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

Suitable midrange cone, for bandpass mid in Unity horn.
Suitable midrange cone, for bandpass mid in Unity horn.
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 5th April 2018, 08:13 PM   #2221
bwaslo is offline bwaslo  United States
Old guy with soldering iron
diyAudio Member
 
bwaslo's Avatar
 
Join Date: May 2006
Location: Portland, Oregon!
Suitable midrange cone, for bandpass mid in Unity horn.
As nc535 sez, don't underestimate the value of drivers radiating from very close together without directivity jumps.
__________________
[W9MJE] Horn spreadsheet SynergyCalc/; SmallSyns SmallSyns;
Crossover design Xsim; Depot diffusor super-easy diffusors
  Reply With Quote
Old 5th April 2018, 08:21 PM   #2222
IG81 is offline IG81  Canada
diyAudio Member
 
IG81's Avatar
 
Join Date: Feb 2008
Yeah, Bwaslo's SEOS15 thread is part of what piqued my interest. I haven't read as much of it as I'd like though, it's quite long.

So the midrange is played below the waveguide's lowest frequency? It would then basically not matter that pattern control is lost, as it would widen anyway when crossing to a woofer, but now you just cross lower and are closer to or within -wavelength to the woofer. Does that sound about right?

Just as a thought exercise, if a (theoretical) compression driver could play say 600Hz-20kHz on the QSC or SEOS, what would the unitized waveguide have over it, assuming the mids to also would cross at 600Hz?

Bwaslo, what do you cross your SEOS mids at to the 6FE100 on your SmallSyns? I should check your thread again!

Last edited by IG81; 5th April 2018 at 08:25 PM.
  Reply With Quote
Old 5th April 2018, 08:52 PM   #2223
bwaslo is offline bwaslo  United States
Old guy with soldering iron
diyAudio Member
 
bwaslo's Avatar
 
Join Date: May 2006
Location: Portland, Oregon!
Suitable midrange cone, for bandpass mid in Unity horn.
It would matter, but you have to trade off size unless you have a big room and tolerant partner. I also prefer not to look up and see a massive structure reminding me that I'm a hifi nut! Small Syns (and some other syn designs here on diyaudio) can be placed in a room that you can still feel comfortable in. Doing a midrange helps keep all the changeovers smoother.

You can space the woofers from each other so that the two extend the horizontal directivity down a little lower if you blend them with the midranges as the directivity falls off. An advantage of using mulitway instead of a driver that could go 600Hz-20kHz is that the offset drivers of a Unity/Synergy have an acoustic lowpass filter blocking radiation of their out-of-band distortion junk, not a minor consideration in my opinion.

This is from an early version of the crossover, but pretty similar to the final --

simulated.png
__________________
[W9MJE] Horn spreadsheet SynergyCalc/; SmallSyns SmallSyns;
Crossover design Xsim; Depot diffusor super-easy diffusors

Last edited by bwaslo; 5th April 2018 at 08:54 PM.
  Reply With Quote
Old 10th May 2018, 05:12 PM   #2224
fotsinijts is offline fotsinijts
diyAudio Member
 
Join Date: Dec 2015
I found some Altec Lansing full range drivers (4 total) that are used in computer speakers. I was always really fond about them and since I got for I will lasercut a adaptor to fit one of my synergy pairs to see how they sound.

I'm hoping they will play way lower than the celestion tf0410mr.

One thing I dislike is the surrounding of the cone which is not paper.
Attached Images
File Type: png IMG_7004.PNG (764.9 KB, 429 views)
File Type: jpg IMG_7005.jpg (603.1 KB, 428 views)
  Reply With Quote
Old 11th February 2019, 06:19 PM   #2225
njones is offline njones  United States
diyAudio Member
 
Join Date: Sep 2013
Location: Wisconsin
Default Help with woofer port size for synergy

Question for those who have more experience with synergy horns than I:

I'm modifying my synergy horns (again) to reduce the air volume behind the mid and woofer ports and was trying to determine the optimal port size for the woofers. I am using Dayton PA165 woofers and GRS 5" sealed back mids.

They are Approx. 60x90 and slightly larger than BWaslo's default size using his spreadsheet, so around 27" wide by 17" high.

I know its hard to say without exact specs and simulating them in hornresp, and not trying to get out of "doing the work" but honestly I have not been able to figure out how to model them with any level of confidence.

Does anyone have a ballpark estimate on optimal port sizes for mids and woofers? Tried different port sizes on a test baffle and found that 1/2" with some filler seemed to work the best.

I filled the ports with bondo and have re-cut them 1/2" for the mids and 1-3/8" for the woofers (which I think may be too small so I was planning on extending them out pill shaped).

I placed the ports where circumference of the horn is equal to the wavelength 1200Hz for the mids and 350Hz for the woofers.

Is there a rule of thumb on the woofer port size? I thought I recall at least 20% of Sd but I realize that my old 3/4"x4" slot ports were under that amount.

Also I have cut 1-3/8"x1/2" length ports into the sidewalls to get more bass extension however yet again I have no idea if this is even close to being right although WinISD looks like that works for around 2 cubic foot enclosure vented. (yet again, not sure on the exact volume of air behind the horn but estimating it must be a few cubic feet, argh).

Here is the thread I started on these:
Synergy Horn build thread - The Dreadnoughts


Thanks in advance anyone who can help with this!
  Reply With Quote
Old 11th February 2019, 06:44 PM   #2226
Patrick Bateman is offline Patrick Bateman  United States
diyAudio Member
 
Patrick Bateman's Avatar
 
Join Date: Oct 2006
Location: San Diego
In the Danley SH50, the midrange taps are 3/4" in diam, and they're located 3.5" from the throat.

In the Waslo Cosyne, the midrange taps are 5/8" in diam, and they're located 2" from the throat.

I haven't used hornresp to simulate a Unity horn in ages, basically I just copy the Danley geometry. I have to bring the taps in a bit closer because I am crossing over higher than Danley is.

In my experience, the only way you can really screw up the midrange taps is if you put the mids way too far away. If you're off by an inch or half an inch, it's not the end of the world.

Click the image to open in full size.

Here's an example of how you can screw it up.

In the Unity horn that's on the left, the gap from the throat to the midrange taps is about five inches. That's not an impossible gap; for instance Sound Physics Labs sold a Unity horn that used a BMS compression driver and an 8" woofer, named the "SPL Runt."

The reason that it didn't work for me was threefold:

1) I was using a tiny little BMS 4540ND compression drive. A big gap requires a low xover, and the 4540ND couldn't do it.

2) I was using a "hifi" midrange that didn't have a low QES. For instance, the SPL Runt used a prosound woofer, with a low QES, and the low QES allows you to play the midrange higher. (See page one of this thread.)

3) It's easier to cross over lower with a narrow beamwidth horn. For instance, a 90x90 horn is "working" 4x as hard as a 45x45 horn, because the pattern is wider.

So basically I'd painted myself into a corner. My beamwidth, compression driver, and midrange were all wrong. I trashed the project.

TLDR: do what Danley does
  Reply With Quote
Old 11th February 2019, 06:55 PM   #2227
njones is offline njones  United States
diyAudio Member
 
Join Date: Sep 2013
Location: Wisconsin
FYI, the Datyon PA165 woofers have a cone surface area of 18.72 cu. in.

a 3/4"x4" length port (the old port) was 2.875 cu. in.

2.875/18.72=.15 or 15% of Sd

a 1-3/8" port is 1.48 cu. in. which amounts to around 8% of Sd (!) thinking this is too small...
  Reply With Quote
Old 11th February 2019, 07:22 PM   #2228
Patrick Bateman is offline Patrick Bateman  United States
diyAudio Member
 
Patrick Bateman's Avatar
 
Join Date: Oct 2006
Location: San Diego
Quote:
Originally Posted by fotsinijts View Post
I found some Altec Lansing full range drivers (4 total) that are used in computer speakers. I was always really fond about them and since I got for I will lasercut a adaptor to fit one of my synergy pairs to see how they sound.

I'm hoping they will play way lower than the celestion tf0410mr.

One thing I dislike is the surrounding of the cone which is not paper.
The midrange drivers in a Unity horn are basically "filler drivers", they cover a narrow bandwidth.

Whenever I've tried to make them play lower, I ran into a series of challenges:

1) The big issue is the volume of air that's in the chamber. The bigger the chamber, the lower you have to cross the mids over, and that puts a lot of strain on the compression driver. To get that Unity horn magic you have to massage the crossover slopes and the frequency response in the octave of 1khz - 2khz. Basically if your chambers force you to use a low xover point on the tweeter, you may be forced to use a steep slope, which makes it challenge to get the phase right.

2) The other issue is that excursion can destroy your midranges. I've trashed quite a few mids that way.
  Reply With Quote
Old 11th February 2019, 07:24 PM   #2229
Patrick Bateman is offline Patrick Bateman  United States
diyAudio Member
 
Patrick Bateman's Avatar
 
Join Date: Oct 2006
Location: San Diego
Quote:
Originally Posted by njones View Post
FYI, the Datyon PA165 woofers have a cone surface area of 18.72 cu. in.

a 3/4"x4" length port (the old port) was 2.875 cu. in.

2.875/18.72=.15 or 15% of Sd

a 1-3/8" port is 1.48 cu. in. which amounts to around 8% of Sd (!) thinking this is too small...
Why are the ports so long?

I like using super long ports, but I'm 3D printing the chambers so I can "cheat" a little. If you're just drilling a hole into plywood, a 4" long port won't work
  Reply With Quote
Old 11th February 2019, 08:34 PM   #2230
nc535 is offline nc535
diyAudio Member
 
Join Date: Apr 2011
Quote:
Originally Posted by njones View Post
Question for those who have more experience with synergy horns than I:

I'm modifying my synergy horns (again) to reduce the air volume behind the mid and woofer ports and was trying to determine the optimal port size for the woofers. I am using Dayton PA165 woofers and GRS 5" sealed back mids.

They are Approx. 60x90 and slightly larger than BWaslo's default size using his spreadsheet, so around 27" wide by 17" high.

I know its hard to say without exact specs and simulating them in hornresp, and not trying to get out of "doing the work" but honestly I have not been able to figure out how to model them with any level of confidence.

Does anyone have a ballpark estimate on optimal port sizes for mids and woofers? Tried different port sizes on a test baffle and found that 1/2" with some filler seemed to work the best.

I filled the ports with bondo and have re-cut them 1/2" for the mids and 1-3/8" for the woofers (which I think may be too small so I was planning on extending them out pill shaped).

I placed the ports where circumference of the horn is equal to the wavelength 1200Hz for the mids and 350Hz for the woofers.

Is there a rule of thumb on the woofer port size? I thought I recall at least 20% of Sd but I realize that my old 3/4"x4" slot ports were under that amount.

Also I have cut 1-3/8"x1/2" length ports into the sidewalls to get more bass extension however yet again I have no idea if this is even close to being right although WinISD looks like that works for around 2 cubic foot enclosure vented. (yet again, not sure on the exact volume of air behind the horn but estimating it must be a few cubic feet, argh).

Here is the thread I started on these:
Synergy Horn build thread - The Dreadnoughts


Thanks in advance anyone who can help with this!
I think an HR simulation can give you a better idea than any one who hasn't done HR sim for your set of parts and waveguide. If you have done a sim but then found it doesn't correlate with measurements on a proto, then figure out why. What did you fail to account for? Its easy to miss things like including a throat chamber to account for the fact that the reflection from the mid port is not from the throat of the horn but from the phase plug back inside the CD. Its easy to mis-estimate the air under the mid cones,etc. (not that hard to measure filling the cone with rice and then pouring the rice into a measuring cup). If each parameter in the simulation is accurate then so should be its results.

Once you get a correlation or a fudge factor, then you can cut and try in simulation instead of bondo until you've found something that works.
__________________
My Synergy Corner Horns and Bass Bins
http://www.diyaudio.com/forums/multi...bass-bins.html
  Reply With Quote

Reply


Suitable midrange cone, for bandpass mid in Unity horn.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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Bandpass Woofer/Midrange? m@ Multi-Way 5 25th March 2006 03:10 AM
looking for 6.5inch woofers suitable for a 30 - 35Hz horn... and a small horn too :P SkinnyBoy Multi-Way 24 13th February 2004 06:06 AM


New To Site? Need Help?

All times are GMT. The time now is 10:32 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Copyright ©1999-2019 diyAudio
Wiki