Semi Active Three Way Speaker Project

[Qwin]

I've never been happy with the three way speakers I have owned in the past, or, baring a couple of exceptions, those that I have heard. I found them sibilant, which I partly put down to the crossover point for mid/ tweeter being generally at 5 to 7kHz. This is at a very sensitive point for reproduction of human voice, as this is where sibilance lies and I was guessing that it might be part of the problem. Two way systems seem to suffer less from sibilance and I attribute this to the crossover point being much lower, at around 3kHz. One afternoon, I tried an experiment and sat an old pair of Tannoy M20 bookshelf speakers on top of my now active Yamaha NS-1000M speakers. I used a 2-way active filter I had, which crossed at 300Hz and fed the 12" Yamaha bass driver the low frequencies and the Tannoys got the higher frequencies, I kept the Tannoys passive crossover in place for mid/upper frequency separation. I was amazed at the results, the Tannoys were great at voices, but now they had a bottom end. This discovery is what kick started this project, my reasoning, when trying to predict what causes the sibilance, could be completely off track, but the results certainly aren't. I started to search for a pair of modern bookshelf speakers that were good with voices and which I could mate with a 12" Woofer or Sub driver. My idea was to use the drivers and crossover from the bookshelf speaker as part of a 3-way Semi Active Project (SAP), in a large sealed enclosure.

http://www.jkwynn.co.uk/Project_Images/SAP/sap_01.JPG

After a lot of searching I settled on the Quad S-1 bookshelf speakers shown above, they got good reviews and I liked them when auditioned, preferring the way they handled midrange, to their larger Quad S-2 sibling. I took them to the MiBO meet and I thought they sounded pretty good in the mid range and top end, with an obvious limitation being the 4” mid/bass for the bottom end. They should do the job for mid and top end and I'll cross over to the 12” bass at 310Hz.

The specifications are as follows:

Description:...................2way Ported
Mid/Bass Driver:.............4" (100mm) Woven Kevlar No D-1100
Treble Driver:.................12 x 45mm True Ribbon Model - Fountek NeoX 1.0
Sensitivity:....................84dB (2.83v@1m)
Peak SPL:......................96dB
Amplifier Power:..............25 - 100W
Nominal Impedance:........8 Ohm
Response:.....................58Hz - 20kHz (+/-3dB)
...................................(Tweeter is actually flat to 40kHz on Fountek's response plot)
X-Over Point:.................3.2kHz
Cabinet Volume:..............6.65L Gross 6.0L Net, Completely filled with stuffing
Cabinet Walls:................16mm
Dimensions:...................H285 x W156 x D240mm (Outside)


http://www.jkwynn.co.uk/Project_Images/SAP/sap_02.JPG

The plan, is to incorporate the Quad drivers and passive crossover, into a sealed chamber within a much larger cabinet, designed for a 12" Woofer. An active x-over will split the signal at around 300Hz and separate amplifiers will power the Bass Driver and the assembly from the Quads. The Quads are a 6.7L ported design, so the T&S parameters of this small mid/bass driver are needed, to calculate the volume of a suitable sealed chamber.
These results were measured for the two drivers.

..........................A....................... ...............................B
Piston Dia:.........83mm................................. ................83mm
SPL:.................84.78dB 1w/1m.....................................84.99 1w/1m
Re:...................3.389 ohm..........................................3.419 ohm
Fs:...................80.08 Hz.............................................82. 1 Hz
Qts:.................0.583........................ ..........................0.583
Qes:.................0.716........................ ..........................0.737
Qms:................3.154......................... .........................2.805
Le:...................0.175 mH (10k).....................................0.176 mH (10k)
M(ms):..............6.00g......................... .........................5.67g
Vas:..................2.707 L...............................................2. 718 L


Using the figures for "A" and maintaining a Qtc of 0.707 this calculates as a Net sealed box volume of 5.8L (without filling) with an F3 of 97.1Hz. This is more than an Octave below my planed crossover frequency and with the active filter having a steep slope (24dB/Octave), this should work well. A sealed box of 4.0L will give a Qtc of 0.755 and an F3 of 97.6Hz. The higher Qtc of the smaller chamber could possibly benefit the mid range, conversely a well stuffed 4 litres will give a virtual volume of up to 4.8L, so there is a lot of scope for manoeuvre with the design of the sealed chamber.

A screen shot of the impedance sweep + T&S parameters for driver "A", can be seen below.






http://www.jkwynn.co.uk/Project_Images/SAP/sap_03.JPG

The impedance plot and T&S parameters for The Quad D-1100 Mid/bass, Driver "A".
Calculated using the Dayton Audio Test System (DATS) software.






http://www.jkwynn.co.uk/Project_Images/SAP/sap_04.JPG

The crossover boards revealed fairly ordinary parts. Chinese MKP caps, ceramic resistors and an Iron cored coil in the bass filter. Better quality parts should help here, so I need to draw the circuit schematic and determine what changes will be made. The Capacitor and Resistor values are printed on the parts, I emailed Quad UK and they were very helpful in supplying the Coil values. All parts were measured from the two boards anyway to check how close they matched the stated values, the coils were very close, some caps were and some were not, resistors were also pretty close.



Stock Crossover Schematic
http://www.jkwynn.co.uk/Project_Images/SAP/Quad_S1_crossover.pdf


Modified Crossover Schematic
http://www.jkwynn.co.uk/Project_Images/SAP/New_crossover_layout.pdf





http://www.jkwynn.co.uk/Project_Images/SAP/sap_07.JPG

The proposed crossover layout and parts are illustrated above.
The Ceramic resistors have been upgraded to Mills wire wound and from 5W to 12W.
The Chinese MKP caps have been replaced with Ansar Supersound MKP.
The Iron core coil has been replaced by a Jantzen Air Core.
The values are unaltered, but the better quality parts are closer to the required figures.
The Bi wire facility has been removed and instead, a Star Grounding scheme has been applied.
These basic upgrades wont create a night and day difference in sound quality, which was already very good. There was however, a slight coarseness/grain audible in the mids/lower treble, the new parts will hopefully remove this.
I suspect the ceramic resistors and cheap caps in the signal path were the main cause of this.

I already have a pair of 1R5 mills resistors and a pair of 6.8uF Ansar Supersound's from my parts bin, these will help reduce the cost of the upgrade.





http://www.jkwynn.co.uk/Project_Images/SAP/sap_08.JPG

The passive crossovers have been completed.
The large coils used were described as 1mH/0.25ohm, I measured them as 1.036mH/0.215ohm.
This worked to my advantage, as when I wound some turns off, to get my desired 0.95mH, it also gave me the exact rdc value I required of 0.2ohm.





http://www.jkwynn.co.uk/Project_Images/SAP/sap_09.JPG

This is my proposal for the 3-way layout. The Quad drivers in their sealed chamber are paired with the 12" Scanspeak 30W/4558T00. This driver is classed as a Subwoofer by Scanspeak, yet some dealers list it as a Woofer. This is because it has a usable range up to 1000Hz, this is way beyond what most true sub drivers achieve, they tend to roll off at a much lower frequency. This is also one and a half octaves above my planned crossover frequency, which is pretty much ideal.
My Yamaha NS-1000M have an F3 of 53Hz in a 50L sealed box. The Scanspeak driver calculates (Qtc 0.707) with F3 of 38Hz in a similar sealed volume. If I keep the foot print dimensions the same, I'll be able to use the 300mm stands I made for the Yamaha's with the new speakers.





http://www.jkwynn.co.uk/Project_Images/SAP/sap_11.JPG

This is my proposed layout for the active crossover/power amp, with its four channels of amplification using Hypex ucD180 modules (180w/4ohm 120w/8ohm). I have kept Left and Right separated, each side having its own Switch Mode Power Supply. The active "KMTech" crossover board for each side is powered by its SMPS aux unregulated output, so a small adjustable regulator board has been inserted for each crossover, to supply the required +/- 12Vdc. I have made provision for an adjustment pot on the Bass output of the crossover to match the bass driver to the mid/tweeter level. The mid/tweeter are 8ohm and only 84dB/1w/1m sensitivity, were as the Bass driver is 4ohm and 89dB/1w/1m. Using identical amp modules, the bass driver should have more output, but it requires more power than a mid/tweeter anyway, my gut feeling is it will still have too much and will require just a small amount of attenuation to match the less efficient mid/tweeter set up. We will have to see if that works out correctly. AC/DC/Signal lines have been kept apart to reduce the chances of interference.
The whole thing fits into a 2U x 300 19" rack case.





http://www.jkwynn.co.uk/Project_Images/SAP/sap_12.JPG

I've completed the lash up from 18mm chipboard, with 18mm MDF baffle. It will test the new crossover and sealed chamber, the chamber is somewhat smaller than the original ported box. I fully stuffed the chamber with fibre glass loft insulation and mounted the crossover on the back for easy access and to duplicate what will happen on the final build. I made a wide baffle to match the width of the design proposed and give a good representation of what it will sound like.





http://www.jkwynn.co.uk/Project_Images/SAP/sap_12A.JPG

The baffle is also the same width as my Yamaha NS-1000M. With the Yamaha's turned upside down and the lash up placed on top, the drivers are spaced similar to my proposal. I have each of the drivers in my active Yamaha's wired separately to its own set of binding posts, without an internal crossover, so the Yamaha's bass driver is borrowed here for the sound test.





http://www.jkwynn.co.uk/Project_Images/SAP/sap_13.JPG

For the first sound test, I'm using my multi channel Nakamichi power Amp. I'm also modifying to suit, my test bed (analogue) active crossover, pictured above. I've swapped out the unregulated KMTech power supply board, for an adjustable regulated PSU from China. I replaced the Chinese caps with Panasonic FC but changed nothing else on the board, these PSU boards are to be used on the final build, so it's a good opportunity to see how they perform.





http://www.jkwynn.co.uk/Project_Images/SAP/sap_13C.JPG

I made a few changes to the KMTech crossover boards, adding bypass caps on the underside, a 0.1uF Ceramic and a 4.7uF Tantalum in parallel, attached to each power pin on the op amps and run to the ground plane of the board. The Red Wima film/foil caps across the +/- pins were tried, but removed, as they degraded the sound IMO. These boards cross at 310hz and I used 1% metal film resistors and Vishay MKP 1837 1% caps. I also converted the single ended input to balanced, by combining the two halves of the balanced input, using the buffer op amp. I had to cut some of the tracks, add alternative paths point to point and solder a couple of additional parts in place, as can be seen. The boards are single ended, but by creating a balanced input, I can feed them straight from my Pre Amp, which runs balanced outputs, it just simplifies the connectivity and it does run very quite when wired this way.





http://www.jkwynn.co.uk/Project_Images/SAP/sap_13A.JPG

I used Burson v5 discrete op amps, which I already had, for the Hi and Lo Pass filters, but I changed the buffer to the Sparkos Labs discrete unit pictured above, this mix gives a better tonal balance to my ears. The crossover PCB has pin outs for dual channel op amps throughout, but the buffer makes use of just one channel. The designer did it this way to keep it simple for DIYers and supplies identical op amps for all three locations in their kits, so you can't get it wrong when fitting them. This is a waste of the unused channel at the buffer though and there is a big difference in the price between dual/single channel discrete units. I opted to use a single channel Sparkos unit for the buffer. This complicated things slightly, as the pin outs are different on a single channel unit, so I modified the dip8 socket as shown below to match the single channel op amp to the dual channel pin out of the board. The unused pin locations on the board are not connected to anything, which allowed me to make this change fairly easily.





http://www.jkwynn.co.uk/Project_Images/SAP/sap_13B.JPG

The modifications to the dip8 sockets are on the underside, so you don't even see them when fitted to the PCB. I had a nagging concern that the unused channel on the stock set up would cause noise, as it is powered up without any input connected, whether it does or not, the mod removes this possibility.

I have around 80 hours on this set up, running it in. There was an initial change at 4 to 5 hours and another major change at around 65 to 70 hours when the mid range fleshed out and the bass got a decent punch. It's sounding pretty damn good now. I'll give it at least 100 hours before giving a final judgement.

[Firebottle]

What a brilliant project Ken :)

Many thanks for posting it in such detail.

:cool:

[brian2957]

Fantastic project , and post Ken . Do you think these will be at the next Nebo . They look great :)

[Qwin]

Thanks Alan.

Brian – I will take the lash up to NEBO or what ever name is decided, but I have a long way to go before they will be finished.

I need to purchase and confirm the suitability of the 12” Scanspeak bass drivers, they look good on paper, but they need to blend seamlessly. Then build the proper cabinets and build the combined 4 channel active filter/power amp in a new case. Many elements have been proven along the way, but it all needs to come together. Available time and funds will dictate the pace, the Scanspeak drivers alone are £400 a pair, plus delivery and I'm seriously considering 24mm furniture grade Birch Ply for the cabinets which is £195 for an 8'x4' sheet. It all adds up.

I made a conscious decision, not to post anything till I was well into the project, but I will give regular updates from now on.

I did all the work completed since the MiBO meet in November, so I have had the pedal to the metal on this one.

[YNWaN]

A very interesting project and, as always, very nicely done. However, I think your premise relating to the cause of sibilance is incorrect. I genuinely have no issue with sibilance exaggeration (bear in mind sibilance is present on many close miked recordings in the first place) and the crossover point between mid and tweeter is as standard on my (three way) NS-1000M's. I would also add that whilst I'm sure the Quad mid/bass driver is good it won't be anything like to the standard of the Yamaha dome you already have.

[Qwin]

Hi Mark

Unfortunately I am VERY sensitive to sibilance, to the point where I have to walk away from what's playing, it destroys the pleasure for me.
The Yammy mid range is very good indeed, clarity and imaging like no other and I did consider building a three way system around it.
What stopped me is availability of parts. So I decided to build a three way using currently available drivers.

The sound I am getting and I'm still not using the correct bass driver, is very good and tonally correct, which is important to me, I want a grand piano to sound like one and not like a cheap Casio keyboard. In this respect and with voices the Quads do a very good job. At the end of the day I am the only person that can judge the system, as my requirements are probably different to most peoples. Also these speakers are not a direct replacement for my Yamaha's, everything I'm learning with this 2-way active crossover will be carried over to my Yamaha's 3-way active crossover.

[farflungstar]

Like you I will very sensitive to sibilance, especially any phase imbalance. It has on occasions driven me to distraction and led to me considering all sorts of fixes until I realised the problem was cart alignment - once my cart was correctly set up the problem disappeared - completely (touch wood).

Adey



Sent from my Aquaris E4.5 using Tapatalk

[RichB]

Fascinating project Ken.

Your dedication to the cause as admirable as ever.

Look forward to hearing your results at NEBO.

[Jimbo]

Interesting project Ken as always. Would very much like to hear the finished article.

Thanks for posting so much detail. Must have been a hard decision to take a scalpel to the little Quads?

[Qwin]

Must have been a hard decision to take a scalpel to the little Quads?

Hi James

I knew the Quads were to be sacrificed before I bought them. I went looking for something specific, read the reviews, then auditioned till I found what I was looking for. I wanted drivers and a crossover that were well matched for voices and acoustic instruments, so the design/development work had already been done for me (lazzy bugger). There is a common trend to use a single sub with a pair of bookshelf speakers, I am augmenting the bookshelves with a pair of woofers, which I prefer. The whole omnidirectional thing doesn't sit well with me. You can feel deep bass and while you can't locate many subs in the room, they are not part of the stereo image either and can sound separate, there is nothing wrong with being able to identify were the bass is coming from, as long as its in the right place. Controversial, I know but I'm not trying to convert anyone to my way of thinking, they will have to judge for themselves, when hearing the end result.

I was not a ribbon tweeter fan, most of the examples I had heard, I didn't like, but some were possibly not true ribbons. The Ruark Crusader III for instance, I preferred the Crusader II that had a soft dome. The Quad Ribbon Tweeter is excellent and is flat from 1500Hz to 40kHz, its actually made by Fountek and they recommend crossing at 2000Hz or more, so the Quad crossover point at 3200Hz is good for this unit.

The end result with this project, will not be to everyone's taste, but it will work for me in my very specific (not ideal) room requirements.

Edit: The Quad cabinets with crossovers are back in the original packaging, so I can always return them to as new, if the project falls flat.

[Qwin]

The lash up now has 132 hours on it and has settled nicely.

The original ported box Quads with their original crossover sounded pretty good, I would not have used them if they didn't.
Mounted on top of my Yamaha's and borrowing their 12" driver for bass duties, they sounded very detailed and revealing, which I like, my last few speakers have been studio monitors and I like this sound. The only criticism I had was maybe a little grain in the upper mids/treble.

The lash up, with a smaller volume sealed box and blue printed crossover with improved parts, borrowed the Yammies bass as before. The result was as I had expected, a very slight improvement, removing the grain from the top end. In addition, it also has a slightly fuller, richer mid range, not as lean as a monitor now and the bass seems tighter/faster than before. I'm guessing the 4" mid/bass is better damped in the smaller sealed box and its contribution to upper bass and the edges of bass notes is crisper and definitely audible.

I'm liking the sound - A LOT - most accurate, distortion free, across the whole frequency range, that I've had.

Initially when I had about 30 hours on the lash up, I was a bit concerned, the sound was not as good as the originals. It lacked body in the mids and was tame in the bass, but this all changed at around 65hrs and the roles were quickly reversed.

So I've proven the mid/treble drivers suitability and passive/active crossover elements, when paired with the Nakamichi Amp and 12" bass from the Yamaha's. The next step is to acquire the Scanspeak bass drivers and compare their performance. The Yammies are a short throw 12" with a paper cone, the Scanspeak are a long throw with aluminium cone, so a bit of a different animal. I'm expecting deep fast bass from their rigid cone, F3 of 38Hz or better, compared with the Yammies F3 of 53Hz. It's the tone and how they blend with the mid range that concerns me, they look great on paper, very flat from 100 to 1000Hz, but I need to hear them in this set up.

A couple of things are going to get in the way now, the next NEBO meet is a cert and possibly a try-out at the Wigwam show. I need to have them in some useable state, so they may stay in the current lash up form till these events have passed. I can purchase the Scanspeak drivers and maybe try them in a makeshift cabinet as an interim stage. I'm not lashing out on decent ply and veneer till the new bass is proven. :)

[sq225917]

Can't help but think a lower resolving mid and tweeter is now ameliorating the previous active XO shortcomings. If a grand piano sounded like a Casio your hifi has issues, other than needing a good subwoofer.

Have you thought about going fully dsp for your yammy xo with six amp channels up them?

[Qwin]

I never said (or meant to imply) my other set up "Sounded" like a Casio.

I was implying I didn't want this set up to sound like a Casio.
A lot of speakers/set ups are poor at reproducing grand piano in my experience, both in timber and especially timing, they just can't keep up.

Forget the Yamaha's folks, they are not related to this project in any way, other than a pair of borrowed 12" woofers, till I can afford the correct ones.

I mention the Yamaha's F3 as a point of reference from this well known sealed box design. It's just something I and others can relate to in terms of my expected bass performance with this current project.

To save confusion, I will not mention the Yamaha's again on this thread.
I will pick up my Active Yamaha thread again, when I have scratched this current itch. :)

[fatmarley]

I will not mention the Yamaha's again on this thread.


Just out of curiosity, did you measure the free-air parameters of the Yamaha woofer in It's enclosure? Just wondered what the QTS (QTC) Is?

[Qwin]

Just out of curiosity, did you measure the free-air parameters of the Yamaha woofer in It's enclosure? Just wondered what the QTS (QTC) Is?

I didn't but if you have a look on Troels Gravesens site, he posted the T&S for the drivers (QTS = 0.28) when he did his renovation project.
Makes an interesting read:
http://www.troelsgravesen.dk/Yamaha-NS1000.htm

[fatmarley]

Interesting driver. It has a very low Fs, low QTS and high sensitivity. According to my sims It would have a QTC of 0.68 In a 50ltr box (assuming no stuffing material), F3 of around 52Hz and a sensitivity of 92.66dB 2.83v/meter.

Subjectively, What does the bass sound like? In my admittedly limited experience, a low QTC speaker sounds a bit too lean and lacking punch for my tastes (This Is assuming Troels has measured the T/S parameters correctly - VAS can be tricky to get right)

[Qwin]

Interesting driver. It has a very low Fs, low QTS and high sensitivity. According to my sims It would have a QTC of 0.68 In a 50ltr box (assuming no stuffing material), F3 of around 52Hz and a sensitivity of 92.66dB 2.83v/meter.

Subjectively, What does the bass sound like? In my admittedly limited experience, a low QTC speaker sounds a bit too lean and lacking punch for my tastes (This Is assuming Troels has measured the T/S parameters correctly - VAS can be tricky to get right)

I don't agree with everything Troels does, but in this instance I think his measured results are accurate, and his findings in general regarding the NS-1000M match my own impressions. The 50L you calculate matches what Troels came up with and matches the volume of the Yammies cabinet. The F3 you calculated matches his findings and also those published by Yamaha in the user leaflet. He says "there isn't much bass below 50Hz" it may plot this way, it does fall off, but I find in the average living room, like mine, there is significant bass reinforcement/room lift. With the gentle roll off associated with a sealed enclosure this means it actually sounds quite deep. I have listened to test tones and 30Hz is still quite present, but at about a third of the output level of 60Hz. As far as punch goes, this tends to be upper bass anyway and is even effected by the mid range, I find they give plenty of punch and slam, rim shots being particularly sharp and realistic. Its only when you get one of those rare droning deep notes that you notice any shortcomings. Bass was as good as my Celestian 66's in my living room, but in a much larger room the 66's still sounded big and powerfull, where as the Yammies lost their presence at the low end.

I want to keep on topic, so if you want to talk any more about the Yamaha's move it over to my Yamaha thread here:
http://theartofsound.net/forum/showthread.php?36385-Yamaha-NS1000M-Tweaks :)

[Qwin]

The Scanspeak 12" bass drivers (30W/4558T00) arrived, Scalford show halted progress, but back on track and hopefully ready in a rough form for NEBO 8. They are fairly substantial drivers with cast alloy frame/basket and a large magnet.

http://www.jkwynn.co.uk/Project_Images/SAP/sap_14.JPG

I just used a library shot, but this is how they come.
I built some 55L sealed test cabinets, this volume gives a QTC of 0.707 and an f3 of around 36/38Hz.




http://www.jkwynn.co.uk/Project_Images/SAP/sap_14A.JPG

I used 18mm chipboard for the construction of this temporary evaluation cabinet, with 18mm MDF for the front baffle and internal brace. All joints were rebated with a router for extra strength and the whole thing was glued without the use of screws or dowels. I used four cargo straps to pull it all up tight while the glue set.




http://www.jkwynn.co.uk/Project_Images/SAP/sap_14B.JPG

Driver fits well and all joints pulled up without gaps. I used a generous amount of fibre glass loft insulation to loosely stuff the cabinet.
Need to get some hours on them now, before evaluating their performance.

[Macca]

Looks pretty serious there, Can't wait to hear them.

[Qwin]

Looks pretty serious there, Can't wait to hear them.

Me too!

I teamed the Quad mid/tweeter with the 12" bass unit, borrowed from Yamaha the NS-1000m, for the Scalford show and they worked quite well together.
The room was one of the worst in the place acoustically, but they still managed a decent performance. I'm hoping the Scanspeak will work just as good and give some extra depth to the bass. Still working on the second cabinet, but they will be finished with a reasonable number of hours run in for NEBO 8.

[JohnJo]

What a cool project Ken, don't know how I missed this thread before now.

Those Scanspeak drivers look to be proper quality items - they look like paper cones but are actually aluminium :scratch:

Looking forward to hearing your findings.

I really admire people with skills for this sort of work :)

[Qwin]

Yep, Aluminium cones.

They are designed for use as a Sub, but unlike most Sub drivers have a ruler flat response up to 1000Hz, which is proper woofer territory.
They have an Fs of 17Hz and Peak excursion of 56mm (25mm linear) so will shift some air. Several dealers list them as woofers and Troels Grevesen has used them in three way designs with good results, so they are in the middle of these classes. I like sealed bass, I feel it works better than ported in my less than ideal room, these drivers are designed for sealed and will go significantly lower than my Yamaha's in a similar size cabinet, which is about as big as I can accommodate.

Being able to make stuff, and I'm no expert, is all part of this great hobby, I have several projects going at the moment that are all inter-related, the findings from each will hopefully come together in an end solution which meets my needs. One of the side projects is that I have taken the plunge and gone for an active digital crossover solution. I have ordered the DLCP system from Hypex and currently waiting delivery of the crossover/SMPS boards. I looked at the miniDSP 4x10HD but favoured the Hypex, as the analogue input is supposed to be better and I listen to a lot of vinyl. Also it is a better over all solution for me, as Hypex class-D amplification can be integrated into the set up and the DSP board can run off the Aux output on the amplifier SMPS. I have drawn up a scheme with the DSP, two SMPS and six UcD180HG amp modules, that fits in a 2U 19" case approx 300mm deep and this is what will run my 3 way speakers. The flexibility of digital will allow me to easily experiment with different mid/tweeter combinations. The complete Hypex system is an integrated digital pre amp, digital crossover and 6 channel 180w power amp in one box, with plenty of digital and balanced analogue inputs, ticks a lot of boxes for me.
You can see the layout here:
http://www.jkwynn.co.uk/DLCP_HTML/DLCP_01.html

[Qwin]

http://www.jkwynn.co.uk/Project_Images/SAP/sap_14C.JPG

Finished the second test cabinet and still running them in, one thing, there is bass a plenty. The next stage is to build the DSP/Amp as I have taken the plunge and decided to go digital. I have started a separate thread for the DSP/Amp here:
http://theartofsound.net/forum/showthread.php?51046-Hypex-DLCP-(DSP)-with-6-Channel-UcD-Amp-Project

[JohnJo]

Looking good for test cabs Ken!

[Qwin]

You have to make sealed bass cabinets, even temporary test cabinets, fairly robust, or you won't hear what they are capable of.
They will just shake rattle and roll or worse leak and make farting noises.
Slapping a coat of satin Black on everything with a roller covers a multitude of sins and looks tidy enough to use for a while. :eyebrows:

My local wood merchant supplied all the chipboard and MDF, cut exactly to size, for £13.70 for the pair.

All I did was the routing and glue it together, with a few captive T-Nuts for securing the drivers.

[Qwin]

Well I have 100hrs on them as a pair.

I wasn't really sure about running in drivers, as having much effect, I know there are firm believers/disbelievers, both from the user and manufacturing front.

Previously, when running in smaller drivers, I noticed a very small change early on and on a complete speaker, I noticed later changes, that could be put down to cross over burn in as much as anything.

That said, I have noticed changes as these 12 inchers got to 60-80hrs. I have them playing around 15hrs a day, mostly using Radio 1X, not my usual choice, but as there is a lot of bass content, it got the cones moving. They mostly played to themselves while I was out, but each evening I played my usual selection of test albums on CD/Vinyl. I initially had to attenuate the mid/tweeter a lot, at roughly 60 hours I had to reduce the attenuation and further at around 80hrs, as the balance seemed to change, having too much bass. I don't think this was me getting used to the sound of the new drivers. I have very specific taste, in how I like the tonal balance on certain tracks and to keep this balance I had to adjust the output level on my analogue active crossover quite a bit as the bass content has got louder/deeper.

I don't know if there will be any further changes, but the whole set up is sounding very good indeed. It's the best sound I have had in my room and I could quite easily live with it. My recent speakers, as a yard stick, have been Tannoy Cheviot/Cellestion 66/Yamaha NS1000M. I've got deeper bass and a cleaner top end than any of them, voices are particular natural and low in sibilance. The mid range could possibly lose out to the Yamaha's and Cellestions. The Yamaha's are cleaner and more transparent and dynamic, but not as rich or warm (small differences). The strong mids on the Cellestions are richer if slightly more grain to them, maybe a touch more slam in the upper bass.

I have lots more experimenting to do, including going with digital crossovers and trying different mid ranges, but this is a reference point, one I may come back to if things don't pan out, because it does work for me. Really enjoyed a live Radio session from the Cheltenham Jazz festival the other night.

[Qwin]

SUMMARY AND CONCLUSIONS

So, I have tried the passive Quad Mid/Tweeter set up, paired with both the Yamaha 12" Bass and Scanspeak 12" Bass, crossed actively at 310Hz.
Each configuration had 150 hrs use before evaluation and were auditioned in my living room and in a larger setting.
The Yamaha version was used at the 2017 Hifi WigWam Scalford Show and the Scanspeak at the NEBO 8 bake off.

My concerns about the Scanspeaks ability to perform in the upper bass and crossover region were unfounded and it out performed the Yamaha in every area. Obviously from the specification, it would have deeper bass, but its noticeably a lot deeper, which gives a strong platform to work with. Its faster and tighter, not that the Yamaha is poor in these areas, but the Scanspeak is better and can only improve in a more rigid cabinet. The big surprise was in its upper region, where it is subtle and tuneful, blending seamlessly with the mid range. Comparatively the Yamaha is muddy and slow, not that I would ever have said that prior to the comparison, as I like the Yamaha's a lot.

The overall presentation of the speaker system using the Scanspeak is very enjoyable, it has depth and detail. The Ribbon Tweeter is very clean, not spitty like some and produces sweet highs. The mid range is musical and vocals are particularly well produced. It's by no means a tame sound and rock guitar riffs soar. London Grammars “Hey Now” has a deep droning bass note that typically sets rooms off, with this set up it has a cleaner more controlled sound with layering and depth in the note I wasn't aware of previously and my room doesn't complain in quite the same way because of it.

This combination of a pair of book shelf speakers, mated with a pair of sealed woofers instead of the usual single Sub Woofer, is something I had to try. The results in both my small, less than ideal room and in a much larger setting are very pleasing and its a sound I could easily live with. This is a milestone and a reference point, should I want to revisit and continue the development from here, maybe fully active?

I am now curious about how the Scanspeak 12” Bass and Fountek Ribbon Tweeter will work with the legendary Yamaha Beryllium Dome Midrange. This will be a fully active set up, call it NS-1000 revisited!
But that's another project.

[Firebottle]

Brilliant result Ken :D

[danilo]

Well I have 100hrs on them as a pair.

I wasn't really sure about running in drivers, as having much effect, I know there are firm believers/disbelievers, both from the user and manufacturing front.

Previously, when running in smaller drivers, I noticed a very small change early on and on a complete speaker, I noticed later changes, that could be put down to cross over burn in as much as anything.



Interesting that;
Small belief in driver 'burn in' yet some in Crossover burn in.
You've got that notion reversed IMO.
Drivers do require their spiders to be flexed into subservience. Real and documented, repeatedly actually.
Electronics burn in is IMO a Faith based notion, with little to no evidence... spare me :-)

Other small point; Initial 'genuine' impression windows on New gear are in the one digit minutes.
Some claim only 1 to 2 mins, dunno. Only aware that it is a surprisingly short time span.
Our brains almost instantly Adapt to the new. Physiology/mother nature has clear dominion, whether we acknowledge it or not.
It's The Achille's Heel in Audio Weenie land. Where only instrumentations give replicable result.
Which really complicates the Hell out of DIY adventures sans capable analysis gear/protocols.
Just saying. I've been ass bit by all this before, causing me to run circles for a couple of years or so.
Wasn't that much Fun TBH.

[Macca]

Physiology has dominion

If that isn't an obscure prog rock album title then it damn well ought to be

[Qwin]

Interesting that;
Small belief in driver 'burn in' yet some in Crossover burn in.
You've got that notion reversed IMO.
Drivers do require their spiders to be flexed into subservience. Real and documented, repeatedly actually.
Electronics burn in is IMO a Faith based notion, with little to no evidence... spare me :-)

Other small point; Initial 'genuine' impression windows on New gear are in the one digit minutes.
Some claim only 1 to 2 mins, dunno. Only aware that it is a surprisingly short time span.
Our brains almost instantly Adapt to the new. Physiology/mother nature has clear dominion, whether we acknowledge it or not.
It's The Achille's Heel in Audio Weenie land. Where only instrumentations give replicable result.
Which really complicates the Hell out of DIY adventures sans capable analysis gear/protocols.
Just saying. I've been ass bit by all this before, causing me to run circles for a couple of years or so.
Wasn't that much Fun TBH.

Well Danilo you have highlighted controversial subjects that have been done to death, here and elsewhere, I wont get drawn as it will take over the thread.
I do what I do, based on what I hear, though measurements are steadily creeping in, as an aid. I make many mistakes along the way, but treat that as part of the learning process and my ears tell me if it's wrong.
I am not afraid to let my peers judge the results and confirm or shoot down what I have done, this set up was well received at the NEBO 8 meeting, so I must be getting some of it right. :D