DIY audiophile 2-way drivers for ~$350? Please help>

Hi all. New guy here who's had an interest in audio for a long time but never really taken the plunge.

I've built quite a few car audio enclosures before (sealed, vented, 4th order) and have a good Ryobi BT3100 tablesaw, jigsaw, etc and am quite capable of making about any type of enclosure, even quite complicated ones. I've also made up first order crossovers, but nothing spectacular.

What I want is to build are some really good speakers for listening to in a living room setting. Room is perhaps 12x20 (moving to a new house, not exactly sure of the dimensions off the top of my head). The drivers will perform everyday stereo TV sound duty also, and perhaps HT duty later on. I like most types of music except country. I suppose I lean more towards rock and electronic music if I had to pick genres. But, I want to be able to enjoy jazz/classical and other "detailed" music types also.

I was thinking of starting with a 2-way system with perhaps a 6"+ woofer (not set on that) and a tweeter. Don't have my heart set on any type of tweeter, so am open to suggestions. Was thinking I didn't want to go ported, as I was hoping for some "high end" speakers and want tight, accurate bass. Again, I could be persuaded differently though. I have a 12" sub and amp now, so the lower bass doesn't need to be of really high importance. However, I'm hoping to build something of much higher quality than my sub, so if I can get away without the sub and the resulting cleaner sound I will be happy. I figure $350 for the drivers (4) is about right?

OK, as to future plans, I want to build an amp. Been doing research and figure it will end up being an ESP P3A or AKSA. Maybe that will help in the driver selection? Looks like it will take a while to find all the components for the P3A (but I really like the idea of collecting everything and building it "myself") and I was thinking of building a gainclone kit to listen to the speakers with until I finish the P3A. Then, if it's a good idea, I was going to bi-amp the speakers with the gainclone running the tweets and the P3A running the woofers and use some active crossovers. Of course it will take yet more time to build the XO's..... Sorry, starting to ramble :) Was getting at that perhaps I should not get too crazy on the passive crossovers if I am planning to go active? Then again I may be using them for a long while until I get the other amp and crossovers built so might as well go for good components, and if I do that I want to go higher order perhaps (4th order) and have Linkwitz transforms as well if I need them.

Alright, getting pretty long winded here so I'll try to wrap up. Since I don't have any test equipment I think I'd feel more comfortable perhaps following someone else's footsteps on driver selection and crossover components? I don't mind tweaking the crossover points to fit my room, but I'm not sure I'm up to designing the crossovers from scratch at this point and get a seemless integration bewteen drivers.

So, I'd appreciate any pointers for a guy starting out, and especially appreciate links or correspondence with drivers, volumes and crossover designs. I don't need box dimensions, how to fabricate, etc, just a volume to shoot for as I can calculate the rest. Please feel feel to tell me why I should go ported instead of sealed also :)

Many thanks,

Mike
 
Alright, getting pretty long winded here so I'll try to wrap up. Since I don't have any test equipment I think I'd feel more comfortable perhaps following someone else's footsteps on driver selection and crossover components? I don't mind tweaking the crossover points to fit my room, but I'm not sure I'm up to designing the crossovers from scratch at this point and get a seemless integration bewteen drivers.

Wow! You are a true rarity - a DIY newebie who realizes his limitations! Normally first timers choose the 2 or 3 most expensive or fetishized drivers, and want to use them with a stock or textbook crossover. Your approach is sound, stick to a proven design and build it as specified, if you tweak anything make it the enclosure IMO. You can always mount the crossover externally for tweaking later if/when you understand what all the parts are doing. Here's a few links to start you off, some are kit vendors, others are just diyers who publish their designs:

www.zaphaudio.com
www.murphyblaster.com
www.creativesound.ca
www.madisound.com
www.northcreekmusic.com
www.selahaudio.com
www.theaudioworx.com
www.ellisaudio.com
http://www.partsexpress.com/projectshowcase/homeaudio.html

If you just want a 2 way floorstander or bookshelf, there are going to be a huge amount of options.
 

tktran

Disabled Account
2003-03-17 4:30 am
Perth
kram0.com
I'm usually the argumentative type, but I second everything morbo said. Good advice.

Here are some more links:

DIY plans free for personal use:
http://home1.stofanet.dk/troels.gravesen/
http://home.hetnet.nl/~geenius/
http://www.knology.net/~wesnor/
(previously mentioned)
http://www.zaphaudio.com
http://www.murphyblaster.com

A potential problem is that now you've got TOO many options, whereas previously you had none. :)

This is when you'll probably want to ask people what they think of particular speakers, either by direct email for via the forums.

I've found the following forums very useful:
www.htguide.com
www.madisound.com
www.diyaudio.com
www.partsexpress.com

Personally, I use the ESP P3A with the "TroelAc Response 2.95" In medium sized rooms that are well furnished (carpets, drapes, soft furnishing) with placement away from walls, they sound excellent, and really sing!

I also built the Zaph Audio SEAS All Metal System, in floorstanding guise, and have had Dan Wesnor's Ella over at my place for a listen. All very good systems, with slightly different strong/weaks points.

I've also heard a Vifa P17/D25 designed by Dennis Murphy, but in entirely different setting and foreign source and amplifiers, so I'd hesitate to make a comparison.

If you'd like to know more, just ask, pop me an email, or visit my website.

Good luck, and have fun!
 
Build a GC by all means but it's not a fill in amp until you build something else. The sonics with a GC will surprise you and I liked it so much better than the P3A. The AKSA is in another league... very yummy and very special.

Yes, I've built them all with the AKSA in the main system and a GC in a secondary system with the P3A used in a test system and tunes for the workshop. I'm not knocking the P3A as it's a very honest design with good sound, but it just didn't do it for me. All a matter of taste.... one person's wine is another's poison and etc.

Your approach is very good to find the right speaker and you'll end up with something very good.

With the music you listen to, a vented would be better to get a lower F3 for use with out a sub. Do a search and there's plenty of threads on the pros and cons of sealed or vented.

Happy building.
 
re systems

There is an article on Rod Elliots site that I wrote called, "satellites and subs: the QB5 alignments". This points out that one of the major limitations of the cheap and simple satellite plus subwoofer system is that if you use a sealed box two way satellite with the usual 6-6.5 inch driver crossing over at around 80Hz, and 3kHz., you push the driver into quite serious non linear distortion at levels far below the standard 90db. with 20db. headroom spec. for a hi fi system, and since all of the distortion products fall in the upper bass lower midrange they are very audible.
A very good bang for your buck solution to this is to use a QB5 reflex alignment, and a suitable high pass filter. In a typical case the Vifa P17WJ has its excursion limited acoustic output capability increased by around 40 times, leading to a pair of these drivers being able to produce 110db. peaks without approaching their linear excursion limit, the difference this makes to the cleanliness of the sound needs to be heard to be appreciated.
The major drawback with this scheme is the anti port zealots that seem to hold sway in some audio circles these days, and who will no doubt declaim long and loud on the evils of ports.
A thing that continually amuses me is that audio types will dismiss as unsatisfactory an amplifier that produces more than a few thousandths of a percent of distortion, and yet happily drive a louspeaker system producing 20% distortion with it, whist claiming they can hear the lower superior performance of their pet amplifier, needless to say I am skeptical.
 

tktran

Disabled Account
2003-03-17 4:30 am
Perth
kram0.com
I agree with Rabbitz, amps can make a significant difference.

I had a NAD C320 that, on it's own, I thought was great. When compared to the P3A is sounded slightly warm and fuzzy in the midrange, with restricted lateral soundstage and mid-bass hump. I thought this meant it was 'inferior', so I promptly sold the C320.

I posted these findings on Madisound, and no-one seemed to have that impression of the C320.

So if I consider the flip side of the coin- in relation to the C320, the P3A has an expanded soundstage, clearer midrange and brighter treble. Now it sounds marvellous with my TroelAc Response 2.95.

But when I hooked up the ZaphAudio All Metal System, it immediately apparent that it was slightly bright. I thought "There must be something wrong with my new speakers"- after all, I hadn't followed John's plans exactly. :whazzat:

When it came for the P3A to go back to the ProAclones, I plugged up another amp to the "All Metal System." What the??! Suddenly the brightness was gone. Articulate midrange without any hint brightness, or as my partner called it- "the slightly metallic sound"

I always thought that an excellent amp will sound good with any excellent speaker and excellent CD player. But of course, how your stereo system sounds depends on all three, as well as room acoustics.

I hate to say it, but it seems to me now that system "synergy" is actually important- an amp that sounds excellent with one system may not sound good with another. The P3A is a stellar amp with the TroelAc Response 2.95, and I know at least one person who uses the P3A with the acclaimed Linkwitz Orion.

But when partnered with the All Metal System I found it unenjoyable.

beady,

The GC is a good amp, and the P3A may be an upgrade, sidestep or downgrade, but it's hard to tell without building both and listening.

As for me, I was looking to buy a budget Rotel amp for the All Metal System, but perhaps I should be looking for a NAD C370, which is what John was using when he fine tuned his crossover and concluded his design.
 
Re: re systems

rcw said:
The major drawback with this scheme is the anti port zealots that seem to hold sway in some audio circles these days, and who will no doubt declaim long and loud on the evils of ports.
A thing that continually amuses me is that audio types will dismiss as unsatisfactory an amplifier that produces more than a few thousandths of a percent of distortion, and yet happily drive a louspeaker system producing 20% distortion with it, whist claiming they can hear the lower superior performance of their pet amplifier, needless to say I am skeptical.

Robert, there's no need for that sort of tone as this thread has been running fine with out that..... BTW, I like ported speakers. Everyone is entitled to their opinion and comments and I'm greatful that they do, as life would be too boring. If you can't hear the difference between amplifiers, that's fine, but don't ridicule those that state they can. They are doing it on the basis of what they hear and not forming an opinion from some measuring equipment.... they're happy and that's all that matters. All the amps I've found appealing do have higher levels of distortion and harmonics... maybe the tube guys know something besides watching something glow in the dark. I've heard amps with extremely low levels of distortion and found them too analytical..... not presenting the emotion and involvement of music . I think we need a bit less skepticism these days as it's up to the DIYer to try and form their own opinion. I know where the skepticism comes from, but leave it at that forum.

tktran said:
I always thought that an excellent amp will sound good with any excellent speaker and excellent CD player. But of course, how your stereo system sounds depends on all three, as well as room acoustics.

I hate to say it, but it seems to me now that system "synergy" is actually important- an amp that sounds excellent with one system may not sound good with another. The P3A is a stellar amp with the TroelAc Response 2.95, and I know at least one person who uses the P3A with the acclaimed Linkwitz Orion.

Spot on.... system matching is so important and a black art to get it right. If any one has a formula for matching, please pass it on :D The GC when used in one system, sounded er... quite ordinary, but in another hmmmm... great.

Cheers
 
Wow, thanks for all the quick responses! Looks like it will take me quite a bit of time to go through all those links to see what is there.

Guess I'll have to do some more research on the gainclones; from what I had read I "thought" they didn't sound as good as the P3A's and AKSA's. I was thinking of buying and building one of the gainclone kits from ww.chipamp.com, is this a good place to buy from with quality components?

rcw, the QB5 alignment sounds interesting and worth looking into more. Googling, I found some other posts by you on the subject from last year, but other than that there does not appear to be a lot of information out there to find. I certainly didn't see any integrated designs for running a woofer like that with a tweeter matched to it that I might start out following for my project. Perhaps you could shed more light on the subject or point me in the right direction?

Unfortunately I am one of those ppl who likes to check out all the alternatives and really contemplate what I want to do before I make a decision, so I probably won't be choosing drivers or amps in the immediate future. Don't take that as me not appreciating the comments and information though, as I do :) Also, my initial ideas usually take a while to finalize, and go through a couple of intermediate stages, but that's part of the fun in getting something "just right" that you really like, right?
 
beady said:
Guess I'll have to do some more research on the gainclones; from what I had read I "thought" they didn't sound as good as the P3A's and AKSA's. I was thinking of buying and building one of the gainclone kits from ww.chipamp.com, is this a good place to buy from with quality components?

It's a good valued GC kit with good components. I had a kit given to me and wasn't expecting much, a chip and a few resistors and caps I thought pfft, and was shocked and blown away with it. What I said about amps is only my opinion any way. Build them and make up your own mind... all part of the fun... and don't listen to an old fart like me :D

If you want to know a bit more about the AKSA, have a look at their forum.... lot of happy builders and owners over there.
http://www.audiocircle.com/circles/viewforum.php?f=19&sid=bd5bedd728249c6e386afd7adacc4bbe
 
Unfortunately I am one of those ppl who likes to check out all the alternatives and really contemplate what I want to do before I make a decision, so I probably won't be choosing drivers or amps in the immediate future. Don't take that as me not appreciating the comments and information though, as I do :) Also, my initial ideas usually take a while to finalize, and go through a couple of intermediate stages, but that's part of the fun in getting something "just right" that you really like, right?

Makes perfect sense, I am the same way. Just beware of analysis paralysis, there are few bad choices out there, and its very easy to obsess over minutae.

rcw, I am also interested in your article, as I have arrived at something similar just from fooling around with vented speakers and DSP... though I've never tried adding a sub, just used it to make a increase power handling in a vented speaker. One thing I do wonder though, is how you go about bringing in the subwoofer with a symmetrical slope that matches the rolloff of the satellite?
 
Hi beady,

To cover all alternatives, read through linkwitzlab.com and think about his Orion speaker as a multi-stage project. Very few speakers have gotten better reviews.

You could build the MT 2-way first and cross to your monopole sub at 120Hz. Not an ideal setup, but acceptable first step to audio heaven. I believe Linkwitz shows both passive and active xovers for the MT. Later you can build some GC amps, a stereo pair of dipole woofers, and the active crossover.
 
on several things

The matching between the subwoofer upper roll off and the satellites is in fact affected by the room and the relative positions of the enclosures more than anything else, and in different rooms a slight under or overlap of crossover frequencies can smooth out irregularities.
On the subject of woofer and tweeter matching Beady, in an AES paper Bullock showed that for an arbitrary woofer and tweeter the stock crossover design that gives the closest to an ideal characteristic is the Linkwitz-Riley.
This is an important result for diy because people generally get what is affordable and available, and if new to the subject are sold one off the stock passive crossovers that consist of a few cheap components and don't work very well at all except by pure chance.
There is a lot to be said for a fourth order electronic L-R crossover and bi amping because although building the various electronic bits can be tedious the result is almost certain to be as good as ready built commercial systems costing very much more. A custom designed crossover does give better measured performance but you need considerable expertise to design a good one. One advantage is that if you use 2x50Watt single chip amps per box it is effectively a 150-200Watt single amplifier, and is considerably cheaper and easier to build than one of those.
Sorry Rabbitz, I just thought I'd have a bit of a go, just to prevent you from becoming too comfortable and compliasant out there in subjectivist territory.
 
Hi Beady,

Welcome to the hobby! One thing i've learned as I've been reading (and experimenting, but mostly reading ) is that some of the best drivers take some involved crossovers to get the best sound.

Metal and composite fiber (kevlar, carbon fiber, etc) cones tend to work extremely well within their range, but at higher frequencies they "break up", causing all sorts of high frequency garbage that needs a special crossover to filter out. The point of me telling you this is- if you want to find $350 worth of drivers, it wouldn't be hard to spend another $200 for crossovers!

Another problem to consider with a 2-way system is that a 6 or 7 inch driver is much more directional at high frequency than a little dome tweeter. This can cause a problem when you're listening off-axis, and it changes the character of the sound that's reflected from your walls, floor, and ceiling.

Another good link to learn more about the issues involved in speaker design is:

http://linkwitzlab.com

Also, if you're interested in transmission-line enclosures, don't forget to check out:

http://quarter-wave.com
http://t-linespeakers.org/

I think that one of the better systems you could build near your budget might be the Modula MTM described at htguide.com/forum in the "mission possible" section, but built into a Seas "Thor" style transmission line enclosure (which you can see plans for at madisound.com). Please keep in mind that transmission line enclosures take some simulation and tweeking to get right- the above links can tell you a great deal about that, and somebody on this forum would probably be willing to run a mathcad simulation for you can't get a copy of mathcad.

Overall, if you're comfortable with your woodworking skills and you want to experiment with it, I think that transmission lines and horns are two areas that you could explore.

Oh, and don't forget http://gainclone.com for forums regarding gainclones.

Joe

PS- sorry if someone beat me to some of these, I typed this response this morning before work, and didn't get a chance to hit "submit" until I got home at night.
 
Well I looked at all the links that everyone supplied. Thanks *very* much, some of those were excellent and just the sort of thing I was looking for!

Linesource, that speaker does sound like it would sound spectacular, but, I don't see SWMBO being happy about speakers sitting several feet from the walls in the den :) Perhaps someday if I have a dedicated listening room I could move in that direction.

rcw, can a Linkwitz-transform circuit be added to any driver to increase power handling, etc? I haven't digested it all to that level yet to be honest. I will have to spend some time reading up on the transform and how to incorporate it I guess.

joe, yes I figured I'd have to spend a fair amount for good crossover components. I guess that's whay I was trying to get a feel for what I need to spend for decent drivers; the crossover costs probably won't change much, right? To be honest I was leaning towards a 6" or 7" 2-way smallish floorstanding enclosure. I was the tweeter time-aligned with the mid, so I will do a sloped baffle. I *thought* aligning the tweeter physically farther back from the mid was how to time-align, but doing research some info seemed to show you could do this in the crossover network also/instead? Can anyone shed light on that? I want to make sure I have enough bass (mid-bass? 50-80Hz-ish?) and I am concerned that a 5.25" driver won't cut it for me. I've never listened to any high-end speakers so I really have no frame of reference to go by. I think I saw a design or two using two 5" or 5.25" drivers to boost efficienct and bass output. Perhaps in order to increase off-axis response I should seriously consider that idea? Maybe have have a vented alignment with one or both 5" drivers and a Linkwitz transform to really up the output as much as possible while keeping great sound quality?

Thanks for the help so far everyone, and hope I'm not asking too many "dumb" questions.

Mike
 
re linkwitz transform

The Linkwitz transform has no effect upon power handling as it is applied to a sealed box that has a constant "kp" that is in the region of 0.8-.085, for all sealed boxes from very overdamped to grossly underdamped.
It is very usefull for making minimum sized subwoofers, but the driver needs to have plenty of excursion and power handling, and will produce large amounts of distortion unless it has compensation for flux modulation and d.c. offset.
 
Beady IMHO we are starting to get to the point of too much technical information for a beginner on this thread - things have gone off topic somewhat and I apologize for my part in that. You wanted some good 2way designs to build - I would say stick with your original plan, build one of the designs in the links.

As for the time alignment thing, it can be done either physically (like you described), or in the crossover design by delaying the tweeter's output. If it is already compensated for in the crossover (ie the design you see is not slanted), then you should NOT slope the baffle, it will make it sound worse.

The Linkwitz transform is not something you will likely need to worry about on a 6 or 7" 2 way.
 
morbo,

Technical is good, I'm a mechanical engineer so I like technical information :) The trick is getting enough information at a deep enough level so that I can make meaningful decisions so I won't regret them later.

Is there a certain part of the crossover circuit that determines the phase relationship? Or is it just the overall LCR circuit and the relationships in the circuit? Ugh, I hated LCR circuit analysis in school, lol.

I'm trying to leanr some "rules of thumb" as I go along here. So far what I think I know is:

1) Smaller drivers have better off-axis response. (larger "sweet spot"?)

2) You want to go for the lowest Fs on a tweeter that you can afford for a lower crossover point. Fs of 750 is good, 500 is better.

3) Vifa's have great, smooth midrage reproduction and can be crossed over at a higher point so you can move the XO point farther away from the critical midrange.

4) Dayton's aren't quite as smooth and don't play as high but have much better bass capabilities.

5) a 5-5.5" driver can be crossed over up to 2.5 KHz and sound good..

The ProAc 2.5 clone looks like it gets rave reviews, but the driver doesn't seem to be available anymore? Looks like that might have the bass response I think I'll be happy with. Is there a substitute driver that will work as well that ppl. have used sucessfully?

Thanks,

Mike
 
OK well if you don't mind getting a bit more technical then no problem there. Just remember that most of these things have been considered far more thoroughly in the designs you will be looking at than in our discussion here. Like with any engineering problem, the general observations you are drawing here are rules of thumb and nothing more, in many cases they present very solvable engineering problems that the designers of above systems have addressed effectively.


1) Smaller drivers have better off-axis response. (larger "sweet spot"?)

To some extent, however this is only true at higher frequencies. It would be more accurate to say, a larger driver will become more directive (also called 'beaming', 'rolling-off off axis' etc) at a lower frequency. Whether you want the final speaker to have a relatively wide or narrow directivity (different schools of thought here), you always want to cross your drivers together in an area where their directivity is similar, so that you don't have a different off-axis response at the xo frequency. This is what people mean when they say 'flat power resonse', power response being the sum of on and off axis response.

2) You want to go for the lowest Fs on a tweeter that you can afford for a lower crossover point. Fs of 750 is good, 500 is better.

This is too general, a low Fs is not a guarantee of a good tweeter, it just means that *all else being equal* you can cross the tweeter lower. In a 2 way with a 7" or larger driver, there is a big emphasis on being able to cross the tweeter lower, particularly if the midwoofer is 'stiff' coned.

3) Vifa's have great, smooth midrage reproduction and can be crossed over at a higher point so you can move the XO point farther away from the critical midrange.

Vifa makes many drivers, many of which may have great smooth midrange reproduction. They make a lot of drivers, from entry-level to near state of the art. The higher XO point has nothing to do with vifa per se, it is a general characteristic of relatively 'soft' cone materials like polypropylene and paper, as opposed to more rigid cone materials like kevlar, carbon fibre, aluminum, and magnesium. More on rigid cone drivers in the next point.

4) Dayton's aren't quite as smooth and don't play as high but have much better bass capabilities.

Dayton makes a huge variety of drivers that cannot be generalized this way. From some very cheap and low quality drivers, to some near state of the art drivers like the RS series. Again, how high they can play is a function of cone material and dispersion (discussed above) more than the vendor.

Now - what you mentioned about Dayton's not being able to play high was probably a reference to their aluminum cone drivers - but applies in general to most rigid cone drivers. It is also not even entirely true to say that rigid cone drivers cannot play high - they will produce sound into the high frequencies, but most will start to 'break up' (ie behave non-pistonically) or 'ring like a bell' beyond some frequency. This can be addressed by using a low and/or steep crossover to make sure the driver is not playing those frequencies at any significant level. It is also possible in some cases (ie Seas Excel magnesium drivers) where the 'break up' is very limited in banwidth, to use a notch filter to keep it from being excited. Stiff coned drivers in general probably have the most potential for behaving like an 'ideal piston', but they are also more difficult to work with because of the issues above. That is about where my knowledge runs out on this subject, but I'm sure others can chime in if more detail is needed.

One other thing - there is more to the sound and quality of a driver than the cone material - motor strenght and linearity are important, as is the surround material, even glue. You can find discussions on transducer design here with a search, frankly they are beyond me at this point so I won't discuss them more. I am satisfied knowing that in my price range (read: less than $100 per driver), all drivers are compromised in one aspect or another, and I should choose the one whose combination of strengths and weaknesses of my application, in my price range. Personally, I find drivers with relatively advanced motor systems (ie dayton RS series, adire XBL drivers, peerless CC and CSX, seas, some vifas) to offer the best bang-for-my-buck.

Finally, I should mention again that all of this will be considered by a good designer, the kits/designs you are likely to look at have chosen their compromises and worked around them already, so you don't need to worry much about these issues in them, though they are good to know in general.

5) a 5-5.5" driver can be crossed over up to 2.5 KHz and sound good..

In general this is true, though I'm sure there are quite a few exceptions.
 

tktran

Disabled Account
2003-03-17 4:30 am
Perth
kram0.com
The ProAc 2.5 clone looks like it gets rave reviews, but the driver doesn't seem to be available anymore? Looks like that might have the bass response I think I'll be happy with. Is there a substitute driver that will work as well that ppl. have used sucessfully?

Thanks,

Mike
Yes drivers are still available- coming in at around US$400 for the SS 8535-00 and 8513-00 for the original clone.

I'm trying to leanr some "rules of thumb" as I go along here. So far what I think I know is

As with all rules of thumb, you need to beware- and you start reading as "Generally..." or "Often..."
 
Haha, so basically thinking I know something is a dangerous thing :)

Do any of you guys have an opinion on the ProAc 2.5 clone? Looks like it might be just the ticket for me. The larger driver should provide the bass response that I (think I) want, and the design seems to get really good reviews for the most part.

tktran, thanks for pointing out that the drivers are still available; I guess I didn't look at enough links after finding a site saying it was discontinued, sorry. $400 is still close enough to my initial guesstimate of $350 for drivers :) Sure good XO parts will up the cost, but I've had my last set of speakers for about 13 years, so what's a few extra hundred bucks on something I'll be enjoying for over a decade?

Please comment on the ProAc 2.5 clone, good or bad.

Thanks,

Mike