'Perceive v2.0' Construction Diary

ShinOBIWAN

diyAudio Member
2004-02-25 9:13 pm
UK
Hello all

To save re-iterating actually what's going on here take a look at this thread:

Perceive v1.0 Thread

In it you'll find details of the Perceive v1.0 such as drivers, construction, lots of questions/answers on virtually all aspects of design such as box construction, drivers etc. There is also an interesting discussion on the merits and implemention details of a full digital active XO with digital room correction (DRC) using a dedicated PC and software that provides quite startling quality.

During this time the v1.0 took some shifts and turns throughout the few months I'd spent building, testing and tweaking and compared to the original plan the following had changed:
  • I'd changed the analogue active XO to full digital and saw a big improvement especially with DRC/EQ.
  • The loading of the bass cabinet was changed from sealed to ported to help cure a very slightly muffled lower midrange/upper bass and to create a much better transition to the ATC midrange.
  • The 6 amps that are used to tri-amp the speaker switched from Rod Elliots ESP P101 to Krell Clone and then to AKSA 55 & 100.
  • Swapped the ATC SM75-150 for the SM75-150S 'Super' version, I got a pretty good deal here and only paid £100 for this swap :)
  • And then lastly, I switched out the Seas 4 x L22's used for the lowpass to 2 x Seas Excel W22's for an incremental upgrade in sound quality.

With all these changes it simply felt like a fudge and that a complete rebuild was in order to take stock of the tweaks and modifications, especially the lowpass driver change.

As it stands now I'm using the following drivers:

  • Scanspeak R2904 Ring Radiator Tweeter
  • ATC SM75-150S 3" Dome Midrange
  • Seas W22EX001 8" Bass

I'll post some specifics on amplification and XO details later on the thread.

Scale drawing of the v2.0:

[IMGDEAD]http://img.villagephotos.com/p/2005-7/1050288/laminar3.jpg[/IMGDEAD]

Not really done a great deal as I've been modelling enclosures for the W22 and looking at existing designs using this driver to see what other designers thought. Got that sorted though and I started a couple of days ago on cutting.

Here's the results so far:

[IMGDEAD]http://img.villagephotos.com/p/2005-7/1050288/bassmik2.JPG[/IMGDEAD]

Lots more to do obviously but my aim is to have these finished by Christmas ready for the holidays :)

More to come over the next few weeks.

Cheers,
Ant
 
I want it ! and thanks

ShinOBIWAN,

Firstly, as a newcomer to this forum and DIY I would like to thank you for all your informative contributions to many threads I have read, especially on active crossover/PC based DRC etc.

Secondly, this looks like a great project, and I can't wait to hear about the results. I'm already thinking I will want to recreate it.

Thanks Jack
 

ShinOBIWAN

diyAudio Member
2004-02-25 9:13 pm
UK
Re: I want it ! and thanks

Vil said:
Shin ,

looks like another nice tread just came to life , but I am curious - you decided not go for Supravox at bass position ,what reasons ?

Hey Vil!

Your XO suggestions have been invaluable to me so its good to see you here again :)

Regarding the Supravox, I had something of a nightmare getting hold of two, eventually I tracked down Clofis in the Netherlands but they won't ship to the UK without CC payment. I then found out that Supravox France sells direct to the puplic but got a quite amazing quote of 650Euro's including taxes for two drivers shipped to the UK .
Can't afford that considering that I'm going to definitely need to build a sub to augment the last couple of octaves, doubley so with the supravox actually since its around -10db at 50hz. By the time I'd factored this in I was looking at another £400 for the sub driver and £250 for a decent plate amp. It was all starting to look like very diminishing returns on what was nearly double the price for the Supravox's over the W22's. I guess you've got to draw the line somewhere regardless of any design ideal's such as 'reference'.

No doubt the Supravox's are better drivers but by how much? Well I'd guess at not a lot. But if these W22's don't work out I'll rebuild the entire thing again for the 3rd time ;) :D

jacklelad said:
ShinOBIWAN,

Firstly, as a newcomer to this forum and DIY I would like to thank you for all your informative contributions to many threads I have read, especially on active crossover/PC based DRC etc.

Secondly, this looks like a great project, and I can't wait to hear about the results. I'm already thinking I will want to recreate it.

Thanks Jack

Thanks for that Jack, appreciate it.
 

ShinOBIWAN

diyAudio Member
2004-02-25 9:13 pm
UK
A CAD rendering of the finished speaker to give you an idea of look:

Graphic1.jpg
 
Nice man-

One day I'll make my speaks so pretty. Right now I just got this Pro Tools HD rig that I'm learning how to use and I got my XO setup in PT with no latency and an easy switch to FIR xo's. Plus the digi 192 DA's are sounding killer compared to the motu crap I was using-

Anyway looks like they just keep gettin better! I wish I could hear them. . .
 

ShinOBIWAN

diyAudio Member
2004-02-25 9:13 pm
UK
m0tion said:
I've just got this feeling that when these things are done you could charge admission to hear them.

:D

I really hope that is true, I could then recoupe some of the money I've lost/wasted through swapping bits.

RyanC said:
Nice man-

One day I'll make my speaks so pretty. Right now I just got this Pro Tools HD rig that I'm learning how to use and I got my XO setup in PT with no latency and an easy switch to FIR xo's. Plus the digi 192 DA's are sounding killer compared to the motu crap I was using-

Anyway looks like they just keep gettin better! I wish I could hear them. . .

Hi again Ryan,

Still messing with the XO? Its addictive isn't it :)

I had 3 presets that all sounded great but couldn't decide which sounded best over a wide genre of music. One was great for dance, another for acoustic/classical and the last favoured bass heavy material such as home theater.
Its just a hell of a lot of fun having all that flexibility, its quite feasible to create an entire crossover within a day but I find its best to keep coming back over a period of a couple of weels to really listen and appreciate the subtle changes that can make the difference.
 
Ahh yes-

I'm going with 2 main ones right now. One is a 96dB/oct using the UA cambridge EQ on the elliptic 6 filter. This one is not native (TDM or UAD card only) so unfoutunatly you all can't play with it cheaply. The other is the FIR filters with the waves lineq pack. I do know what you mean by different ones being better- like for Rock or Hip hop I like my big ol TC2+'s comin up to 200hz even. But for jazz it just sounds bad! Funny that you can tune it pretty flat either way and it sounds so different. Also it is amazing how diffent the lowest octive is mixed on different records.

Man Protools HD sounds good- i think it has somthing to do with the fact that all clocking is done at 256 x fs, also that the WC cable is integrated with the digital cable so the length is identical.

What is really cool is that a single fader can control levels for as many outs as you want (via grouping or multi-channel tracks) so I could easily have an all active realtime XO for a full surround system! It would probably eat up a whole HD card though.

Too bad this stuff is so spendy- I bet ProTools would make another marked improvement, and it certenly has lower latency than VST.

On an interesting note- using the FIR setup makes me not want to use IIR filters in mixing- then it occured to me- Pretty much everything you hear has gone through lots of IIR filters (even just HPF's on mic preamps). I notice on a drum set that you loose punch when you engage 2 self canceling IIR filters (eg one is +3dB at 1k one is -3dB at 1k Q is the same). Too bad mixing is not really feasable with FIR filters yet.

How often do you find yourself going damn thousands of dollars (or pounds for you) and I'm still no where near "perfect". I guess we are all going to have to settle for the pursuit of perfection. . .

RC
 

Vil

Member
2003-01-08 10:15 am
Europe
>>>Man Protools HD sounds good- i think it has somthing to do with the fact that all clocking is done at 256 x fs, also that the WC cable is integrated with the digital cable so the length is identical.


do you remember my post in #1 tread ?
low jitter clock source is at the top of most important things for DAC/ADC . 256F (super clock) means no PLL's at conversion clocking parth .

V.
 

ShinOBIWAN

diyAudio Member
2004-02-25 9:13 pm
UK
tktran said:
Hello,

Did I read correctly in your first post that you intend to swap 4 x L22RNX/P for 2 x W22EX001?

What was the aim of this change?

regards.

Hi TK,

The change reflects the choice to suplement the output below 40hz for music and 80hz for HT. I'm going to mess around with a high pass on the W22's to help reduce the work load and keep the low stuff in the more capable hands of the sub for home theater for sure though with music I'll have to experiment I suspect.

The 4 x L22's just couldn't output clean bass down to 20hz well. Play something like the THX lightening intro from the new Starwars movies and they bottom out quite easily at just a modest volume level.

The W22 is a 'better' driver as a whole also.

Another thing was a question of amplification, I'm saving myself the hassle of needing 2 amps or 1 large amp on the bass section by going with just a single driver for the bass rather than two. This is a bonus really and a secondary consideration to the above points.

Care to share your thoughts on the change?
 
ShinOBIWAN said:


Hi TK,

The change reflects the choice to suplement the output below 40hz for music and 80hz for HT. I'm going to mess around with a high pass on the W22's to help reduce the work load and keep the low stuff in the more capable hands of the sub for home theater for sure though with music I'll have to experiment I suspect.

The 4 x L22's just couldn't output clean bass down to 20hz well. Play something like the THX lightening intro from the new Starwars movies and they bottom out quite easily at just a modest volume level.

The W22 is a 'better' driver as a whole also.

Another thing was a question of amplification, I'm saving myself the hassle of needing 2 amps or 1 large amp on the bass section by going with just a single driver for the bass rather than two. This is a bonus really and a secondary consideration to the above points.

Care to share your thoughts on the change?


I'm curious if you were deviating from the real perceive... why you didn't go with better drivers than the Seas

however great start they look lovely... if only they sound as good as they look ;)
 

tktran

Disabled Account
2003-03-17 4:30 am
Perth
kram0.com
Hi Shin,

Ok I understand now. You are changing from 4 x L22RNX4P to 2 x W22EX001 + subwoofer

I think that's a good idea. Music may be ok, but for home theatre the W22EX001 would benefit from assistance below 100Hz. For real HT entertainment we could all do with large high excursion woofers :D .

Linkwitz supplements with 2x W22EX01 with a quad of 10" XLS woofers in his Orion, for music. Then for home theatre he calls for additional 12" monopole subwoofer(s).

Let's make it clear that without a subwoofer, in the bass department, 2 x W22EX001 will not be better than 4 x L22RNX4P. The quad of L22RNX4P have higher volume displacement by a factor of 2.8 times, as well as a slight sensitivity advantage. This means both lower non-linear distortion levels and greater SPL in the bass.

W22EX001 distortion attached:
 

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ShinOBIWAN

diyAudio Member
2004-02-25 9:13 pm
UK
Hi again TK

I think that's a good idea. Music may be ok, but for home theatre the W22EX001 would benefit from assistance below 100Hz. For real HT entertainment we could all do with large high excursion woofers :D .

I'll be using subs with music too, without I'd expect that dynamics would be limited and too much pressure would be on that single 8". Best to use stereo subs and keep the rest of the range focused on low distortion.

Let's make it clear that without a subwoofer, in the bass department, 2 x W22EX001 will not be better than 4 x L22RNX4P. The quad of L22RNX4P have higher volume displacement by a factor of 2.8 times, as well as a slight sensitivity advantage. This means both lower non-linear distortion levels and greater SPL in the bass.

There's absolutely no question about the subs being included, I've redesigned the whole thing around the need for more bass, lower distortion and extra lower mid range clarity. The W22 will be more than enough from 80hz up to the cross to the ATC.
I'd agree that without the sub things would look pretty poor bass wise though. Afterall 2 x 8" were weak and still unsuitable for HT, so subs would have been mandatory with those too.

The effort I've gone to this time around with regards to a clean lower mid range & bass is quite extensive:

The cabinet which houses the Excel bass driver has 18mm + 9mm MDF walls and the top and bottom walls are 36mm thick. Also rather than using large panels I've subdivided the largest sections to keep panel size down in order to minimise resonances. Along with this there's also some of the most extensive bracing I've done.

Another considered effort was that there are no parallel walls to keep standing waves to a minimum.

I've also double up on dedshete panels and have fitted an Auralex 4" Wedge directly on the wall behind the driver to absorb and difuse some of the back wave. The baffle for the W22 is also 3" thick with a magnet brace .

This kind of construction requires a fair amount of effort but the results speak for themselves - the knuckle test on a nearly finished cabinet shows them to be very sturdy with virtually no resonances. This is clearly a very good foundation to hear the best from the W22 without colouration, the next step would have to be something like aluminium, concrete etc.

W22EX001 distortion attached: [/B]

Thanks for that, the THD numbers from 80hz to 400hz(the range I plan to use) look excellent. They are less than 1% at 80hz and around 0.1% - 0.3% throughout the rest of the range. Those are enviable THD figures by anyones standards.
 

ShinOBIWAN

diyAudio Member
2004-02-25 9:13 pm
UK
Audiophilenoob said:



I'm curious if you were deviating from the real perceive... why you didn't go with better drivers than the Seas

however great start they look lovely... if only they sound as good as they look ;)

Well if they sound 5% better than the last ones did at the end of the changes then I only wish I'd been more extravagant on the cabinets since they won't do the sound justice.

The effort gone into these speakers with all the additions and revisions is almost like a commercial R&D phase. Each change brings even more improvements and if you'd heard the originals before I switched cabinets, loading, mid range, bass drivers, and analogue active XO's you'll quickly realise that these are going to be among the best 3-ways you'll likely hear.

I'm proud of what I create so please, next time, keep it in your pants.

Also...

ATC vs. PHL 1120? No contest! :D ;)

PS. I'll be selling these an ebay under the false pretence that these were designed by ex B&W Nautilus project employee's, the reserve will be set at £10000 for anyone who's interested. ;)
 

tktran

Disabled Account
2003-03-17 4:30 am
Perth
kram0.com
"The baffle for the W22 is also 3" thick with a magnet brace"

That's overkill... or at least killing your chamfer bit. :clown:

AFAIK the W22EX001 IS the lowest distortion driver between 150 and 1.5K Hz, and should make a excellent upper bass and low midrange driver in a 4 way or 3 way + subwoofers.

Look forward to seeing your pics. I envy your cabinet building skills.
 

ShinOBIWAN

diyAudio Member
2004-02-25 9:13 pm
UK
tktran said:
That's overkill... or at least killing your chamfer bit. :clown:


Possibly but overkill never hurt anyone. The last cabinet has 3" baffle for the mid and treble but the baffle on the bass cabinet was only 1" thick. This time I thought it best to match the two.

Look forward to seeing your pics. I envy your cabinet building skills.

Thanks TK, I'll get some more pictures up soon.
 
ShinOBIWAN said:


Well if they sound 5% better than the last ones did at the end of the changes then I only wish I'd been more extravagant on the cabinets since they won't do the sound justice.

The effort gone into these speakers with all the additions and revisions is almost like a commercial R&D phase. Each change brings even more improvements and if you'd heard the originals before I switched cabinets, loading, mid range, bass drivers, and analogue active XO's you'll quickly realise that these are going to be among the best 3-ways you'll likely hear.

I'm proud of what I create so please, next time, keep it in your pants.

Also...

ATC vs. PHL 1120? No contest! :D ;)

PS. I'll be selling these an ebay under the false pretence that these were designed by ex B&W Nautilus project employee's, the reserve will be set at £10000 for anyone who's interested. ;)

I guess I should keep out of your threads because you can't take a compliment without resorting to childish games :rolleyes:

oh and BTW... the PHL owns the ATC... I'm surprised you didn't know this... ;) well it certainly owns it in SPL... also I wouldn't be surprised in SQ either ;)


you should be proud... they look like they're going to be fanatastic... I was just curious why you switched to seas... not that I doubt they'll be superior to the orginial speakers