amp and bi amping them. This particular amp has been designed to be bi amped and as mentioned has synchronising in/out jacks and various settings to pair them up. This then according to the manual alters the speaker outputs allowing bi wiring which isn't available when only using 1 amp on its own.

Bi-wire is using the SAME amp to drive your speakers. You would use the A and the B outputs to drive each half of your speaker. This does not increase the power potential of your system so there are no discernible benefits. Hence, a waste of time, IMO.

[laatsch55]

And to BI/ TRI amp you require an active electronic crossover, ala, Pioneer D-23, SF-850. Behringer makes several that good And a very good understanding on Cut out/ Cut out freq, Db/ octave rolloff etc.
A very good tutorial on bi-amping can be had at Elliot Sound Products. Google that and check out his feelings on bi-amping. Should be stock reading for anybody considering this.

[speakerman1]

And to BI/ TRI amp you require an active electronic crossover, ala, Pioneer D-23, SF-850. Behringer makes several that good And a very good understanding on Cut out/ Cut out freq, Db/ octave rolloff etc.
A very good tutorial on bi-amping can be had at Elliot Sound Products. Google that and check out his feelings on bi-amping. Should be stock reading for anybody considering this.

HUH? Why do you need an external cross over. If the speakers were designed for biamping they have separate xovers inside all ready. Why the need for external. I see no reasoning for this at all.

My advice is to borrow an amp from someone and try it. Try bi-amping both ways. Run 1 speaker with one amp and the other speaker with the other amp. and then run your woofers with one and your tweeters with another. There is no need for external xovers. If you want you can PM me. I was building and bi-amping speakers in the early 90s. I had good results. I just tried by wiring last year. I opened up the bass on my speakers. It was very noticable. I run my bi-wires off of my A side. There are 2 RCAs at the amp and 4 RCAs at the speaker. I run my woofers with one pair and mt tweeter and mid with the other pair. Both of my Epos are bi-wired. I like it. If I didn't hear a difference. I wouldn't have sold my Audio Magic cables. I'm running Tara Lab Bi-wires now. They are about 1/2 inch to 3/4 inch in diameter.

Larry

[A.N.T.]

Bi-wire is using the SAME amp to drive your speakers. You would use the A and the B outputs to drive each half of your speaker. This does not increase the power potential of your system so there are no discernible benefits. Hence, a waste of time, IMO.

There are sonic improvements from bi-wiring, thought how much a particular setup would benefit from it depends on many things. The physics of bi-wiring is simple enough - the speaker is not a linear device, each driver produces not only sound but distortion too. As a result the current through each driver is distorted. If you have a single pair of wires to connect both drivers to the amplifier then the distortion from the woofer will get to the tweeter more readily than with bi-wiring. This is especially noticeable for speakers with very simple crossovers - like mine Epos M-12 or Larry's Epos M12.2 .

Alex

[Socal Sam]

There are sonic improvements from bi-wiring, thought how much a particular setup would benefit from it depends on many things. The physics of bi-wiring is simple enough - the speaker is not a linear device, each driver produces not only sound but distortion too. As a result the current through each driver is distorted. If you have a single pair of wires to connect both drivers to the amplifier then the distortion from the woofer will get to the tweeter more readily than with bi-wiring. This is especially noticeable for speakers with very simple crossovers - like mine Epos M-12 or Larry's Epos M12.2 .

Alex

If you are trying to improve separation by lateral bi-wire, say running the upper drivers with one channel and the lower drivers with the other channel, you might get some benefits in the mids and highs. However, driving both woofers from the same channel will increase likelihood of power sag which you will hear as compression. IMO, bi-wire doesn't deliver. Only additional power through bi-amping will make a significant difference.

[laatsch55]

Larry, an external crossover lets you select the cutoff freq and slope of rolloff, much better control of the dividing process.

[Socal Sam]

Larry, an external crossover lets you select the cutoff freq and slope of rolloff, much better control of the dividing process.

Wouldn't flatting roll off be better served with an EQ?

[laatsch55]

No Sam, as crossovers are high and lo cut filters theres a wee bit more to it. Rolloff is expressed as decibels per octave, or how fast the signal that is filtered is attenuated. If you have an electronic x-over in a tri-amp situation switching between 6 and 18 db is an eye opener. First time I played with it my first thought was a cheap speaker crossover has probably condemned a lot of speakers over the years.

[speakerman1]

No Sam, as crossovers are high and lo cut filters theres a wee bit more to it. Rolloff is expressed as decibels per octave, or how fast the signal that is filtered is attenuated. If you have an electronic x-over in a tri-amp situation switching between 6 and 18 db is an eye opener. First time I played with it my first thought was a cheap speaker crossover has probably condemned a lot of speakers over the years.

What do you classify as cheap? A well designed xover will give your speakers the right xover points and your roll off. I'm more in belief that less is better. I can make a speaker sing without any fancy xover. Just a 1st order. If everything is done right your points and everything will be just right.

Larry

[Socal Sam]

No Sam, as crossovers are high and lo cut filters theres a wee bit more to it. Rolloff is expressed as decibels per octave, or how fast the signal that is filtered is attenuated. If you have an electronic x-over in a tri-amp situation switching between 6 and 18 db is an eye opener. First time I played with it my first thought was a cheap speaker crossover has probably condemned a lot of speakers over the years.

In theory, the filters in better passive crossovers are suppose to be brick walls. I agree with speakerman, simplicity is the key (to all audio). You would have to bypass the internal crossover with an external active. Then, you would have to second guess the speaker designers and their measuring equipment with your ears. It is not clear what your proposed setup is.

[laatsch55]

Speakerman 1, Socal Sam, I agree less is better. Al Klappenberger is a designer and builder of world class passive x-overs, his "Universal" model for the K-Horns is a game changer, all quantified with every test imaginable, except anechoic chamber. A first class passive such as his don't leave much room for improvement. That said, when changing drivers in my K-horns I like to tri-amp to see if the passive treats the new drivers as the old ones, some minor value changes in the caps and different tap settings on the mid horn autotransformer are all that I've needed to address. Then there are the intriguing possibilities of tubes driving the mids and tweets while the SS handles the low ends. As every listening enviroment is different it's another tool to conform the equipment to the space. Being able to control the LEVEL of each driver is also a plus.
" Cheap" crossovers, was refering to some companies tendencies to go cheap on the passive components. Not all caps sound the same as you both know.
Lee

[speakerman1]

In my xovers. I didn't have a computer to design them for me. I did it the old fashion way. I used 14 ga. goertz flat wire and their air core inductors I forget which name brand of caps ; but they were the self healing polypropylene. Back then they weren't cheap. It took awhile for me to pick my drivers and figure where I want to xover. It was a work of joy. Once everything was figured out. I would start to build. All the xovers were hard wired. I loved building speakers. After building them and hearing the 1st notes come through them I would just smile. I always used a Morel tweeter. The silk dome and they were so fast. To me they couldn't be beat.

Larry

[laatsch55]

Larry, you talk of speaker building like I do about fly tying, you thoroughly enjoy it. That's way cool.

[2ndRick]

HUH? Why do you need an external cross over. If the speakers were designed for biamping they have separate xovers inside all ready. Why the need for external. I see no reasoning for this at all.

The best reasoning for a true bi-amp is to tailor the sound to extract the absolute best performance from your multiple driver speakers. Additionally, you remove the compromises of the passive devices.

I saw your later post about hand selecting passive components like Goertz air core coils and mylar or poly caps. Yes, they are significant imrovements over the gabage electrolytics and inferior coils in a lot of lower budget commercial products, but the fact remains that ANY passive components in the signal parth will absorb power, and cause phase shift.

That is still not the primary reason. The primary reason is tuning flexibility and headroom. When you have a dedicated amp channel for each driver in each frequency range, the system will have much more headroom because the delicate tweeter is not connected to the amp channel which may be driven into clipping in the lower frequency range.

I saw someone mention Behringer... I wouldn't use a Behringer anything. They are the equiv. of Kraco, Soundesign or Yorx in prosound. Also, many of their designs are in lawsuits because they are blatant copies of units with patented technologies from leaders like QSC, Rane, BSS, etc. If/when they are removed from the market, service may be an issue. Considering the compromises in build quality needed to achieve those low price points, it's not a gamble I would take. :)

QSC and BSS SoundWeb are the finest in the range for DSP devices where you can add filters such as multiple bands of parametric EQ and limiters in addition to flexible crossovers with a variety of slopes to choose from.

Obviously a DSP means that the signal goes through an A/D conversion at input, and a D/A conversion at output. A lot of analog purists will not accept this, no matter the incredible flexibility the DSP realm can provide. Well known companies like Rane and Bryston are excellent choices if you want to stay in the analog domain.

[2ndRick]

Back to custom tailoring:
With active crossovers, a minor shift in frequency set point between mid and tweeter is a knob turn away. Same with relative level between drivers.

No more impedance correction networks with ceramic resistors, no more ordering piles of caps and coils to build in bread boards for 'voicing'.

Most speaker manufacturers will use active crossovers to voice their speakers. They determine the best xover slope, the best xover points, whether symmetrical or asymmetrical would be best, and then set the levels to match the output of the different drivers at the crossover point so there is a seamless handoff.

Once a speaker is voiced, they calculate the values of the passive devices required to achieve the chosen criteria in the xover network, build bread board samples, and compare them to the fully active test model in listening and measurements.

===========

Even taking the tuning out of the equation, to say that a good passive crossover is just as good as an active setup is to say that you have the same clarity looking through a window with several layers of sheer draperies as I have when viewing directly out the wide open front door. I don't care if that material is really, really sheer, there are losses and distortions compared to not having them there at all. Passive components after the amp are the same way.

The best thing to do is to open the speaker cabinets and hardwire speaker wire directly from the input cups to the drivers, and remove the passive crossovers.

NOTE:
If you send low frequencies into a tweeter, it will have a very very short life. Have your crossover setup before you power up your amps, and always start at a ridiculously low listening level to verify that the correct frequency ranges are being directed to the right drivers before adding any volume.

===========

One last thing. Vertical bi-amping.
Crosstalk is a channel to channel thing, so the best method of implementing two identical amps on a 2-way speaker is to use one amp for one speaker. Say Left channel is lows, and right channel is highs (or vice versa). That way the right channel will not bleed into the left because there is no right channel information of any kind in that chassis.