about to build this - whad`ya reckon?

SpeakerBob

Member
2002-08-15 6:21 pm
UK
Hello all,

I've been browsing and reading for about 3 months on speakers and have decided on this - I reckon its a good combo, but have I missed anything? - I've saved up enough to build the bottom bass units (both sides), or the mid/tweet units......for a start..:) ...

3 way active using ESP boards, x-overed at 300Hz and 1500Hz (24Db/octave linkwitz riley)

(per speaker)
bass : 2x scan speak 25W 8565-01
mid :1x focal 6wm
hi: 1xscanspeak d29005/9900 revelator

would I be better with the seas excel tweeter (millenium)T25CF-002?

the bass cab is 120 litres sealed, with the mid/hi's above, time aligned in their own (seperate) enclosures with no baffles as such (bit like b+w`s round mid enclosures) 7 litres for mid, n/a for tweeters.

any input before I spend a fair bit on drivers would be cool - even if its just a yeah- i reckon it`ll be nice but check this out first type thing....

btw - it'll be similar to the andromeda on speakerbuiding.com if this helps you visualise.......

cheers in advance chaps,

Rob
 
Hi Rob,

though I cannot comment on the particular Focal, regarding the Scan-Speaks You choosed very well in my opinion!!

The Scan-Speaks 25W series I take for one of the best "woofers" avaible. The same apply for the Revelator - it is still among the best dome tweeters (but I have not heard the Seas millenium)!
You can hardly do any better with other drivers.

Even better that You decided for going active - that`s the way to go!

Also I like it that You`ll use a sealed enclosure and no bass-reflex.
Since You do it active anyway You might consider using a Linkwitz Transform Circuit . I have some experience using the LR-circuit with a Scan-25W and it works great - clean and deep bass (and the enclosure even do not need to be so big).
Defenitely worth a try in my opinion.

I`m sure this becomes a GREAT speaker!
All You still need are some good amps which can hold up in quality with Your fine drivers . Take a look at this threads
therefore:
http://209.151.66.66/forums/showthread.php?s=&threadid=890
http://209.151.66.66/forums/showthread.php?s=&threadid=5233
 

SpeakerBob

Member
2002-08-15 6:21 pm
UK
Hello Christoph - thanx for the reply...

This is pretty much the kind I was hoping for:)

About the linkwitz transform - according to winisd the twin sspeak drivers will go down to 36Hz(-3Db) so I'm pretty happy with that for now. However I do intend to make a surround pair and a sub to match as and when I can afford it! I know distortion is a factor when you boost lows so much, so if I went down the eq`d route I'd guess on using 4 x 12" drivers, each with its own amp to get the spl nice and clean........

I tried the links to the amps that you posted, but they did'nt work - I think the servers have just changed or something?

For the time being I am going to buy 3 x cyrus 1's as they`re very cheap at the moment, and I used to own a cyrus 2 and was pretty happy with that...............(I`ll be using my yamaha av amp as a pre until I get more money in the pot....)

A couple more answers like this and I'll order a few drive units!

btw - I can post pics of the speakers as they develop if anyones interested..... let me know.....


Cheers
Rob
 

SpeakerBob

Member
2002-08-15 6:21 pm
UK
Cheers Dan - had a look.....

I'd already caught the thread on the active xo`s, but will keep my eyes on it if it develops. I'm not sure about the amp thing as yet - I'll definitely start with the cyrus1's cos they're cheap.
I'm kind of drawn to ss for the bass and tubes for the mids and tweets, but that will be happening a long time from now!

I bought a book on building tube amps and I guess I've got a lot of time to read it over so I'll be ready to have a go at building a pair of tube amps. Just need the cash...


Anyone else want to give me the go-ahead? Just need a few more diy'ers to say "yep Rob I reckon that'll sound good" and I'll order the first 4 drivers..............

Rob
 

SpeakerBob

Member
2002-08-15 6:21 pm
UK
one other question for you all though...
the bass drivers are 8 ohm units and I was going to wire them parallel and drive them as a 4 ohm load - would I improve things if I used a stereo amp for each bass enclosure , driving 1 speaker per channel at 8 ohms? Does it depend more on the choice of amp?

Cheers
Rob
 
About the Cyrus amps...

Just wanted to comment on the cyrus1 & 2 amps.

I've been a fan of Cyrus amplification when i started out this hobby and only recently upgraded to a 85wpc Sonogy catana amp as the Cyrus 2 (despite modifications) cannot drive my speakers (Dynaudio Contour 1.3SE) well. By the way, resolution on my system improved with the Sonogy too but the modded Cyrus 2 did something really magical to vocals.

The cyrus amps can be improved by upgrading the diodes, main ps caps as well as signal path caps. The PS caps are hard to miss, 2 large Elna CE-Ws underneath the volume pot. Signal path caps are the 4 50v 220uf caps beside each transistor (Cyrus 2 has 4, Cyrus 1 only has 2)

The optional power supply, PSX, for Cyrus amps is almost a must. That too can be upgraded further so that YOU DONT NEED TO POWER UP THE CYRUS AMP, ONLY THE PSX.

I can only reccomend using Cyrus amps to drive the vocal range as after modifications they really do shine there. The bass is only slightly lower than 40hz and very muffled if i remember but its all judged by ear only. Since you are activing amplifiying them, they might perform better doing the lows but i doubt it'll be by a far mile.

By the way, the later range of Cyrus (3, 5 & 7) are less musical and prone to failure as i discovered corresponding with a few dejected owners. Having opened up the 1, 2 and 5, i can safely reccomend only the 2 & straightline. Rest are not worth your time.

Chris
 

SpeakerBob

Member
2002-08-15 6:21 pm
UK
Thankyou for the info on the Cyrus amps, Chris

I've got to say I was pretty upset when my cyrus2/psx died on me. I should have got it repaired (for the second time) -but I decided on an av amp instead - the lure of DD5.1:)

However, I soon got miffed at listening to music on this system hence the speaker project, and the amp upgrades too...

Thanks for the congrats Charles
it looks like you guys are into the sealed boxes! - I had vented twin subs in my car, and then tried a pair of sealed. I still have the sealed ones in my boot.
My car system is active 2-way. It was my car setup and when I added a subwoofer at home that made me want to go active 3 way. (x-over at 90Hz cleaned up the mid/treble on my b+w 602`s enough for me to take notice!)

Thankyou all once more for your input guys!

Rob
 
The four caps close to the output transistors are the power supply bypass caps and are not in the signal path - don't you know how an amp works before you are going to modify it ?
There is a small bipolar electrolytic cap at the input of the amp (4.7yF as far as I remember). This one can easily be changed with a suitable foil type. But be sure to use good one.

The last Cyrus2 with four (small) transistors was made back in the eighties, that is why all the caps in your amps needed an upgrade anyway - the buffer caps might have been dry already. The Cyrus range from this time was prone to dry caps, do change the psu caps of the preamp too (if you use it).

Klaus
 

SpeakerBob

Member
2002-08-15 6:21 pm
UK
thanx for the input, Klaus - I dont think I'm ready to take the amps apart yet as I'm concentrating on getting the speakers built first;)

I've just ordered the focal mids - they'll be here friday so I can start on the mid/tweet enclosure next week.
I'm about to order the tweeters and 1 of the bass units - I'll order the other 3 after I have sold on my current speakers and built the x-over .(and of course bought the 3 cyrus amps!)

Also yet to order the mdf to start the cabs, but it will all come together in the end (I hope:D )

As I said I'll keep some photos from the build, and start hassling you guys when the x-overs dont work etc etc.......

Cheers

Rob
 
I'm about to order the tweeters and 1 of the bass units - I'll order the other 3 after I have sold on my current speakers and built the x-over .(and of course bought the 3 cyrus amps!)
Rob:
It might be a not so good idea to order one woofer now and the other 3 later.
IMO it`s always better to order drivers from the same type for one project in one hit. Though Scan-Speak without doubt is of the better (best) brands also what concerns serial continuity of specs, buying all the drivers at once more likely insures that they are from the same manufaction lot and hence more likely they will be completly identical.
I wouldn´t risk eventually to have one of the woofers even slightly (more or less) different from the others.
When placing Your order You may even ask for getting units of continuous serial numbers if possible.

Just my 2 cents
 

SpeakerBob

Member
2002-08-15 6:21 pm
UK
Too late :( Its already been ordered.....

I kind of went along with your thinking - thats why I ordered a pair of tweets and a pair of mids. I really need the woofer to be able to measure up properly for the cabinet, and I cant afford to buy all 4 now! I will e-mail the shop now and see if they'll put aside 3 from the same batch for me to buy a soon as I can....

Of all the drivers I decided the bass ones would be less noticable if there was a variation in them, also as i'm using 2 per speaker it would notice even less - hopefully!

Thanks for your continuing to monitor this thread:) its appreciated..

Cheers

Rob
 
lohk said:
The four caps close to the output transistors are the power supply bypass caps and are not in the signal path - don't you know how an amp works before you are going to modify it ?

Klaus

Actually i didn't then... not now too. Was reccomended to change some caps in amps to audiograde ones and did so. Thanks for the correction... I believe i had changed both these 4 caps as well as the PS ones together so did not notice the lack of a change in sound.
 

SpeakerBob

Member
2002-08-15 6:21 pm
UK
Good news on the bass drivers:D

the distributer says they come in pairs, so I have ordered 2 drivers instead, and they've said they'll put the next 2 aside for me 'til I get my next months pay in.......

Ordering the mdf next Thursday - 2 sheets of 38mm, 1 x 18mm:)

can't wait

Rob.......