To bi-amp, or not to bi-amp, ...

Paul, in my case it would be a decent poweramp, as I dont need a pre-amp. I suppose I could get one for each speaker!

Steve, I wasn't supposing addition, rather 'substraction' in the sense that 'should each driver have a dedicated amp', accepting that these ought to have the same gain/tone.

Shrink has just let me know of a HiFi+ article that reviews the Flying Moles, as it happens using the epos es22, so I'll try to get hold of that (I'll accept scanned pages .. without recourse to rights holders!)

 

..and an active crossover between pre-amp and power amps (and bypass or rip out the existing loudspeaker crossovers! )

 

do I detect irony/sarcasm? Its not understood.

I'm just trying to reconcile having a pair of speakers that have been designed to be bi/tri-amp'd, and a weight of opinion that its better to avoid bi-amping.

 

Anytime I've tried bi-amping the result has been impressive, improving imaging and presence in the music.

I don't think you should go by the opinions but try it for yourself. You might get good results using two amps rather than one, you might get better results with one amp that costs as much as both those amps combined.

I thought you had already tried this with the audiolab and flying mole amps and been happy with the results? In which case why are others' opinions so important - opinions which may not be based on as much experience as yours and in fact might just be sheer curmudgeonliness?

 

Hi Alan, I guess its a classic case of swithering! though that's not stopping me enjoying both present listening and some abstract reasoning.

I certainly have enjoyed the AL/FM experiment, and would like to try a bi-amp pair of the same gain/tone. nearest I have got to that was the AL 8000S + 2x 8000M which was impressive - as a result I almost bought a pair of tag 125m.

makes for a lot of boxes though. which made me wonder about using two (three) stereo amps rather than four (six) mono's. And as you know, I've always heard the difference a more watts than the 8000S' 60w, even if I've not been persuaded of SQ/£ (vfm).

I think what I am coming round to is settle on a stereo poweramp that is good upgrade on the 8000S with a view to trying out another of the same type for bi-amping at some stage. that includes the Tact sda as a candidate. I also sent an email to williamhart to demo a jhl amp but no reply.

I revived the thread as the epos es22 was so clearly designed for bi/tri amping.

 

I used to bi amp (passively) and it made a difference as alanbeeb suggested, nut I got better gains with a better poweramp, as alan said you have tried it, and liked it, now try and audition a better poweramp and see what you prefer.

I seem to remember the flying mole epos review, they reckoned they were fine at low volume but lost the plot as things got louder or busier.

 

Rather than buy an equivalent to my present (power)amp, and bi-amp, I do plan to get a better poweramp - but, as indicated, I may then get the same again and bi-amp.

thanks for the recall on the Moles.

 

Sorry ditton, no sarcasm meant – I just couldn't be bothered with a more expanded answer at the time.

At least 50% of the benefit of bi-amping comes with the removal (or by-passing) of the loudspeaker crossovers. Loudspeaker crossovers sap power and introduce various phase distortions - removing them from the audio chain is always going to be beneficial.

To do this requires an active crossover between pre-amp and power amps such that each amplifier only amplifies one part of the audio range (low, mid or high frequencies) with output directly coupled to appropriate loudspeaker drivers.

In all other configurations (psuedo bi-amping, passive bi-amping call it what you will) each amplifier will continue to amplify the full audio range meaning the benefits don't necessarily justify the additional expenditure. Indeed the benefits are debatable much like bi-wiring.

If you are going to bi-amp then take the bull by the horns and do it properly!

All IMHO

 

thanks. I appreciate the time taken to expand the explanation.

From what I can glean, this design has already wrested the bull to the ground, see http://www.epos-acoustics.com/old_products/es22.htm
where there is reference to the particular crossover config. of these speakers.

 

dont know if anyone remembers reading what hi-fi around the late 90's.

an audiolab 8000a, now that would get you started.
next up was to add an 8000p.
this is good, but for best results next change the 8000a for the 8000c pre-amp.
now, change the 8000p for a pair of 8000m monoblocks.
now, buy another two 8000m monoblocks.
congratulations sir, you have the bi-amping what hi-fi review rig.

I remember shop salesmen not being able to sell speakers with just one set of outputs, and everybody buying bi-wire cable, even if they were joining the ends together.

Fashion changed, and now nobody seems to reccomend bi-wiring and bi-amping anymore.

I bet that many people remember all this.

Craziness of hi-fi fashion.... don't get me started on ''silver'' replacing ''black'' or the death of budget components...

hey, my view is I just dont like bi-amping (passively) or bi-wiring in any of the speakers or amplifiers Ive owned. Everthing sounded disjointed each time I tried it...

I guess its something everyone has to try to see if they like it..

 

While we are here... does anybody know if you can get Active crossovers built for one's particular loudspeakers? I remember seeing a small ad in Hifi World for someone who did this, but that was several years ago.

 

what I find interesting, to follow on from Bottleneck's neat history, is that some active loudspeakers I've read about have one amp per driver/cone. but I confess I'm far from expert, on theory or this history.

 

“The Crossover

Every component in the signal path can colour, distort or degrade the music. A minimalist crossover can eliminate these problems but will only function properly with drivers whose mechanical characteristics have been appropriately engineered. The ES22 uses purpose built drivers tailored specifically for this design. The resulting performance benefits are significant.

The midrange driver crosses over mechanically and is directly coupled to the power amplifier for maximum information retrieval and control. This makes the midband responsive, transparent and explicitly detailed. The bass driver and tweeter use single component networks solely to fine tune their integration with the midrange unit.â€Â

All good stuff and an excellent engineering solution.

If the midrange driver is directly coupled and the woofer and tweeter both use simple first order crossovers then you already have a distinct advantage.

Unfortunately, and despite the minimalist approach to crossover design, each amplifier in a pseudo tri-amped set-up will still be amplifying the full audio range. The frequency division needs to take place prior to amplification to reap the major benefits of bi-amping / tri-amping.

The misconception (I've seen) is that because one amplifier is powering the tweeter and another the woofer etc that each amplifier will only be amplifying those respective audio ranges – it doesn't work like this.

Pseudo tri-amping should sound better however – but no better than employing a more powerful amplifier in a conventional stereo configuration.

 

Audiolinks do them

 

I admire the strength of your assertion. So, in your view the bull aint tamed, and perhaps not even brought to knees.

What happens in active speakers? does the input from the pre-amp get disaggregated (or somesuch word) prior to amplification?

If you are right, then given that there are three sockets into the epos es22, I introduce some degredation in the construction of the 'bridge' that I use with one stereo amplifier.

 

Actives have active x-overs built in and amps. They filter the signal into relevant freq ranges and amplify them. It means the amps can be designed to fit the driver specs exactly (in theory). It also means the amp can drive the driver straight in as the crossing over has happened before the amp stages.

 

seems like a good question then...

 

ditton

Active loudspeakers receive a full-range line-level input or in other words are connected directly to a source component such as a CD player. In some instances this is done via a passive pre-amp to control volume levels if this feature isn't also part of the active loudspeaker.

The active loudspeaker houses a line level crossover (audio filters that operate at line level are infinitely preferable to loudspeaker crossovers – without going into detail you'll just have to trust me on this one!) this splits the full-range signal into low, mid and high frequency parts for a three-way loudspeaker design.

Each signal is then fed to separate power amplifiers which in turn are connected to respective low, mid and high frequency drivers.

 

Perhaps a gap in the market if no one is providing this service anymore!

Ideally the crossover used should be precisely matched to the specifications of the existing loudspeaker crossover and be passive. Active is only required where precise matching isn't possible (and too much adjustment away from the existing loudspeaker crossover values may cause problems).

Active crossovers are available from pro-audio suppliers from about £100.

 

i have certainly been thinking about having my ES30's converted to active. with the intention of using six monoblocks.

its finding appropriate crossover for such a system. and then getting enough information about the speakers and their drivers to be able to configure them appropriately.

active has many bonuses though... such as the ability to very easily slot in room equalisation upstream.. and the natural dynamics and sheer honesty of an active crossover can be invigorating. but at the same time it does make you very aware of problems downstream (not that ditton has that problem