Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Multi-Way Conventional loudspeakers with crossovers

Sanity check for a 'newbie' Heybrook Sextet ribbon tweeter replacement
Sanity check for a 'newbie' Heybrook Sextet ribbon tweeter replacement
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 Search this Thread
Old 12th June 2018, 06:51 PM   #1
damiangt3 is offline damiangt3  United Kingdom
diyAudio Member
 
Join Date: Feb 2014
Default Sanity check for a 'newbie' Heybrook Sextet ribbon tweeter replacement

Hello,

I've got an aged pair of Heybrook Sextets and as a result of an incident with a cat's claw and a Tonegen (Infinity EMIT-K) ribbon tweeter, coupled with age I now find myself with substituting these units for something more modern.

In keeping with the ribbon theme I've gone for the well respected Fountek NeoCD1.0, firstly I simply replaced the tweeter leaving the crossover intact to see where to start, let's just say it was a little bright! Doing a frequency sweep and comparing to the working Tonegen I was staggered at the range the Fountek had, it was going all the way down past 600hz when I decided to stop, the Tonegen had rolled off at around 1600-1800hz.

So keeping the Peter Comeau's 1st order intact I decided to replace the 2.2uf capacitor with a 4.7uf (Mundorf MCap Oil), this improved the roll-off but it still a little caused me a little concern. I then made the decision to use a 2nd order LR (3.3uf and 0.33mH) which worked well, rolling off better and providing some more protection.

The Fountek was still bright, however it and the replacement caps in the crossover are new so I decided to leave it a few hours to bed in and 'calm down' a bit, which it did, in the last day or so I started into introduce a 3.3ohm resistor before the cap which has helped and to be honest is sounding quite wonderful for a early install, pre-full bedding in.

I've left the woofer and mid alone, they are the standard Seas units. The resistor and caps in the crossover have been replaced with same value items, albeit with the entire crossover now mounted externally.

Could someone tell me if the values I've used in the HF crossover and the placement of the attenuating resistor are good to go and my ears aren't deceiving me.

Many thanks!
  Reply With Quote
Old 12th June 2018, 07:59 PM   #2
system7 is offline system7  United Kingdom
diyAudio Member
 
system7's Avatar
 
Join Date: Aug 2008
Location: Portsmouth UK
I can't imagine anything in a capacitor "beds down" unless the electrons are getting sleepy... really!

Homework:
www.audioexcite.com >> Fountek NeoCD1.0
Speedster - undefinition
NeoCD1.0

Fragile, isn't it? 3.5kHz third order recommended. 3.3uF and 0.33mH is your standard 8 ohm 3kHz second order. Maybe 4.7uF and 0.2mH is better for 5 ohms. And 3.3R in front of that ought to pad it down about 3dB.

So, you are on the right track here. I don't suppose the overall setup will end up much different from this for a 6" plus 5" plus 3.5kHz tweeter:
SEAS-3-Way-Classic
__________________
Best Regards from Steve in Portsmouth, UK.
  Reply With Quote
Old 12th June 2018, 08:04 PM   #3
damiangt3 is offline damiangt3  United Kingdom
diyAudio Member
 
Join Date: Feb 2014
Quote:
Originally Posted by system7 View Post
I can't imagine anything in a capacitor "beds down" unless the electrons are getting sleepy... really!

Homework:
www.audioexcite.com >> Fountek NeoCD1.0
Speedster - undefinition
NeoCD1.0

Fragile, isn't it? 3.5kHz third order recommended. 3.3uF and 0.33mH is your standard 8 ohm 3kHz second order. Maybe 4.7uF and 0.2mH is better for 5 ohms. And 3.3R in front of that ought to pad it down about 3dB.

So, you are on the right track here. I don't suppose the overall setup will end up much different from this for a 6" plus 5" plus 3.5kHz tweeter:
SEAS-3-Way-Classic
LOL, I know what you mean.

Thanks for those links, really appreciate it.
  Reply With Quote
Old 12th June 2018, 08:11 PM   #4
system7 is offline system7  United Kingdom
diyAudio Member
 
system7's Avatar
 
Join Date: Aug 2008
Location: Portsmouth UK
I think you can pretty much treat it like any old 5-6 ohm 90dB tweeter on a third order 3-3.5kHz crossover. Resistor adjust in front of network.

Many ways to skin a cat.

3.9R/3.3uF/0.2mH/10uF (KEF)
3.9R/4uF/0.2mH/4uF (KEF)
3.9R/4uF/0.2mH/6uF (Celestion)

With a second order, you shouldn't drive it too loud. How it works.
__________________
Best Regards from Steve in Portsmouth, UK.
  Reply With Quote
Old 12th June 2018, 08:22 PM   #5
damiangt3 is offline damiangt3  United Kingdom
diyAudio Member
 
Join Date: Feb 2014
Quote:
Originally Posted by system7 View Post
I think you can pretty much treat it like any old 5-6 ohm 90dB tweeter on a third order 3-3.5kHz crossover. Resistor adjust in front of network.

Many ways to skin a cat.

3.9R/3.3uF/0.2mH/10uF (KEF)
3.9R/4uF/0.2mH/4uF (KEF)
3.9R/4uF/0.2mH/6uF (Celestion)

With a second order, you shouldn't drive it too loud. How it works.
Thanks again, I'll have have to do some homework on 3rd order crossovers.

That Speedster link is tempting....and I don't need another set of speakers!
  Reply With Quote
Old 12th June 2018, 08:35 PM   #6
system7 is offline system7  United Kingdom
diyAudio Member
 
system7's Avatar
 
Join Date: Aug 2008
Location: Portsmouth UK
Ideally you model these things.

Using your existing values, this comes out at 3kHz crossover. Red is adjustment.

It rises 3dB towards the top end, but not bad. Really you do need a 0.2mH here. Or unwind the coil.
Attached Images
File Type: png 3kHz Crossover.PNG (3.5 KB, 75 views)
__________________
Best Regards from Steve in Portsmouth, UK.
  Reply With Quote
Old 13th June 2018, 08:27 AM   #7
damiangt3 is offline damiangt3  United Kingdom
diyAudio Member
 
Join Date: Feb 2014
Steve, what software do you use to juggle the component values?
  Reply With Quote
Old 13th June 2018, 05:26 PM   #8
system7 is offline system7  United Kingdom
diyAudio Member
 
system7's Avatar
 
Join Date: Aug 2008
Location: Portsmouth UK
I use Visaton Boxsim. Software | Visaton

It's quite easy to set up a box, choose some similar drivers and place them on the baffle. Then do a crossover and optimise it.

You can even shortcut by importing a projekte into the bpj folder that does most of what you want and modify it:
3 Wege – Boxsim Projektdatenbank

I found that about 6.2R/3.3uf/0.2mH/10uF does the right things for you. 6.2R/4.7uF/0.2mH/4.7uF (dotted) has worse impedance although it is flatter. The 15R is just a modelling device to get the tweeter to 5 ohms and is not fitted.
Attached Images
File Type: png Ribbon tweeter circuit.PNG (12.0 KB, 48 views)
File Type: png Ribbon Tweeter FR.PNG (22.4 KB, 45 views)
__________________
Best Regards from Steve in Portsmouth, UK.
  Reply With Quote
Old 13th June 2018, 08:01 PM   #9
chris661 is offline chris661  United Kingdom
diyAudio Member
 
chris661's Avatar
 
Join Date: Feb 2008
Location: Sheffield
... Or you could use XSim, measure your drivers and do it properly.

Steve, I get that you find the results acceptable, but randomly substituting drivers into a simulation program is not the way to get accurate results.

Damian, larger capacitor values means the ribbon is playing lower down the frequency range. I'd put the cap back to how you found it, and then add a resistor or L-pad to attenuate the new ribbon.

Chris
  Reply With Quote
Old 14th June 2018, 07:53 AM   #10
damiangt3 is offline damiangt3  United Kingdom
diyAudio Member
 
Join Date: Feb 2014
Thanks guys, time to start playing again. How do you put the worms back in the can?
  Reply With Quote

Reply


Sanity check for a 'newbie' Heybrook Sextet ribbon tweeter replacementHide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

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
3-way sanity check Mayuri Multi-Way 9 29th August 2017 12:05 PM
2-Way Sanity Check wrenchone Multi-Way 8 9th December 2011 07:54 PM
Sanity Check ..... please Lostcause Digital Source 0 16th October 2008 06:19 PM
Sanity Check- Fix fostex high end rolloff without tweeter? GratefulTony Full Range 10 9th July 2008 08:44 PM
XO sanity check for newbie avizandum Multi-Way 2 30th December 2007 08:29 PM


New To Site? Need Help?

All times are GMT. The time now is 11:06 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio
Wiki