I've decided to try and build a Meridian M2 active speaker clone. I have the cabinet dimensions and the schematic for the crossover but I need to source the drivers. It originally had KEF units, tweeter was either T52A (SP1049) or T52B (SP1072) and bass/mid was a pair of B110 (SP1057). Do I hang around on fleabay trying to find originals or are there modern alternatives (must be available in the UK) that would work?
Review | Meridian M2 active loudspeaker system | Page108 - August1981 - Gramophone Archive
Hi,
That really depends on the transfer functions built into the active x/o.
I'd start with downloading the TinaTi free emulator and modelling the schematic.
2" tweeters nowadays are not common, but some good ones exist
that can go low, Zaph|Audio ,
the SB acoustics SB Acoustics SB29RDC looks good.
There are other good tweeter choices, around the same or more.
There are now many small drivers with better motors than the B110.
Zaph|Audio . Dayton RS150S-8 looks good.
Zaph|Audio . Dayton RS128-8 looks good.
There are other good / bass mid choices, but somewhat more. There is no
real need to stick with exact box dimensions, a liitle bigger may work better.
The 6th order bass rolloff of the vented box needs to be redesigned using
the active filter part of WinISDPro or Basta!, and may need modifying
from the values in the Meridian active c/o.
It can be done, and done well with a fair amount of modelling, FRD tools.
I would not replicate the original in particular, the (used) drivers will be
expensive, more than new ones and not as good. The original bass
alignment was described as "thundery", I'd go tighter and deeper.
Internal amplifiers are an interesting choice, various way of
doing it and various ways of arranging the power supply.
Another option is an external power amplifier withv the bass function
and Any EQ buit into its feeback loop, and a simple passive x/o.
http://www.musicanddesign.com/HybridDesign.html
Its not a trivial project by a long chalk.
rgds, sreten.
Hi,
That really depends on the transfer functions built into the active x/o.
I'd start with downloading the TinaTi free emulator and modelling the schematic.
2" tweeters nowadays are not common, but some good ones exist
that can go low, Zaph|Audio ,
the SB acoustics SB Acoustics SB29RDC looks good.
There are other good tweeter choices, around the same or more.
There are now many small drivers with better motors than the B110.
Zaph|Audio . Dayton RS150S-8 looks good.
Zaph|Audio . Dayton RS128-8 looks good.
There are other good / bass mid choices, but somewhat more. There is no
real need to stick with exact box dimensions, a liitle bigger may work better.
The 6th order bass rolloff of the vented box needs to be redesigned using
the active filter part of WinISDPro or Basta!, and may need modifying
from the values in the Meridian active c/o.
It can be done, and done well with a fair amount of modelling, FRD tools.
I would not replicate the original in particular, the (used) drivers will be
expensive, more than new ones and not as good. The original bass
alignment was described as "thundery", I'd go tighter and deeper.
Internal amplifiers are an interesting choice, various way of
doing it and various ways of arranging the power supply.
Another option is an external power amplifier withv the bass function
and Any EQ buit into its feeback loop, and a simple passive x/o.
http://www.musicanddesign.com/HybridDesign.html
Its not a trivial project by a long chalk.
rgds, sreten.
Last edited:
If you can't get the original drivers, and I agree, you don't really want to, you are not building clones, but an improved design inspired by. The B110 was an amazing driver, for 1970.
With the Daytons, you do need to deal with the breakup modes. Actually, this is easier in an active system as you can use steeper filters, or go MiniDSP and do really nifty stuff. Don't get me wrong, very low distortion drivers for the price, but you need low steep crossovers for them.
As sreten mentions, going low is important. I am getting ready to try the SB instead of the Vifa's I have on a set of 150's as soon as I finish my metal vs fabric tweeter test. My 1.8K 2rd order electrical is not low enough. I am shooting for 1.6 4th. Teh SB is also a really good value driver. Doing better costs a lot more.
With the Daytons, you do need to deal with the breakup modes. Actually, this is easier in an active system as you can use steeper filters, or go MiniDSP and do really nifty stuff. Don't get me wrong, very low distortion drivers for the price, but you need low steep crossovers for them.
As sreten mentions, going low is important. I am getting ready to try the SB instead of the Vifa's I have on a set of 150's as soon as I finish my metal vs fabric tweeter test. My 1.8K 2rd order electrical is not low enough. I am shooting for 1.6 4th. Teh SB is also a really good value driver. Doing better costs a lot more.
Have a look at the Falcon Acoustics website (they're also on eBay). They have a lot of experience with designs based on the B110 and will be able to suggest more up-to-date drivers.
I'd use the cabinet shape and driver arrangement, otherwise model something from new. I'd also be inclined not to push the drivers too low and use a sub for the extra headroom you'd achieve.
I'd use the cabinet shape and driver arrangement, otherwise model something from new. I'd also be inclined not to push the drivers too low and use a sub for the extra headroom you'd achieve.
Thanks for the responses, you have pretty much confirmed my preferred choice of new rather than original drivers. Although the MiniDSP route would be interesting it would really be more like cloning the later Meridian DSP range of all digital speakers; and I'm not ready for that yet!
So I plan to stick with the same cabinet dimensions and same size drivers but the cabinet volume will be a little larger as I didn't plan to put the electronics inside the box. I'd like to reuse the crossover filter from the original hence my desire for drivers as close to the original spec as possible. Hopefully I can get away with the minimum in terms of tailoring the slopes for new drivers. There is a builtin 76 microsecond delay for time alignment in the crossover - would that be specific to the drivers or would it need changing also?
So I plan to stick with the same cabinet dimensions and same size drivers but the cabinet volume will be a little larger as I didn't plan to put the electronics inside the box. I'd like to reuse the crossover filter from the original hence my desire for drivers as close to the original spec as possible. Hopefully I can get away with the minimum in terms of tailoring the slopes for new drivers. There is a builtin 76 microsecond delay for time alignment in the crossover - would that be specific to the drivers or would it need changing also?
Hi,
You can't use the original electronics with other drivers, the built
in delay function is the least of you worries, you need to get a
grip on what you are trying to achieve. Having the original
schematic values is next to useless with different drivers.
You can copy the topology, with redesigned values.
rgds, sreten.
You can't use the original electronics with other drivers, the built
in delay function is the least of you worries, you need to get a
grip on what you are trying to achieve. Having the original
schematic values is next to useless with different drivers.
You can copy the topology, with redesigned values.
rgds, sreten.
Last edited:
Looking around I see that the accepted modern replacement for a B110 is the Monacor SPH-135/AD. The figures seem to match up pretty close and it should work pretty well with the cabinet dimensions. There's no obvious match for the T52 but the Morel CAT 308 looks like a popular replacement for the KEF T27 and isn't so far off the T52. They are modern "equivalents" in spec and hopefully in quality.
I think they would be more in keeping with the spirit of the project, otherwise I would have to take a punt on something less well known. In either case I know I will have to play around with the crossover to get this to work but being an active design means that, once I have built my power supply and bought a handful of op-amps, changing the parameters is relatively inexpensive compared to a passive crossover.
The only problem I see is that the above drivers are going to be a big chunk of change for me - about £275 ($425 US) so I need to be sure I can make something work out of this approach. Otherwise I will take recommendations for different drivers that would be more fail safe and give other exit options.
I think they would be more in keeping with the spirit of the project, otherwise I would have to take a punt on something less well known. In either case I know I will have to play around with the crossover to get this to work but being an active design means that, once I have built my power supply and bought a handful of op-amps, changing the parameters is relatively inexpensive compared to a passive crossover.
The only problem I see is that the above drivers are going to be a big chunk of change for me - about £275 ($425 US) so I need to be sure I can make something work out of this approach. Otherwise I will take recommendations for different drivers that would be more fail safe and give other exit options.
I would head over to Zaph and take a look at other tweeter reviews. A mid-line Seas or Vifa or even the SB for example are a lot less than the Morel and in my experience, superior. If I remember, the T27 took a lot to tame, but was worth the effort. You can spend a lot more in the crossover trying to "fix" it than a better tweeter costs. Bi-amped, it may not be as difficult. DSP, you get the "taming" for free.
Hi,
There is no such thing as direct equivalent replacement drivers.
The Monacor is one driver used for B110 clones, but the midrange is
different to the B110, you need to simulate the active c/o to see if any
midrange correction is applied and then change it for the Monacor.
SPH-135/AD - Monacor hiFi bass-midrange speaker 60Wmax 8Ω - Europe Audio
Not too bad at £35 each, but 2mm Xmax is a bit limp nowadays,
its actually worse than the B110 contrary to many claims that
it can produce more bass, basically it doesn't.
Without knowing what the active x/o actually does, your stumbling
around the dark, you need to model in a circuit simulator, period.
The 6th order bass alignment is boom box controlled by the active
x/o to something more manageable, you need to know its function.
The T27 and T52 are completely different tweeters.
The Morel CAT-308 :
CAT308 - Morel 1 inch coated silk softdome tweeter - Europe Audio
Is OK but not that cheap. Same price as this world class tweeter :
810921 - Peerless 1″ tweeter - Europe Audio
Loads more info and tests available.
Cheaper than both the above and very good on a tight budget is :
H1189-06 - Seas 27TDFC 1 inch tweeter - Europe Audio
Probably worth truncating its flange for tighter driver spacing.
Or overlapping flush bass mids/recessed tweeters like Dynaudio,
see : http://www.zaphaudio.com/mtg-surface.html
In todays world of HT speakers and most small drivers being
designed for use with a sub you have your work cut out to
make a decent fist of a 20L fully active full range speaker.
Me ? I'd consider 2x
SB15NRXC30-8 - SB acoustics 5 inch midwoofer - Europe Audio
and the Seas tweeter as a starting point, and model and
work from there, it you want something really good.
5mm xmax is a lot more like what is needed.
See Zaphs site for tests of both drivers.
rgds, sreten.
There is no such thing as direct equivalent replacement drivers.
The Monacor is one driver used for B110 clones, but the midrange is
different to the B110, you need to simulate the active c/o to see if any
midrange correction is applied and then change it for the Monacor.
SPH-135/AD - Monacor hiFi bass-midrange speaker 60Wmax 8Ω - Europe Audio
Not too bad at £35 each, but 2mm Xmax is a bit limp nowadays,
its actually worse than the B110 contrary to many claims that
it can produce more bass, basically it doesn't.
Without knowing what the active x/o actually does, your stumbling
around the dark, you need to model in a circuit simulator, period.
The 6th order bass alignment is boom box controlled by the active
x/o to something more manageable, you need to know its function.
The T27 and T52 are completely different tweeters.
The Morel CAT-308 :
CAT308 - Morel 1 inch coated silk softdome tweeter - Europe Audio
Is OK but not that cheap. Same price as this world class tweeter :
810921 - Peerless 1″ tweeter - Europe Audio
Loads more info and tests available.
Cheaper than both the above and very good on a tight budget is :
H1189-06 - Seas 27TDFC 1 inch tweeter - Europe Audio
Probably worth truncating its flange for tighter driver spacing.
Or overlapping flush bass mids/recessed tweeters like Dynaudio,
see : http://www.zaphaudio.com/mtg-surface.html
In todays world of HT speakers and most small drivers being
designed for use with a sub you have your work cut out to
make a decent fist of a 20L fully active full range speaker.
Me ? I'd consider 2x
SB15NRXC30-8 - SB acoustics 5 inch midwoofer - Europe Audio
and the Seas tweeter as a starting point, and model and
work from there, it you want something really good.
5mm xmax is a lot more like what is needed.
See Zaphs site for tests of both drivers.
rgds, sreten.
Last edited:
In many ways it would make it easier than doing it analogue. I've done both many times and don't see a lot of up side to doing it analogue these days.
I take your point sreten and will officially ditch the old driver approach. The specs for the two modern drivers you mention look decent enough and you've saved me some money on the tweeters. Not sure about the Dynaudio driver arrangement but it sounds quite a lot like my Sonus Fabers <http://s140.photobucket.com/albums/r3/ykbucket/?action=view¤t=SonusFaberElecta.jpg&newest=1>.
So what next? I'll admit now that I'm new at this game, but a look at the squiggly lines on the graphs for the two drivers makes me think about a crossover at around 2K. I'll worry later about doing it with a MiniDSP or a handful of op-amps.
So what next? I'll admit now that I'm new at this game, but a look at the squiggly lines on the graphs for the two drivers makes me think about a crossover at around 2K. I'll worry later about doing it with a MiniDSP or a handful of op-amps.
You've missed the point of the Meridian speaker you are trying to clone. 
Dome midranges have some very interesting time-aligned properties. With a crossover around 700Hz, they naturally time align themselves with the woofer even on a flat baffle. This is because wavelength is a foot or so at that frequency. It's astonishing how well they work, and you can add a regular tweeter above 5kHz on a second order too.
Try modelling some of Visaton's models in Boxsim. Visaton don't make any plastic cones, but you'll get close with the shallow W130S bass/midrange and G 50 FFL dome midrange on second order filters.
Visaton - Lautsprecher und Zubehör, Loudspeakers and Accessories
Dome midranges have some very interesting time-aligned properties. With a crossover around 700Hz, they naturally time align themselves with the woofer even on a flat baffle. This is because wavelength is a foot or so at that frequency. It's astonishing how well they work, and you can add a regular tweeter above 5kHz on a second order too.
Try modelling some of Visaton's models in Boxsim. Visaton don't make any plastic cones, but you'll get close with the shallow W130S bass/midrange and G 50 FFL dome midrange on second order filters.
Visaton - Lautsprecher und Zubehör, Loudspeakers and Accessories
What dome midrange are you referring to? The T52 in the Meridian is used as a conventional tweeter with a crossover at 1.75KHz.
Meridian M2 Specification
Meridian M2 Specification
I contacted Falcon Acoustics regarding replacement drivers and they have suggested that the dual voice coil version of the Monacor, the SPH-135/TC, would actually be a better bet and save me some money as well. But it still only has a cone excursion of +/-2.25mm which isn't much better than the SPH-135/AD.
Hi,
You can build a modern update of the M2 properly or mess about
with something that is vaguely like the M2, its hard to tell what
is planned here regarding regarding box quality and electronics.
A lot of the active electronic functions can be built into the
feedback loops of the power amplifiers if you know what
you are doing.
Do you want a stand mounted M2 lookalike ? Does it need
to work without a subwoofer or with one ? That makes a
big difference in what your attempting to do and why.
To build an active fully integrated speaker you can't take a
piecemeal approach IMO, there is lot to consider overall.
rgds, sreten.
http://sites.google.com/site/undefinition/diy (see if nothing else, the excellent FAQs)
The Speaker Building Bible - Techtalk Speaker Building, Audio, Video, and Electronics Customer Discussion Forum From Parts-Express.com
Zaph|Audio
Zaph|Audio - ZA5 Speaker Designs with ZA14W08 woofer and Vifa DQ25SC16-04 tweeter
http://audio.claub.net/Simple Loudspeaker Design ver2.pdf
FRD Consortium tools guide
Designing Crossovers with Software Only
RJB Audio Projects
Jay's DIY Loudspeaker Projects
Speaker Design Works
HTGuide Forum - A Guide to HTguide.com Completed Speaker Designs.
A Speaker project
DIY Loudspeaker Projects Troels Gravesen
Humble Homemade Hifi
Quarter Wavelength Loudspeaker Design
The Frugal-Horns Site -- High Performance, Low Cost DIY Horn Designs
Linkwitz Lab - Loudspeaker Design
Music and Design
Great free SPICE Emulator : SPICE-Based Analog Simulation Program - TINA-TI - TI Tool Folder
You can build a modern update of the M2 properly or mess about
with something that is vaguely like the M2, its hard to tell what
is planned here regarding regarding box quality and electronics.
A lot of the active electronic functions can be built into the
feedback loops of the power amplifiers if you know what
you are doing.
Do you want a stand mounted M2 lookalike ? Does it need
to work without a subwoofer or with one ? That makes a
big difference in what your attempting to do and why.
To build an active fully integrated speaker you can't take a
piecemeal approach IMO, there is lot to consider overall.
rgds, sreten.
http://sites.google.com/site/undefinition/diy (see if nothing else, the excellent FAQs)
The Speaker Building Bible - Techtalk Speaker Building, Audio, Video, and Electronics Customer Discussion Forum From Parts-Express.com
Zaph|Audio
Zaph|Audio - ZA5 Speaker Designs with ZA14W08 woofer and Vifa DQ25SC16-04 tweeter
http://audio.claub.net/Simple Loudspeaker Design ver2.pdf
FRD Consortium tools guide
Designing Crossovers with Software Only
RJB Audio Projects
Jay's DIY Loudspeaker Projects
Speaker Design Works
HTGuide Forum - A Guide to HTguide.com Completed Speaker Designs.
A Speaker project
DIY Loudspeaker Projects Troels Gravesen
Humble Homemade Hifi
Quarter Wavelength Loudspeaker Design
The Frugal-Horns Site -- High Performance, Low Cost DIY Horn Designs
Linkwitz Lab - Loudspeaker Design
Music and Design
Great free SPICE Emulator : SPICE-Based Analog Simulation Program - TINA-TI - TI Tool Folder
Good points, which I will try to address. Perhaps I was a little fanciful in imagining that I could find what I was looking for using off the shelf parts with a bit of DIY thrown in. To be honest, this is more for my own intellectual stimulation rather than the goal of audio nirvana (I already have another system for that). So I actually find this discussion very useful as it shows me I have a more challenging task ahead of me.
As for the amps, I hadn't considered them as part of my project - even though I know there were an obviously integral part of the original M2. They were just variants of standard Meridian amps partnered with an active crossover. I don't see much reason to deviate from that especially since I already have a pair of amps to work with. Maybe in the future I might consider a more closely coupled approach and build a set of chip amps to power it all.
I think the choice of subwoofer or not is pretty crucial - as you pointed out earlier, few modern 5 inch drivers are now considered real bass units. I'll be honest and say that I don't much like subwoofers. I've no particular desire to think about incorporating one now and would be unlikely to want to revisit the design and add one afterwards. So I'm looking to make the best I can of the MTM driver layout with a front port, HxWxD of 500x180x375 and an active crossover. I don't have an unlimited budget but the drivers discussed so far would be the right sort of price point.
Hi,
Well the Seas tweeter can be massaged into L/R 4th order acoustic
at around 1.5KHz with a 2nd order active high pass filter AFAICT.
Phase delay at the x/o point can be dealt with a all pass delay network
or some asymmetry in the target 4th order L/R acoustic response.
Given MTM's are vertically symmetrical the assymetric is simplest IMO.
The bass/ mid drivers will need baffle step correction and without a sub
an active 6th order bass alignment. Quick modelling of the suggested
SB bass mids suggests a box tuning of around 33Hz would work.
The active part doesn't need to be complicated, 3 op-amps per channel.
Amplifiers can be pretty much the same, with the same supply, but double
devices for the bass/mids for double 4ohm levels re the treble amplifier.
Different separate amplifiers around 3 or 4 times the power into 4 ohms
for the bass/mids than the treble amplifier into 8 ohms is about right.
It is doable. 2x5"/1" MTM x/o around 1.5KHz in a 20L box tuned to
33Hz. Driver layout suggested is like your Sonus Fabers, overlapping.
But to build it, you need to work out all the details from the links provided.
rgds, sreten.
Well the Seas tweeter can be massaged into L/R 4th order acoustic
at around 1.5KHz with a 2nd order active high pass filter AFAICT.
Phase delay at the x/o point can be dealt with a all pass delay network
or some asymmetry in the target 4th order L/R acoustic response.
Given MTM's are vertically symmetrical the assymetric is simplest IMO.
The bass/ mid drivers will need baffle step correction and without a sub
an active 6th order bass alignment. Quick modelling of the suggested
SB bass mids suggests a box tuning of around 33Hz would work.
The active part doesn't need to be complicated, 3 op-amps per channel.
Amplifiers can be pretty much the same, with the same supply, but double
devices for the bass/mids for double 4ohm levels re the treble amplifier.
Different separate amplifiers around 3 or 4 times the power into 4 ohms
for the bass/mids than the treble amplifier into 8 ohms is about right.
It is doable. 2x5"/1" MTM x/o around 1.5KHz in a 20L box tuned to
33Hz. Driver layout suggested is like your Sonus Fabers, overlapping.
But to build it, you need to work out all the details from the links provided.
rgds, sreten.
Last edited:
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