are these measurements okay? - 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 23rd March 2010, 06:42 PM   #1
diyAudio Member
 
Join Date: Jan 2005
Location: haifa
Default are these measurements okay?

hi,
I'm trying to measure my drivers with HolmImpulse. I am a beginner at this therefore I am not sure if I am measuring correctly. I have attached a picture of the results I received in the program.

The units I am using are:
Tweeter - Morel Supreme 110 (link below)
http://www.morelhifi.com/products/pd...t%20ST1108.pdf

Woofer - MW267 (link below)
http://www.morelhifi.com/products/pdf/mw267.pdf

furthermore, I plan to stuff the cabinets with fiberglass. Currently the cabinets are empty. Will this matter in designing the crossover. My intuition says that I should put the crossover point around 1800 Hz. This is also compliant with my tests using Nuance to test different crossover points while listening to music rather than test signals.

Do these measurements make sense?
If so, how come the tweeter shows up softer than the woofer? The Tweeter is 91.5 decibels while the woofer is 88 dB (by specifications).

Also, after having all the measurements, what would be the next logical step? I'm trying to use speaker workshop, but it is proving to have quite a learning curve.

Thanks for the help,
Eitan Waks
Attached Images
File Type: jpg measurement.jpg (633.0 KB, 61 views)
  Reply With Quote
Old 23rd March 2010, 06:53 PM   #2
Loren42 is offline Loren42  United States
diyAudio Member
 
Join Date: Sep 2008
Location: "Space Coast" Florida, USA
Quote:
Originally Posted by eitanwaks View Post
hi,
I'm trying to measure my drivers with HolmImpulse. I am a beginner at this therefore I am not sure if I am measuring correctly. I have attached a picture of the results I received in the program.

The units I am using are:
Tweeter - Morel Supreme 110 (link below)
http://www.morelhifi.com/products/pd...t%20ST1108.pdf

Woofer - MW267 (link below)
http://www.morelhifi.com/products/pdf/mw267.pdf

furthermore, I plan to stuff the cabinets with fiberglass. Currently the cabinets are empty. Will this matter in designing the crossover. My intuition says that I should put the crossover point around 1800 Hz. This is also compliant with my tests using Nuance to test different crossover points while listening to music rather than test signals.

Do these measurements make sense?
If so, how come the tweeter shows up softer than the woofer? The Tweeter is 91.5 decibels while the woofer is 88 dB (by specifications).

Also, after having all the measurements, what would be the next logical step? I'm trying to use speaker workshop, but it is proving to have quite a learning curve.

Thanks for the help,
Eitan Waks
Greetings.

I would stuff the cabinet. Internal box resonances are going to add to the frequency response graph and confound what you are trying to test.

It looks like you have some room or floor bounce creating some issues with the woofer, but you can't tell until you stuff the box.

1800 Hz may be okay, but you are pushing it a little on the low side, but you can't help that with a 2-way.

What is the polarity relationship of the woofer and the tweeter?

Can you post a schematic of the crossover?

Last edited by Loren42; 23rd March 2010 at 07:00 PM.
  Reply With Quote
Old 23rd March 2010, 07:03 PM   #3
diyAudio Member
 
Join Date: Jan 2005
Location: haifa
these measurements were taken for each driver independently. Currently there is no crossover installed.
I am attaching the schematic of the proposed crossover.
I am also attaching the polarity from the measurements.

Eitan Waks
Attached Images
File Type: jpg polarity.jpg (699.8 KB, 58 views)
Attached Files
File Type: pdf X·over Pro.pdf (23.8 KB, 15 views)
  Reply With Quote
Old 23rd March 2010, 07:32 PM   #4
Loren42 is offline Loren42  United States
diyAudio Member
 
Join Date: Sep 2008
Location: "Space Coast" Florida, USA
Quote:
Originally Posted by eitanwaks View Post
these measurements were taken for each driver independently. Currently there is no crossover installed.
I am attaching the schematic of the proposed crossover.
I am also attaching the polarity from the measurements.

Eitan Waks
1) Look at the net amplitude response (black line)! Reverse your polarity of the tweeter. That is why you have that huge notch in the net amplitude response right at the crossover point. Ideally that should be smooth or a slight bump. Part of the problem is also the phase mismatch (see #3).

2) You need off-axis plots for both drivers. I think 7.5° increments are recommended out to 45° each side of the driver. The idea is to match the crossover point for the woofer and tweeter where the two drivers have the best match in side dispersion.

3) You don't have your phase diagrams shown. Mixing a 1st order and a 3rd order crossover will have some phase mismatch. 3rd order filters produce a 270°*phase shift, first order has a 90° phase shift. Flipping the tweeter polarity will fix that.

Can you try a 2nd order for both drivers? This will keep the phase coherent if you flip the tweeter polarity and compromise on your slopes a little. It will also flatten out the tweeter's high end hill and reduce the effects of the woofer's cone break up.

There are better people than I to advise you on this further, but I think that the advice given so far will get you a little further on the right path. Read the X-Over Pro User Manual for more tips and dig up some information on the web on crossover design. You probably will find some conflicting information, so take the source of information in consideration and keep asking questions!
  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
Lowther - measurements jirka Full Range 61 18th October 2006 09:11 PM
different measurements resident Tubes / Valves 4 17th April 2005 09:04 PM
New DAC with measurements! ojg Digital Source 29 9th March 2004 03:47 PM
amp measurements GAK Tubes / Valves 0 11th February 2004 03:29 PM
Measurements? panos29 Multi-Way 3 20th April 2003 05:07 PM


New To Site? Need Help?

All times are GMT. The time now is 06:29 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