I bought a set of the WR125S 4.5 inch full range drivers.

Just completed these, and wanted to mention that I am SO happy with the sound that these little buggers create in my room.

I first received my set of these, during the October sale that CSS (www.creativesound.ca) had, during their initial run.  I boxed them up in cardboard, to break them in, and get a sense for what they could do.  They sounded surprisingly good, given that the enclosure was trash. I gave them about 100 hours of break in, happily listening to those cardboard boxes, although the bass was lacking, and the boxes droned pretty bad…

I sat down at my PC with WinISD, and began looking at plots.  Waste of time in the end, the 0.3 foot enclosure that is recommended, ported to anywhere between 55 and 70Hz is great for this driver.

Conspired to build my own narrow baffle, deep enclosure, since that shape floats my canoe.  Spent the last couple of weeks measuring, planning, and cutting some 0.75 inch mdf and Baltic Birch plywood panels.  Then spent some evenings and AM's gluing and clamping.  Then came the fun with the silicone, and leaving my powder room fan running all night...

Long story short, the boxes are completed (the exterior finish will have to wait since it is a little too chilly in the garage for painting at the moment in Toronto, ON, Canada) and are again running in my basement, in my present system.

Nakamichi CD4, Monarchy DIP, Bolder Mensa, B&K pre/pro, Bolder modded Teac tripath amp, Bolder M-80 IC, and speaker cables, and my DIY CSS speakers.

Mids are what really did it for me, even in the cardboard boxes - this is still excellent.  Highs are nice, clean and clear, and missing little to these 34 year old ears.  Bass is what shocks me.  I have listened to my Totem Rokk in this room before (14x17 with one of the 17 foot sides open to a hall and laundry room – this is a tough room to pressurize with bass, even using my 12 inch sub with 300w digital amp) and their 5.25 woofer did not cut it without the sub.  I have turned off the sub, and am listening to these little 4.5 inchers belt it out, all on their own.  I do use a sub for movies, and often for listening, but what I am getting at, is that these little guys push out way more than I would have expected, and are satisfying on their own – I can only imagine what they would sound like, in a smaller, more conventionally shaped room.

Overall, fantastic coherency, and engaging sound, when paired with my Bolder Teac tripath amp.

Thanks to Kevin, and CSS for making these great little drivers available, at real world pricing, and for delivery fantastic sound.

More to come, as things develop.

They really don't need a baffle step.   The response is designed to be rising from the traditional 400-500HZ point so it doesn't need the additional network.   In fact.... most of the time these sound best without any crossover.   Even in the MT version we are releasing soon we designed the crossover on the tweeter only.   The CS125 is running full range with zero components in it's path.  

I don't do this because I'm a purist.   It just sounds really good that way although the response shows a slight hump at 10K on-axis.   Move 5-10 degrees off-axis and all is good though and the crossover is extremely simple.

This is definitely a good looking driver, and I think it just might be the one to beat, Jordan included, which though fantastic sounding, are not the most dynamic drivers, and are now twice the price of the new 125.

I foresee a coming stream of excellent designs, -the specs are great, and it is a tough little bugger. I am kinda stuck on the idea of  2 X 16 Ohms, gaining a 2-4 db lift apparently, and dipole, add tweeter to taste. Or one of the GM inspired pipes for the Jordan, like I have in the bedroom, the amount of sound and bass Greg milks out of that thing is like 1+1=9, and I would bet the 125 would be   even better, louder, more bass  If you want to see what I mean, go to www.quarter-wave.com to the Gallery and scroll down to Jay Fisher's design, which is identical to my own. I am betting this pipe design, with the XBL 125, would be even better. Watch out for this one and gets yours today KevinP definitely has a handle on something very special here.

Pics for those interested - please forgive the "unfinished" nature of the speakers - it is too cold out right now to put any real finish on them, so they will remain "natural" for the next couple of months.

In the Spring I will route off the corners of the boxes, and apply a finish.

I am in the process of planning a matching center channel, since my Totems (seen in the final shot) are not video shielded, and foul my old school CRT Vega TV...

Now when you guys talk about dipole, you simply mean a driver on the front and rear of the enclosure - not open baffle or anything ala Linkwitz Orion right?

Another thing - do you wire the two drivers in phase or out of phase in this implementation?

Occam, the link and pix dont happen...

Until then, new in from Sim City is a really interesting idea for the 125 in a ML TQWT, specs down to 40Hz flat   if the units are consistent. The idea is to double up on the drivers, CSA, and use vents if you can make em.

L = 49.55"
Zd = 33.68" for the first driver
Zp = 47.55"
SO = 0.763"^2  it comes to a point
SL = 60.265"^2
Rp = 1"
Lp = 3"

with .2lb stuffing at the vent to damp out Fb. A very smooth looking design, courtesy of GM

This would be a cute little devil, about 8.5X7 at the base. Kevin, take a  look at this one

That one is just grist for the mill. T'would make a great pipe though.

Has anyone calc'd the 125 for baffle size and curve, yet? 200Hz would be my target Fs...

I wouldn't recommend them for dipole use as a bass driver.  Maybe midrange but you need to move MUCH more air than these little 4" drivers are capable of doing.   The Sd just isn't there even though these are little strokers with 12mm PP excursion.

Also... tuning them that low in a TL is expecting too much of the driver.   You won't get enough SPL that low to really produce satisfying output.   Your much better off following the ported alignment and subjectively it sounds like it has more bass than the TL even though it doesn't measure as deep.   Remember the Fletcher Munsun curves.   You need some SPL before the lower frequencies start to become noticable.   The 4" TL just doesn't have the Vd to produce the lowest frequencies at high enough SPLs.

If you guys want bass you really need to look at the Extremis.   I'll have it on the site soon and the MT based kits are about ready to roll.   I was over in Seattle yesterday at Dan's place listening to the pair we are showing at CES.   They are just incredible and I think these are going to be some of the best monitor speakers on the market at ANY price.   The 6" Extremis has the same magic midrange & clarity that the CS125 does yet has the output to reach REALLY low.   Low enough in a small 0.75 ft^3 box to reach into the mid-20s in-room with AUTHORITY.   Absolutely no sub required for 2-channel chores.   We are using the Usher 9950-C tweeter which I choose for the kit versions and I must say that it is an excellent tweeter to match with the best 6" driver on the market.    The combination is incredibly smooth and detailed with dynamics to spare before they even start to think of breaking up.

I'm not sure which MT kit your talking about so I'll give you details on both.


The MT Kit based on the CS125 is designed to work in the Parts Express 0.25ft^3 boxes.   It includes two CS125s, a pair of tweets, crossover components, ports, wire, speaker post etc.....   Basically everything you need to build them minus the wood.   The kit is going to cost $199 plus shipping.   The finished PE cabinets are just around $100/pr so you get a finished speaker with very little work and about $300 out of pocket.

Crossover frequency is around 8.5K and only on the tweeter with a very simple second order network.   The CS125 is run full range without a crossover of any type.

The MT kit based on the Extremis is designed to work in the Parts Express 0.75ft^3 cabinets.   They include everything but the wood as above and the drivers consist of the Extremis & Usher 9950-C (shielded version).  The ports are Precision Port double flared units.   Cost is yet to be finalized as I'm still getting quotes on crossover parts but it is looking like they will come in around $400/pr.   The PE cabinets cost $86 each so the finished speaker cost is gong to land around $570 total cost.

Keep in mind these kits are going to set new standards for measured performance.   There won't be another monitor on the market (same size) that can match it in bandwidth nor measured distortion & on/off-axis performance.    Also power compression is extremely low due to the XBL^2 motors so dynamic range is incredible for this form-factor.   Overall $570 is an incredible price considering they will eat any monitor on the market and I'll be happy to support that with 3rd party measurements once we get rolling.

The crossover point on the Extremis MT is around 2.8K with a Dan Wiggins special 6th order acoustic solution.   The measured frequency response is +/- 1db from about 60HZ-20K.   Of course on the bottom end that measurement is meaningless but that is what they measure on-axis without a room.  The crossover greatly reduces IMD and there is huge amounts of bandwidth overlap in both the tweeter & the Extremis.

We are using a pair of shielded HiVi tweeters.   They only have to cover the very top octave and they just add a little sparkle to the top-end so we didn't see the point in spending huge dollars on the tweeter.   Most people have used the CS125 without a tweeter and been happy so our goal was to just goose the last octave a little.    The HiVi unit is perfectly suited to this purpose and since it is run incredibly conservatively (crossover is about 2.5 octaves above resonance) it never strains.   In fact I'd say that it is responsible for less than 5% of the total output of the speaker.