Semi Active Three Way Speaker Project

[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

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]

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/showt...cD-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.

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

[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