Extended and Efficient midrange: what do we have here? - Page 2 - diyAudio
Go Back   Home > Forums > Loudspeakers > Multi-Way

Multi-Way Conventional loudspeakers with crossovers

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 29th November 2012, 04:14 PM   #11
zmyrna is offline zmyrna  United Kingdom
diyAudio Member
 
Join Date: Nov 2009
Location: London
On a slim OB, if single 8" starts rolling off at 400Hz, two 8" will start rolling of at 400Hz too. So what is the point?
If you want to cross lover, you either need a bigger baffle or active EQ.
MTM is hard to implement and expensive too.
If you pick a high eff mid, you can do with just one per channel.
In a closed box, single Supravox or PHL 6" should match fine with your tweeter.
  Reply With Quote
Old 29th November 2012, 04:29 PM   #12
Telstar is offline Telstar  Italy
diyAudio Member
 
Join Date: Dec 2007
Location: Italy
Quote:
Originally Posted by zmyrna View Post
On a slim OB, if single 8" starts rolling off at 400Hz, two 8" will start rolling of at 400Hz too.
Yes, but two drivers reinforce the emission in all their range, including <400hz, as they have a bit more baffle space, i suppose. I have more margin to play with mechanical filtering.
From my old sims, rolloff was around 350hz, so you are spot on with 400hz for a narrower baffle (25-30cm). But probably I wont go OB this time.

If you know higher efficiency mids, with a NON-rising FR please list them.
PHL maybe, but if i don't see at least the FR, I wont pick one, since they declare only 5-6khz as upper range, which translates in 3k max 1st order filter. PHL drivers do have one advantage, though: they exist in 16Ohm version.

Quote:
In a closed box, single Supravox or PHL 6" should match fine with your tweeter.
Probably yes, thanks
I have to study about baffle step and whether one or two drivers are better (to my ears).

I'll wait a few weeks for more suggestions.
__________________
"The total harmonic distortion is not a measure of the degree of distastefulness to the listener and it is recommended that its use should be discontinued." D. Masa, 1938
  Reply With Quote
Old 29th November 2012, 08:03 PM   #13
just another
diyAudio Moderator
 
wintermute's Avatar
 
Join Date: Aug 2003
Location: Sydney
Blog Entries: 22
when looking at the baffle step, plan for a 3-4db reduction in overall efficiency, so to reach your target of 95db efficiency you need 98-99db to start with for the drivers covering the baffle step region (ie your midbass drivers!) If you crossover at your baffle step frequency to your bass drivers you can then level match for the bass. To get a baffle step frequency of 200Hz you are going to need a wide baffle!

The other way to look at it is that all drivers must be 98-99db efficient and you do line level baffle step compensation. This though ups the ante for ALL of the drivers efficiency wise

Depending on the placement of the speakers you may need more or less baffle step compensation, but 3-4db is a good ballpark figure to plan on.

Tony.
__________________
Any intelligence I may appear to have is purely artificial!
Some of my photos
  Reply With Quote
Old 29th November 2012, 08:20 PM   #14
Jonasz is offline Jonasz  Sweden
diyAudio Member
 
Jonasz's Avatar
 
Join Date: Feb 2003
Location: Kristinehamn
B&W FST?

Should work fine down to about 300hz with a steep crossover.

Click the image to open in full size.
Click the image to open in full size.
  Reply With Quote
Old 29th November 2012, 08:52 PM   #15
Telstar is offline Telstar  Italy
diyAudio Member
 
Join Date: Dec 2007
Location: Italy
Quote:
Originally Posted by wintermute View Post
when looking at the baffle step, plan for a 3-4db reduction in overall efficiency, so to reach your target of 95db efficiency you need 98-99db to start with for the drivers covering the baffle step region (ie your midbass drivers!)
Thanks, Tony. This helped.
So I definitely need two 93dB midranges or a 98-99 one.
Therefore PHL 6" which are 98-100db gets back on frontline, but I need to find one driver from their production with satisfactory FR in my used range.
There is also the PHY-HP H21 LB 15 (added to the first post), which is 8" and most suited in OB (0.59 Qts), anyway I'm pretty sure is well over 300 price, and for OB I fond the need for more cone are = two of them => out of budget.

Quote:
If you crossover at your baffle step frequency to your bass drivers you can then level match for the bass. To get a baffle step frequency of 200Hz you are going to need a wide baffle!
Bass will be active at line-level, because it's absolutely impossible to find a <=12" with low Fs and high efficiency, the TL will be tuned at 25hz and I want an Fs of around 20hz. My favourite bass drivers atm are the scan-speak Discovery either 10" or 12".
If i wanted to go all passive, bass response would terminate at 35hz in the best case unless i use some 15" pro driver and still it wont go as low as the scanspeak (or a peerless).

I dont want to equalize but maybe a little has to be done either at the bottom or the top of the midrange freq window.
I can accept a 250hz XO, but not a 300hz this time.
If basta! simulates normal baffle step, IIRC about 40cm are required for 250hz.
__________________
"The total harmonic distortion is not a measure of the degree of distastefulness to the listener and it is recommended that its use should be discontinued." D. Masa, 1938
  Reply With Quote
Old 29th November 2012, 09:15 PM   #16
diyAudio Member
 
5th element's Avatar
 
Join Date: Oct 2002
Location: England
I second the recommendation for the FST. High efficiency, controlled upper breakup and will work down to 250-300 Hz with a steep xover. It's distortion profile also suits being crossed over high, which is incidentally what B&W designed it for. You will need a notch at 3.5kHz for the one peak/fly in the ointment, but all wider bandwidth/high efficiency drivers are going to require some response shaping if crossed high.

Note that first order electrical crossovers do not often give first order acoustic slopes. Lots of Dynaudio loudspeakers use first order acoustic slopes but often have very complex crossovers in order to achieve them.
__________________
What the hell are you screamin' for? Every five minutes there's a bomb or somethin'! I'm leavin! bzzzz!
  Reply With Quote
Old 29th November 2012, 09:28 PM   #17
diyAudio Member
 
Join Date: Jan 2004
Location: Toronto, ON, Canada
10F/4424G00

Not extremely efficient, but smooth and extended.
  Reply With Quote
Old 29th November 2012, 10:01 PM   #18
Telstar is offline Telstar  Italy
diyAudio Member
 
Join Date: Dec 2007
Location: Italy
Quote:
Originally Posted by Telstar View Post
IIRC about 40cm are required for 250hz.
I correct myself, that would be 45cm, which is a little much for WAF, so probably I have to compensate.

I'll check the 2 drivers recommendations tomorrow.
Thanks
__________________
"The total harmonic distortion is not a measure of the degree of distastefulness to the listener and it is recommended that its use should be discontinued." D. Masa, 1938
  Reply With Quote
Old 29th November 2012, 10:04 PM   #19
Telstar is offline Telstar  Italy
diyAudio Member
 
Join Date: Dec 2007
Location: Italy
Quote:
Originally Posted by 454Casull View Post
10F/4424G00

Not extremely efficient, but smooth and extended.
It's pretty good up to 4khz, but I cannot use 90db. I had checked all scan-speak catalogue as first thing since I'm mating their tweeter.
__________________
"The total harmonic distortion is not a measure of the degree of distastefulness to the listener and it is recommended that its use should be discontinued." D. Masa, 1938
  Reply With Quote
Old 29th November 2012, 10:28 PM   #20
Telstar is offline Telstar  Italy
diyAudio Member
 
Join Date: Dec 2007
Location: Italy
Quote:
Originally Posted by 5th element View Post
I second the recommendation for the FST. High efficiency, controlled upper breakup and will work down to 250-300 Hz with a steep xover. It's distortion profile also suits being crossed over high, which is incidentally what B&W designed it for. You will need a notch at 3.5kHz for the one peak/fly in the ointment, but all wider bandwidth/high efficiency drivers are going to require some response shaping if crossed high.
These are already two things that I don't want to do. I hate those peaks in the voice range and a notch would be mandatory. Add that LF response is almost insufficient for even a 2nd order xo at 250hz.
Efficiency data I have to extrapolate from the graph attached above, but it should be at least 97db for making this driver viable for me. I checked cost and I can't buy 2 per speaker.

There are very few wideband that do not require equalization, such as Volt (too inefficient but otherwise perfect for the job) and the 7" EMS that I listed in the first post -it may beam but it's the only full range I know off that is naturally smooth. But it's lacking of spl in the low-end of my used range.

Quote:
Note that first order electrical crossovers do not often give first order acoustic slopes. Lots of Dynaudio loudspeakers use first order acoustic slopes but often have very complex crossovers in order to achieve them.
Thanks for this advice. I will commission the XO realization to somebody much more expert than yours truly, once I finalized the drivers and rough shape of the speakers.
__________________
"The total harmonic distortion is not a measure of the degree of distastefulness to the listener and it is recommended that its use should be discontinued." D. Masa, 1938
  Reply With Quote

Reply


Hide 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
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
"Best" extended midrange driver below $200 ? youyoung21147 Full Range 48 6th May 2011 03:22 PM
What is meant by 'Extended Cut-off'? Alastair E Tubes / Valves 5 5th May 2005 02:18 PM
1 efficient 12" or 2 (far) less efficient 10"s? beady Car Audio 4 8th August 2004 04:55 AM
high efficient low midrange driver maik Multi-Way 3 27th May 2003 03:27 PM


New To Site? Need Help?

All times are GMT. The time now is 06:20 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2