Hello to everyone!
Some 10 years ago, I have built a three way active system consisting of KEF B139 in sealed cabinet, Visaton W130S in dipole cofiguration, and Monacor DT250 tweeter. Crossover is active, 4th order LR, 250Hz and 2500Hz.
So, what's the problem? Well, actually, there is no problem. Everything sounds great, but I thought of upgrading the mid driver, because I guess there are better sounding midranges, as W130s is pretty cheap (although decent) and it could be weak part of the chain. But, I don't know what to look for. For example, Seas MCA15RCY fits even with dimension perfectly to my cabinets. Will it sound better? Why will it sound better? I was told that if I want better results, I should look to drivers with high Qms, not low (Seas and Visaton are both low on Qms). Generally speaking, what would you look for in midrange speaker, beside frequency response?
Should I leave everything as is, and just enjoy the music?
Thanks in advance!
Some 10 years ago, I have built a three way active system consisting of KEF B139 in sealed cabinet, Visaton W130S in dipole cofiguration, and Monacor DT250 tweeter. Crossover is active, 4th order LR, 250Hz and 2500Hz.
So, what's the problem? Well, actually, there is no problem. Everything sounds great, but I thought of upgrading the mid driver, because I guess there are better sounding midranges, as W130s is pretty cheap (although decent) and it could be weak part of the chain. But, I don't know what to look for. For example, Seas MCA15RCY fits even with dimension perfectly to my cabinets. Will it sound better? Why will it sound better? I was told that if I want better results, I should look to drivers with high Qms, not low (Seas and Visaton are both low on Qms). Generally speaking, what would you look for in midrange speaker, beside frequency response?
Should I leave everything as is, and just enjoy the music?
Thanks in advance!
- build quality / consistency
- dispersion at 2500 that's ~similar to the tweeter
- a sleek frame and magnet design that minimises reflections
- aesthetics (particularly if you often see the back of the dipole)
Timothy Feleppa's Pages: Speaker Measurements - Woofers 5" to 8"
The Vifa/Tymphany NE180W-08 6.5" looks and measures very well, and is not too pricey (compared to the similarly sleek Illuminator drivers).
The smaller NE149 might be a better fit to drop into your existing system.
You might find that you spend the money and only get a 1% improvement 😛
Match the dispersion of midrange and tweeter. That means you can either swap the tweeter for one with dipole dispersion or enclose the midrange and put the tweeter in a waveguide.
^Yes, and check the acoustic response and x-o response! A dipole driver behaves differently than closed in lower register, it needs eq and lots of it if you drive it so low.
Baffle width and driver diameter are important to know. First one very much determines the low end response and the latter directivity in upper band.
My suggestion is to first measure and eq each driver's response by on-axis measurements at 1m. Lower xo should be an octave higher around 500Hz un less the baffle is very wide. You should do also horizontal off-axis measurements, to make directivities to match as well as possible! Vertical directivity comes as given... Then check also delay settigs per "way" to get best possible xo summation.
Please study these pages to get deeper understandig of what I wrote above
Dipolplus - Alles über offene Schallwände
Tech
Baffle width and driver diameter are important to know. First one very much determines the low end response and the latter directivity in upper band.
My suggestion is to first measure and eq each driver's response by on-axis measurements at 1m. Lower xo should be an octave higher around 500Hz un less the baffle is very wide. You should do also horizontal off-axis measurements, to make directivities to match as well as possible! Vertical directivity comes as given... Then check also delay settigs per "way" to get best possible xo summation.
Please study these pages to get deeper understandig of what I wrote above
Dipolplus - Alles über offene Schallwände
Tech
User Name "Sealed"
Speaker Directivity "Dipole"
Top reviewed dipole speakers maintain dipole dispersion from woofer through tweeter. Monopole Subwoofers.
Sealed Enclosure:
Consider building a sealed enclosure with the volume adjusted to achieve Qtc ~0.577 for the Visaton W130S. The crossover will need to provide baffle step boost.
NEW BUILD:
Consider building a NEW sealed cabinet with a NEW midrange and NEW tweeter to use with your KEF B139 woofer. This would both allow you to experiment with new driver tech and also compare current dipole vs. sealed polar dispersion patterns. You could always use the NEW TM speakers for desk/bedroom.
A sealed version of Jeff Bagby "Soprano" with 4" + 1" SB_Acoustics drivers would be one reference standard.
==========
Speaker Directivity "Dipole"
Top reviewed dipole speakers maintain dipole dispersion from woofer through tweeter. Monopole Subwoofers.
Sealed Enclosure:
Consider building a sealed enclosure with the volume adjusted to achieve Qtc ~0.577 for the Visaton W130S. The crossover will need to provide baffle step boost.
NEW BUILD:
Consider building a NEW sealed cabinet with a NEW midrange and NEW tweeter to use with your KEF B139 woofer. This would both allow you to experiment with new driver tech and also compare current dipole vs. sealed polar dispersion patterns. You could always use the NEW TM speakers for desk/bedroom.
A sealed version of Jeff Bagby "Soprano" with 4" + 1" SB_Acoustics drivers would be one reference standard.
==========
Sorry Sealed to refloat such an old thread.
I also have a project very similar to yours, and I would like to get some information and some advice. I want to build an active system using some speakers that I have around, for the bass I will use a pair of kef b139 (sp1044) and for the midrange I have a pair of Audax HM170CO, for the treble I'm thinking in Fountek ribbons, the Neo CD3 or CD3.5h.
Any comment? crossover points? dipole or sealed mid? dbx, behringer, others for the active filter... Thank you in advance
I also have a project very similar to yours, and I would like to get some information and some advice. I want to build an active system using some speakers that I have around, for the bass I will use a pair of kef b139 (sp1044) and for the midrange I have a pair of Audax HM170CO, for the treble I'm thinking in Fountek ribbons, the Neo CD3 or CD3.5h.
Any comment? crossover points? dipole or sealed mid? dbx, behringer, others for the active filter... Thank you in advance
Kef B139 in sealed box
Hi. Which volume for the B139 in sealed box? Which type and quantity of absorbent?
I'm going to make a subwoofer for Kef Reference 101, electronically filtered at 150-250 Hz (frequency to be determined accordingly to sonic results)
All the examples of B139 in sealed enclosures have passive crossover, and this means that a resistance around 1,8 ohm, due to inductors, is added. For all of them the box has a volume around 60 litres. Without this added resintance the volume should probably be modified, but I don't know how.
Thanks for your help
Best regards
Roberto
Hi. Which volume for the B139 in sealed box? Which type and quantity of absorbent?
I'm going to make a subwoofer for Kef Reference 101, electronically filtered at 150-250 Hz (frequency to be determined accordingly to sonic results)
All the examples of B139 in sealed enclosures have passive crossover, and this means that a resistance around 1,8 ohm, due to inductors, is added. For all of them the box has a volume around 60 litres. Without this added resintance the volume should probably be modified, but I don't know how.
Thanks for your help
Best regards
Roberto