[AngelEyes]

Hi,

I have never Bi-Amped before and am curious how it is done and the relative benefits.

My amp has six channels that I currently run bridged for the front three speakers.

What advantages would I expect if I Bi-Amped instead? Am I also correct in thinking there exists passive and active Bi-Amping or did I just invent that?

Can someone explain the pros and cons?

Much obliged

Adam

[Gixxerblade]

Have a look at Rod Elliot's articles including this one BiAmp (Bi-Amplification - Not Quite Magic, But Close) - Part 1
Some people have had excellent results (or say they have) bi-amping passive crossovers so as usual the only way is to try for yourself.

[lbstyling]

its well worth investigating, and i have had exellent results.

its a obvious improvement when i run stereo, particularly obvious when i have my seas excel speakers running as there a heavy load and more importantly in this case- they are a high inductance design (same as all metal cane drivers, and a charateristic of heavy/long throw drivers in general)

the more your speakers have to physicaly move forward and back, the bigger the difference is between a single channel speaker and a bi/tri-amped one, this is because (without getting too tecnical) drivers create back emf when they move, this generates a signal. when you connect drivers together in a crossover circuit - the signal that is generated by say the bass driver is independant of the signal going into it - it plays its own 'tune' through the other drivers at a low level by affecting the original signal.
the more information going into the speaker (volume of or amount of) the more effect the drivers have on each other- the bass driver is particularly responsible for this.

if it helps- look at it this way- a speaker is a mic, they are the same thing, just smaller or larger. so it can put info in or out- we just only use it as a output!


-im pushed to justify doing it with my reciever as the quality is bottlenecked at the reciever in my case- having said that, i can still tell a reasonable difference- its just i wouldnt pay out £3000 for this amount of improvement in this case.


there many technical reasons why its an improvement and there not all what you would expect- the site suggested above is an excelent place to start.

if it helps- the ultimate system would be fully active (ie the crossover would be between the pre amp and you would have one power amp per driver)theres no doubt this is vastly superior to a normal system- however in practice its not going to be so good- ive tryed it 2 ways myself-

1- a digital active crossover that is calibrated and crossed over using real measurements and predicted information from a computer program - the only unit that will do this for anything like the kind of money normal people have happens to be one of the cheapest and best units- its the behringer dcx 2496- this has got to be one of the most searious pieces of kit you'll ever encounter -and only costs about £250!!!
you just wont beleave what this thing can do- it can take a digital signal from your transport and split it into 8 channels of information (4 left and 4 right) then it rolls off the top and bottom of each channel where you set it to-
i could write a book on the advantages of this to tweeter difraction and time/phase allignment, but im bridging into speaker designing stuff.
the problem with this method is one i know youll understand given resent threads here angel, jitter. massive amounts of jitter. along with a large scoop of poor dac's and poor analogue stages.- its not even remotely audiophile.- there lots of information on improving it and even companys who specialise in this (look up audiosmile) -but imo you cant polish a turd this bad.

2- a analogue line level crossover- despite the fact that its very basic compaired to the digital solution- it will sound superior to it if you use a fairly good one (i recommend dbx)- it will only crossover at a set order (usualy 4th-24db/oct) and avoids many problems that require some serious work to get around in a passive speaker crossover-and i mean SEARIOUS WORK- it took me 2 years to design and build my speakers.
the problem with this is its not a good solution for most speakers as you cant do anything other than cross over- no zorbel networks or baffle step att or notch filtering ect- nothing. and these thing are usualy needed for high fidelity audio.

so although i have no doubt at all that audio nervana is this way- were not there -not yet.

you can get many of the advantages of this tech by bi-amping, and so in practice its superior at the moment to going active.
if you combined it with a pllxo, your looking towards reference level playback technology.

what does it sound like??

well - i find it separates instruments better, the decay of complicated music like coldplay seam to benefit the most, becoming somthing you can follow better through the swamp of instruments that all have echo effects of there own each overlapping each other.
i have found that the differences between class a and a low bias a/b amp become more noticable in my system when bi-amping. and that the differences between all in one power amps like mine and monoblocks also have a stronger effect- your into a painfull wallet zone when you start to here this.

there is -ALOT more to it than this, even the ESP pages only touch on some of it- but im not writing a book here.

hope that helps!

ps- cons- expensive, and more boxes....thats it!

[AngelEyes]

Thanks for the input chaps.

Having read and understood (some) of that article it seems the main benefits of bi-amping would be an active route, bypassing the passive crossovers? This is realistically not something I am going to attempt just yet.

If I was to proceed with passive bi-amping the benefits seem to be to seperate the bass from the mid/tweeter. The thing is I roll my mains off at 80hz so the bass drivers in the L&R aren't doing all that much work, so it makes me wonder if I would be getting as much benefit as someone not using a sub?

With my present Receiver, I assume I would have to buy y-splitters for the pre-outs to achieve passive bi-amping?

What of Processors such as the 5507 that support Biamping? Is this a better method of Bi-Amping or just a convenience thing?

Sorry for all the questions.

Adam

[crobo]

Bi-amping works well with my speakers and I'm not sure whether it is due to the increased power on offer, or the separation between drivers (or both). I suspect each speaker type will react differently.

If the power amp doesn't have pre-outs (like the P7 does for example) you need Y-splitters. Mark Grant does sets for £40-odd.

[Mark.Yudkin]

Ibstyling and Medrep1 have addressed the question of what biamping does, but both seem to have skipped the fact that you're already bridging, and wonder about the relative benefits of bridging vs biamping.

Biamping is about getting the consequences of the low frequencies, which typically need more power, away from the finer control needed for the mids/highs, where the ear is more sensitive to (harmonic) distortion. Since distortion rises with power draw, the consequence of lower power draw for the mids/highs is a lower distortion. Distortion at low frequencies goes pretty much unnoticed (just look at the huge distortion figures of even expensive subwoofers). Biamping doesn't have any effect on the quality of the bass - nor would any be expected.

Biamping is not about power per se: you do not get any higher power by partitioning by frequency. Bridging by contrast is about ca. doubling the power. If you need the extra power, stick with bridging. If you don't need the power but have too much distortion, use biamping. Needless to say, one higher quality amp will outperform two lower quality amps, so both bridging and biamping are techniques to use when you've already reached the top.

[rags]

Simple biamping does bring about some benefits. My Kef Reference speakers sound a touch cleaner and punchier biamped with an Arcam P7 than they did without.

However I man not that impressed with the P7 - its weedy imho and I honestly believe my Parasound A52 in single mode is meatier. I have no experience of the Cinepro but its sounds like a bit of a beast especially if you are bridging the channels for your front speakers. You are probably giving them more power than they will ever need + given your rolloff is set to 80hz you are unlikely to be putting any kind load on the amp. You can try simple biamping but I am not sure in your case that it will improve anything. Willing to take a punt that even bridging the amp for your fronts doesn’t change the sound significantly versus driving them with single channels (maybe a touch louder)?

Maybe a speaker upgrade required - more in keeping with your amp ?

[AngelEyes]

Originally Posted by rags

Simple biamping does brong about some benefits. My Kef Reference speakers sound a touch cleaner and punchier biamped with an Arcam P7 than they did without.

However I man not that impressed with the P7 - its weedy imho and I honestly believe my Parasound A52 in single mode is meatier. I have no experience of the Cinepro but its sound like a bit of a beast especially if you are bridging the channels for your front speakers. You are probably giving them more power than they will ever need + given your rolloff is set to 80hz you are unlikely to be putting any kind load on the amp. You can try simple biamping but I am not sure in your case that it will improve anything. Willing to take a punt that even bridging the amp for your fronts doesn’t change the sound significantly versus driving them with single channels (maybe a touch louder)?

Maybe a speaker upgrade required - more in keeping with your amp ?

I am still loving the speakers so not feeling any need to upgrade at the moment, the Receiver is the obvious weak link at the moment.

I have to agree with your findings on the P7 despite much praise it gets here, the only thing it gives more of than anytghing else is heat. The Cinepro is a different story but in bridged it admittedly doesn't add a great deal more, however I still like the thought of all that power .

Thanks for all the replies.

Adam

[lbstyling]

Originally Posted by Mark.Yudkin

Ibstyling and Medrep1 have addressed the question of what biamping does, but both seem to have skipped the fact that you're already bridging, and wonder about the relative benefits of bridging vs biamping.

Biamping is about getting the consequences of the low frequencies, which typically need more power, away from the finer control needed for the mids/highs, where the ear is more sensitive to (harmonic) distortion. Since distortion rises with power draw, the consequence of lower power draw for the mids/highs is a lower distortion. Distortion at low frequencies goes pretty much unnoticed (just look at the huge distortion figures of even expensive subwoofers). Biamping doesn't have any effect on the quality of the bass - nor would any be expected.

Biamping is not about power per se: you do not get any higher power by partitioning by frequency. Bridging by contrast is about ca. doubling the power. If you need the extra power, stick with bridging. If you don't need the power but have too much distortion, use biamping. Needless to say, one higher quality amp will outperform two lower quality amps, so both bridging and biamping are techniques to use when you've already reached the top.

the first part of this is good stuff -but your generalising a little about bi-amping vs bridging, as i mentioned earlyer - there is more to this than just the mentioned aspects in even the ESP pages.(which are exelent by the way)

another main aspect of improvement over bridging is damping factor- to control the bass of a speaker from time smear distortions( for one thing), a aspect of amp design is damping factor, its a restoring force to the cone movement after a signal is delivered that pulls the diaphram back in to static position.
the more complicated a crossover-(this usualy means higher order) the more components between the driver and one of its main restoring forces. these use up the restoring force, and so in turn reduce its effectiveness.
this is again more of a issue with heavy diaphrams- like angels xtz's- some of the heavyest.

again- the theory of active is superior, but the reality is inferior at the moment. for now -unless you got mega money to burn, bi-amping is the best you can get.

although every situation is different, all things being equal, theres a stronger case for 2 sonically inferior amplifiers being superior to a single better one, than the other way around.
distortion levels of 2 inferior amps running as biamps are more than likely to have lower distortion levels at the same spl in every measureable way - IM, crosstalk, thd,...-the only aspect that may or may not be as good is SNR. -it will improve over using a cheaper amp as a standard stereo setup, as theres only 1 signal going into the amp,but a better amplifier may well have a better internal layout/implimentation.
in the other areas, the measurable levels of various distortion vary surprisingly little between the vast majority of modern amplifiers-whereas bi-amping reduces all these considerably- in many cases beyond the levels possible within a normal power amplifier connected to speakers(IM distortion for example)

add to all this that your tweeter will likely not use enough power to move into class b operation(depending on the bias of corse)-you have also effectively changed half your amplification to class a- and right where your sensitive to improvements too!!
this will not happen by bridging.

that all adds up to quite some difference- again especially if your speakers are a heavy load.

and theres still many more aspects of benifit than this!!!!!!!!!!!

[lbstyling]

Originally Posted by Mark.Yudkin

Ibstyling and Medrep1 have addressed the question of what biamping does, but both seem to have skipped the fact that you're already bridging, and wonder about the relative benefits of bridging vs biamping.

Biamping is about getting the consequences of the low frequencies, which typically need more power, away from the finer control needed for the mids/highs, where the ear is more sensitive to (harmonic) distortion. Since distortion rises with power draw, the consequence of lower power draw for the mids/highs is a lower distortion. Distortion at low frequencies goes pretty much unnoticed (just look at the huge distortion figures of even expensive subwoofers). Biamping doesn't have any effect on the quality of the bass - nor would any be expected.

Biamping is not about power per se: you do not get any higher power by partitioning by frequency. Bridging by contrast is about ca. doubling the power. If you need the extra power, stick with bridging. If you don't need the power but have too much distortion, use biamping. Needless to say, one higher quality amp will outperform two lower quality amps, so both bridging and biamping are techniques to use when you've already reached the top.

the first part of this is good stuff -but your generalising a little about bi-amping vs bridging, as i mentioned earlyer - there is more to this than just the mentioned aspects in even the ESP pages.(which are exelent by the way)

another main aspect of improvement over bridging is damping factor- to control the bass of a speaker from time smear distortions( for one thing), a aspect of amp design is damping factor, its a restoring force to the cone movement after a signal is delivered that pulls the diaphram back in to static position.
the more complicated a crossover-(this usualy means higher order) the more components between the driver and one of its main restoring forces. these use up the restoring force, and so in turn reduce its effectiveness.
this is again more of a issue with heavy diaphrams- like angels xtz's- some of the heavyest.

again- the theory of active is superior, but the reality is inferior at the moment. for now -unless you got mega money to burn, bi-amping is the best you can get.

although every situation is different, all things being equal, theres a stronger case for 2 sonically inferior amplifiers being superior to a single better one, than the other way around.
distortion levels of 2 inferior amps running as biamps are more than likely to have lower distortion levels at the same spl in every measureable way but . IM, crosstalk, thd,...-the only aspect that may or may not be as good is SNR. -it will improve over using a cheaper amp as a standard stereo setup, as theres only 1 signal going into the amp, a better amplifier may well have a better internal layout/implimentation.
in the other areas, the measurable levels of various distortion vary surprisingly little between the vast majority of modern amplifiers-whereas bi-amping reduces all these considerably- in many cases beyond the levels possible within a normal power amplifier connected to speakers(IM distortion for example)

[AngelEyes]

The next time I have some money burning a hole in my pocket I will get some more cables and try it out. With 15m runs to the fronts it may be a little while though

Thanks,

Adam

[rags]

Originally Posted by AngelEyes

I am still loving the speakers so not feeling any need to upgrade at the moment, the Receiver is the obvious weak link at the moment.

I have to agree with your findings on the P7 despite much praise it gets here, the only thing it gives more of than anytghing else is heat. The Cinepro is a different story but in bridged it admittedly doesn't add a great deal more, however I still like the thought of all that power .

Thanks for all the replies.

Adam

Think about your electricity man. Straight swap for my A52 ? Your speakers deserve to be beaten up a little less than they currently are

[Mark.Yudkin]

I agree that I simplified. I skipped active vs passive crossovers as you had already covered it in detail and the OP had indicated that an active crossover was not "something he was going to attempt just yet". (Active speakers were also probably not relevant, so I didn't open that can of worms).

[strongdeo]

Hello! I want to try bridging but can I do that with the MP150s or the S150s?

THanks

Dave

[lbstyling]

Originally Posted by Mark.Yudkin

I agree that I simplified. I skipped active vs passive crossovers as you had already covered it in detail and the OP had indicated that an active crossover was not "something he was going to attempt just yet". (Active speakers were also probably not relevant, so I didn't open that can of worms).

fair enough.

i have a little 'extra' insight into the subject in this particular case, as angel uses a common diy design in his speakers-(if i remember correctly-seas excel w18 and a neo 3.0 tweeter)
this bass driver is at xmax (maximum linear travel with the coil having all windings within the full magnetic field) with 20w peak input-before the port tuning will roll off.-theres many losses to going past this point- for one-dynamics will suffer. another aspect is that any extra power isnt applied to the whole coil so its gains drop off fast- this is why people often report better control with 1000wrms amplifiers- if only they knew that having a larger speaker that managed the target spl within the range of xmax would be better in nearly every way on 40w!

of corse theres other factors to consider (swmbo ect)- because when designing the speaker, it will start getting bigger mightly fast when your trying to improve distortion figures!- hence the size and shape of the 'modern' speaker.

so a 70's style speaker with modern drivers is a formidable thing!

in your case- if you find a benefit in using significantly more power than 20w- your speakers are playing at a level over there optimum useable low distortion range- so bridging in this case would be somewhat treating a symptom.

i realy recommend those that want to push the boundries of the subject to look into diy- starting with vance dickasons 'loudspeaker design cookbook'. -a eye opener to say the least.

[Mark.Yudkin]

In your case - if you find a benefit in using significantly more power than 20w- your speakers are playing at a level over there optimum useable low distortion range- so bridging in this case would be somewhat treating a symptom.

My specific case (see sig) is anyway rather different: a voltage driven push-pull capacitative load with low impedance at high frequencies and high impedance at low frequencies, no crossover and a low mass, full range membrane. With current draw being inversely proportional to impedance, the low efficiency speakers (86db/2.83V/1m, permitted: 10V continuous, 40V peak) consume power without being all that loud. But this is not Adam's situation, or yours.

On the subject of whether "2 sonically inferior amplifiers are superior to a single better one", or not, we'll need to agree to disagree. Since he can, Adam should try out both options and make up his own mind.

[AngelEyes]

So would the consensus be I have way too much power on my speakers? I always assumed more = better.

Thanks.

Adam

[lbstyling]

you cant have 'too much'- it wont do any harm having the reserve current. -besides if your going to drive the speaker past xmax -you will need plenty of it.
the ideal solution (swmbo aside) is a speaker that passes your spl playback level with ease and then some.-however there is a strange phenomina that users tend to play there systems naturaly at a level where the distortion doesnt rise above a certain level-when they are given a setup that distorts by the same amount at double the first speakers volume- that tends to be there perfered playback level.

you need to understand whats physically going on in your speakers once you cross xmax- and i dont have any diagrams to show you!!
the further you drive the cone past the point where the magnet has grip over the whole coil, distortions rise massively.
in your case this is around 100-102db (xmax +15% @1m)for the base unit (without being crossed over to the sub)
dynamic content and distortion will suffer considerably past this spl-but only on the peaks.
so this kills the energy of the performance for one thing.

the problem is you cant just pull out a spl meter and see if you listening at this level, because its already compressing transients. (dbA weighted by the way)
but if you are aproaching it then yes realisticaly this problem will be affecting you. i wouldnt be put out though- from what i see i would say that 98% of people here on the forum are pushing there drivers past xmax.

now, you can physicaly push a driver often a long way past xmax, particularly if the driver is a true 'long throw' design ( ie it has a long coil-as opposed to just a large excursion) this is used in many a sub.
some drivers will move more than double there xmax!- but this isnt hifi, because its a bouncy castle not a speaker and its not in the slightest bit acurate.

all things being correct and equal, you need double the power to increase spl by 3db (db is logarhythmic)-however this isnt true past xmax. because the further you go past it, the less area of coil you have to control with your increasing magnetic force.( partialy the reason for lost dynamics) untill ultimately you blow the driver-either by thermal limitation (the coil cooks partially because it cant cool by moving further) or physical (in your case it hits the end plate)

but again, by even approaching these aspects theres prices to pay- when the coil temp rises its changes the resistance of the driver- meaning the crossovers are incorrect for one thing because you just added a resistor.
IM distortion rises massively with increasing movement of the coil anyway so driving any speaker diaphram more than a couple of mm is a loosing battle from the start- beleve me when i say that amplifier quality and distortion is very much second to speakers.
the lowest distortion speakers in the world are 10's if not 100's of times more distorted than a £10 maplin diy play-amp.

in summary,
crossing xmax isnt the end of all things -but its a loosing battle, if you find that you audiably need much more than 80w in your case, i would suggest that you look to the speakers for a different aproach to the problem

- this is where some people unknowingly head towards high efficiency/valves, you can get some amazing sounds out of valves- but only with high eff speakers, -the high eff speakers have (unknowingly to the purchaser)high max spl capablilties- so sound wonderfull, but the user thinks its the valves that have given them this- that may be the case for sme part of it -but i assure you its mostly the speakers.

[IWC Dopplel]

This is old but useful and interesting

http://www.hificritic.com/downloads/collomsbiwiring.pdf

[stevefish69]

Sorry for Hi-jacking your thread Adam

Interesting reading there guys. I'm kind of getting where you are coming from with regards to the position of the exposed voice coil covering the complete magnet but....

How come my speakers have showed such vast improvements with each increase in power (wattage and amps) available to them. Surely if my old power amp drove them properly to the sweet spot (volume) then the extra they now have should have made no difference

Distortion has appeared to decrease whilst playing back at the same SPL and well above. They max out at 115db and are failrly sensitve at 92db/watt IIRC

[lbstyling]

Originally Posted by stevefish69

Sorry for Hi-jacking your thread Adam

Interesting reading there guys. I'm kind of getting where you are coming from with regards to the position of the exposed voice coil covering the complete magnet but....

How come my speakers have showed such vast improvements with each increase in power (wattage and amps) available to them. Surely if my old power amp drove them properly to the sweet spot (volume) then the extra they now have should have made no difference

Distortion has appeared to decrease whilst playing back at the same SPL and well above. They max out at 115db and are failrly sensitve at 92db/watt IIRC

as mentioned before, there is scope for improving the sound by increasing the avaiable power.

from a design point of view-

one of the methods of increasing available power (the main method-because its free) in a amplifier is increasing the feedback- this also increases the control over the cone movement (damping factor)
so- generalising a bit, -a amp designed to have lots of power as its main criteria will have high feedback.(especially if its cheap)
feedback local or global is a timing error.-like jitter.

what im saying is its not the answer.

for another example-
if you playback at 100db average level- the peaks will likely be over 110db and potentialy up to 120db,
now if your speakers are 92db/1w, (forgive me -but that likely means 90db/1w at full operating temp-i have found most manufacturers state this level when cold)they would take 8w to get to 101db.-to get to 110db you would need 64w.
now i dont know your speaker intimately -but, if its got 1 or 2 -6inch cones for the bass driver and is your standard affair (sise/shape) arround 25l cabinet ect, i would guestimate its xmax at around 7mm for the bass driver(s).
they will cross xmax long before they reach 115db.
for example, a recent commercial speaker i tested of this type (also stated as 92db/1w) leap indicated xmax at 100db- after this point any spl increase is substantialy and exponentialy less than the optimum 3db for doubling input power.

this taken into context- to reach the 115db or even 110db your speakers list as max output it could take hundreds of watts
add to this the fact that many amps dont double there output into a halving impedence- when your speaker drops a low note needing 200w/4ohms at 35hz - the amp may only give you 170w @ 4 ohms yet 100 @ 8- meaning you have lost output here too.

what im saying is the ideal world solution is a 100db/1w speaker.= 111db @16w. - a well designed 20w amplifier will drive this well -and could be reasonably quality for much less.- class A, 0 feedback, valve,low IM and noise floor (due to low operating current demands (smaller tranny ect)- you could easily afford a dual mono construction ...etc... etc.

if the cone area is large enough- you could do it all within xmax aswell!!

the fact is that if you are realy serious about your audio- you will have tryed the described speakers eventually.
- anything smaller IS a large compromise- all be it one than the majoritly sadly need to make.

go build one of these!.....DTQWT

[Gixxerblade]

Adam
If you haven't seen this already from the Arcam sub-forum it is worth reading, note the different opinions on page 2 onwards, there is also a thread about tri-amping with 2 x P777 which is also worth a read.
http://www.avforums.com/forums/arcam...ston-amps.html
P777 thread here:
http://www.avforums.com/forums/arcam...vote-p777.html

[Ianfromnotts]

I tried using my 5 channel amp to passively Bi amp the fronts was was very impressed by the improvements made. In the end I didnt go down that route as I needed the amp to power the rears and used a stereo amp on the front but have just bought a 6 channel amp to try passive Tri Amping. I will let you know how I get on. It will be interesting to see how 2 x 3 lower spec amps compare with 2 x 1 channel higher spec balanced amp from the same stable.

Let you know how I get on but might take a week before I can report

[stevefish69]

Originally Posted by lbstyling

now i dont know your speaker intimately -but, if its got 1 or 2 -6inch cones for the bass driver and is your standard affair (sise/shape) arround 25l cabinet ect, i would guestimate its xmax at around 7mm for the bass driver(s).

Thanks for the responce, i knid of get where you are coming from

My Kef's actually have two internal 8" Bass units, a 6.5mm LM, a 6.5mm HM and normal tweeter. IIRC the bass drivers each have their own 75l cabinet and vent via the front coupled cavity hole.

[lbstyling]

Originally Posted by stevefish69

Thanks for the responce, i knid of get where you are coming from

My Kef's actually have two internal 8" Bass units, a 6.5mm LM, a 6.5mm HM and normal tweeter. IIRC the bass drivers each have their own 75l cabinet and vent via the front coupled cavity hole.

so, ive been off work today and bored- i thought i would look into your speaker (as ive got the time!)

mmm- interesting!!
it seams a particularly well designed unit-assuming the stereophile measurements are good.
now-stereophile use a mlssa analizer- so im conviniently familiar with the test kit.
the fr response graph looks heavily smoothed- but this is to be expected- now the first thing of note is that your speakers have a f3 of arround 28hz (low port tune)-but a internal volume of 70l!!
now the reason for mentioning this is im going to try in some way predict the sound of the low end.
2x8inch drivers optimised for a 70l enclosure will have to have a high qtc as thats the trade off- qtc is the perameter that dictates the ability of the driver to return to rest after a signal- this measurement combined with the box sise gives you the qts- a low qts is a fast driver= tight.

your design is optimised for extention so the qts is high= warm, and can become percieved as boomy.- the speaker would perform better optimised to a cabinet prob arround 150l(it would also play lower!). the closer you can get the qts to 0.47 or so- the better.

the waterfall graph shows this- with the bass response remaining after the treble by a considerable margin.

im not knocking the design- it looks surprisingly good to me- im just saying that physics cant be avoided-even in this large speaker!
open baffle designs may have the ultimate edge here.- but again theres always compromises!

a speaker will only ever have the potential to be massively better if you take the constraints off.

[stevefish69]

OMG - You certainly know your stuff

Thanks a million for taking the time to respond. Most of that's just gone right over my head. I don't think the'd fit in my room if the Bass enclosure was 150l. Thanks again - I'm off to watch a film