Go Back   Home > Forums > >

Multi-Way Conventional loudspeakers with crossovers

Seas Loki crossover
Seas Loki crossover
Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools
Old 21st March 2007, 04:04 PM   #1
spendorspain is offline spendorspain  Spain
diyAudio Member
 
Join Date: Apr 2005
Location: Spain
Default Seas Loki crossover

Hi,

Im building the Madisound Loki loudspeaker kit, based in the SEAS H1333 6in. coaxial driver with a two-way crossover (also designed by SEAS) made with Bennic/Solen poly caps and Sidewinder air core inductors, sold already mounted in a pcb by Madisound. Because I need to place it very close to the rear wall, Ive discarded the original reflex design in favour of a sealed-box of about 7.5 liters of internal volume and a Qtc of 0.74. Ill use it as surround loudspeaker in my music/cinema system and I hope the lean tonal balance (the WinISD predicted 6dB point is around 50Hz) will be compensated with the rear wall gain in the bass. The front baffle will be covered with a 5mm non-varnished cork sheet for flush-mounting the driver and reduce diffraction.

The kit is very easy to build, but I have a doubt regarding the crossover. The designer says that the 3.0uF cap in the treble section is optional and when used in parallel with the non-optional 2.5 ohm resistor it lifts the response above 10kHz slightly (see attached images). The tonal balance of my front loudspeakers (Spendor SP1/2E) is rather mellow and I very much prefer a non distracting, soft and subtle sound for rear channels. Id also like to avoid (if possible) a L-pad (more resistors) for attenuating the surround treble level. Do you think the removal of the 3.0uF cap will be enough for soften the surrounds? Is there any other modification for the crossover that I can try?

Thanks in advance

Regards
Jose
Attached Images
File Type: jpg treble section.jpg (18.5 KB, 891 views)
  Reply With Quote
Old 21st March 2007, 04:07 PM   #2
spendorspain is offline spendorspain  Spain
diyAudio Member
 
Join Date: Apr 2005
Location: Spain
and this is the bass section crossover schematic
Attached Images
File Type: jpg bass section.jpg (16.8 KB, 827 views)
  Reply With Quote
Old 21st March 2007, 05:05 PM   #3
Cal Weldon is offline Cal Weldon  Canada
Speakerholic
diyAudio Moderator
 
Cal Weldon's Avatar
 
Join Date: Jan 2004
Location: Near Vancouver
Seas Loki crossover
Sound is so subjective, it's difficult for us to answer that for you. I would suggest trying the removal first and if that is not enough, the next step is to reconsider padding the tweeter.
  Reply With Quote
Old 21st March 2007, 06:32 PM   #4
sreten is offline sreten  United Kingdom
R.I.P.
 
Join Date: Nov 2003
Location: Brighton UK
Hi, I would simply omit the capacitor, /sreten.
  Reply With Quote
Old 24th March 2007, 11:27 AM   #5
spendorspain is offline spendorspain  Spain
diyAudio Member
 
Join Date: Apr 2005
Location: Spain
Thank you for your comments. Audio quality is, of course, very subjetive (and perhaps more so with loudspeakers) and I know I prefer a laid-back and subtle sound rather than upfront and agressive. I'll desolder the 3.0uF cap (isolating the remaining leads) but leaving it in place, glued to the XO pcb.

Having read the posts here about cork baffle treatment, I'm also decided to use it for the front bafle finish.

Best regards
Jose
  Reply With Quote
Old 24th March 2007, 10:34 PM   #6
Ron E is offline Ron E  United States
diyAudio Member
 
Ron E's Avatar
 
Join Date: Jun 2002
Location: USA, MN
I heard these last tuesday, and they sound very nice. They sounded perhaps a bit "hotter" than the other speakers that day, but very transparent (no pun intended - the cone is transparent). Standing in front of one, about 1.5 meters away, the other speaker ~3 meters to my right was plainly audible. I wonder if removing the cap and increasing the resistor 0.5 to 1 ohm might not make them more to my liking. Hard to say without measuring and modeling.

Putting them in a smaller sealed box may change the baffle step and your set may sound somewhat different.
__________________
Our species needs, and deserves, a citizenry with minds wide awake and a basic understanding of how the world works. --Carl Sagan
Armaments, universal debt, and planned obsolescence--those are the three pillars of Western prosperity. Aldous Huxley
  Reply With Quote
Old 26th March 2007, 02:19 PM   #7
spendorspain is offline spendorspain  Spain
diyAudio Member
 
Join Date: Apr 2005
Location: Spain
Hi, Ron

I believe, for what I have read, that the Seas kits are very transparent and detailed but also perhaps a little bright, hence the thread Ive post here. If the rear loudspeakers call attention by themselves, the surround effect is less convincing and Id like to avoid this. In your post you said that increasing the series 2.5 ohm resistor to the tweeter 0.5 to 1 ohm can soften more the response. Is it as easy as fitting a 3, 3.5 or even 4 ohms 10w resistor in place of the original? Can be this done without modify the rest of the treble filter? If so, it would be ideal, as the high frequency response could be adjusted to my taste and loudspeaker placement without resorting to add another series resistor in a L-pad attenuator.

Also, it is true that the bass crossover is very simple, 2nd order with no baffle step compensation (which will need another inductor paralleled with a resistor in series with the woofer, I think), but I hope that the mounting on the rear wall will compensate this (btw, the front baffle width of my sealed box is 25 cm)

Regards
Jose
  Reply With Quote
Old 26th March 2007, 05:30 PM   #8
Ron E is offline Ron E  United States
diyAudio Member
 
Ron E's Avatar
 
Join Date: Jun 2002
Location: USA, MN
The woofer inductor is ~1.8mH, right? That is big enough to do some baffle step correction and correct for rising woofer response as well. You really should measure them before tweeking the crossover further. A small change in the series resistor shouldn't matter much, but model it (perhaps in Speaker Workshop) and see what it does.
__________________
Our species needs, and deserves, a citizenry with minds wide awake and a basic understanding of how the world works. --Carl Sagan
Armaments, universal debt, and planned obsolescence--those are the three pillars of Western prosperity. Aldous Huxley
  Reply to this post

Reply


Seas Loki crossoverHide this!Advertise here!
Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
crossover for seas 27TFFC zega55 Multi-Way 11 27th February 2007 06:26 PM
Crossover for Seas Excel TM? graks Multi-Way 4 20th September 2006 08:08 AM
Crossover question for Seas 27TFF DerrickM Multi-Way 5 29th October 2005 06:21 AM
Crossover for Seas 27TFFC & H1215 bigerik Multi-Way 3 14th December 2004 05:31 AM
Crossover Help for Seas Kits andrew Multi-Way 2 13th March 2004 03:34 AM


New To Site? Need Help?

All times are GMT. The time now is 09:33 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2021 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2021 DragonByte Technologies Ltd.
Copyright ©1999-2021 diyAudio
Wiki