The L Cao thread was moved to the commercial area, however I
promised some more data, and if you are like me, you'll never see
this over there....
This is a NF / FF composite of the L Cao 8" with an Eminence Beta 15
in an open baffle with 6 dB of EQ at 20 Hz and -3 dB broad notch
at 3 KHz. The individual responses of the drivers with the crossover
are shown in dotted lines.
Any questions?
promised some more data, and if you are like me, you'll never see
this over there....
This is a NF / FF composite of the L Cao 8" with an Eminence Beta 15
in an open baffle with 6 dB of EQ at 20 Hz and -3 dB broad notch
at 3 KHz. The individual responses of the drivers with the crossover
are shown in dotted lines.
Any questions?
Attachments
ttan98 said:
At $110, yes I think so. It falls roughly in the category of Fostex and
Audio Nirvana, and is comparable. All FR drivers have a couple of warts
here and there, and this is not an exception.
Probably the main attraction is lack of a whizzer, which seems to
be disliked by some. I am agnostic on that subject, but the L CAO
does get some decent top end without one.
By the way, the crossover filters are 12 dB/oct, set around 70 Hz on
the Low Pass, 150 Hz on the High Pass and are in phase.
The FR driver is mounted at a 36" height, and the baffle is held up
at about 10 degrees tilt by two 2' high by 1' deep rear side panels.
I do think it makes for a very pleasant system.
And here's the impedance curve of the FR in the baffle:
Attachments
>>> The Beta comes with a magnet.
Yes, the Alpha 15 has a pretty small magnet. I prefer the look of the Beta from the back and the front. But the Alpha's do the trick in an H-Frame. How do you have the Beta's hooked up? H-Frame, ported??? Even tho they don't spec out to work in an OB as well as the Alpha's i wonder how they would sound?
They are both black and round.
Yes, the Alpha 15 has a pretty small magnet. I prefer the look of the Beta from the back and the front. But the Alpha's do the trick in an H-Frame. How do you have the Beta's hooked up? H-Frame, ported??? Even tho they don't spec out to work in an OB as well as the Alpha's i wonder how they would sound?
They are both black and round.
Nelson,
Deciding between a higher Qts driver or a lower Qts driver but with EQ is an interesting trade-off. If you select a high Qts driver like the Alpha 15A the magnet is smaller and the cost is a little less compared to the Beta 15A with EQ. The question I have concerns the following scenerio, selecting the Beta 15A with a lower Qts and then adding EQ to push the bass up don't you end up at the same performance point? If both options provide "flat" bass to 40 Hz in your OB does it matter sound wise which path you take? Both drivers should still be working as a single degree of freedom system moving the same amount with rigid cone motion to produce the same SPL/W/m. For bass frequencies below 200 Hz and in a common moderately sized baffle, what advantages or disadvantages do you see using a Beta 15A and EQ over an Alpha 15A?
Deciding between a higher Qts driver or a lower Qts driver but with EQ is an interesting trade-off. If you select a high Qts driver like the Alpha 15A the magnet is smaller and the cost is a little less compared to the Beta 15A with EQ. The question I have concerns the following scenerio, selecting the Beta 15A with a lower Qts and then adding EQ to push the bass up don't you end up at the same performance point? If both options provide "flat" bass to 40 Hz in your OB does it matter sound wise which path you take? Both drivers should still be working as a single degree of freedom system moving the same amount with rigid cone motion to produce the same SPL/W/m. For bass frequencies below 200 Hz and in a common moderately sized baffle, what advantages or disadvantages do you see using a Beta 15A and EQ over an Alpha 15A?
badman said:
Actually, the notch depth was based on listening. Routinely the
perception of FR drivers in this region is more forgiving than on-axes
1M measurement.
freddi said:
This is a No-Box baffle as I understand the concept. The front-
to-back distance is increased a bit by the side supports as described.
After years of playing with FR drivers I have learned to spend the
extra couple of bucks ($8 in this case) on a better magnet and maybe
a little EQ. True, you can get mechanically similar results, but IMHO
the sound is really not the same.
Lowthers, which is a magnet cult if there ever was one, provides the
best example. Depending on what you're looking for, there is
a Lowther magnetic motor to meet your needs. Ceramic, Neodymium,
Alnico, Ticonal, Permendur. Medium, Large, SuperSized and Field Coil.
Voice coils regular, and over-hung (Oh, Baby!).
As the sensitivity of the motor and the exotic-ness of the magnet
goes up, the measured and perceived response alters. Using the PM6
type as an example, from about 200 Hz to 10 KHz the PM6C @8ohms
fits in a 20 dB window. The PM6A @8ohms fits a 15 dB window. The
PM6A @16ohms fits a 10 dB window, and the PM5A (bigger magnet)
@ 16 ohms fits a 15 dB window.
A pair of PM4A's (monster magnet) was deposited on my floor this
morning. I will get some ruffians to carry them to the listening room
real soon now.
IMHO so far the PM6A @ 16ohms provides the best un-equalized
experience, but if you equalize all of them with low Q filters to meet
its 10 dB window, the subjective quality starts lining up as a
function of magnet expense.
What do I mean by subjective quality? That's an individual thing,
but as a general rule a high quality driver makes me go through a
lot of my record collection in one sitting. What quality am I hearing?
More detail for sure - things come out in sharper relief, the same
little bits that you don't notice with more ordinary drivers.
Similar effects with the Feastrex, and I'll let you know about the
PM4A's.
Have I even tried the Alphas? Naaaaah.
Nelson,
Sorry, my question was not clear.
I am totally focusing on the 15" bass driver for the OB, the trade-offs between the Alpha 15A and the Beta 15A with EQ. For the frequency range from 40 Hz to 200 hz what are the theoretical pro's and con's of using either of these Eminence drivers. In my simplified understanding, it would seem that the EQ applied to the Beta 15A is driven by trying to make it perform like the Alpha 15A. I am looking for some other advantage that would justify spending the extra money and equipment to implement the Beta 15A and an EQ circuit. Granted the cost difference seems small, but for some it may not be trivial. I am looking for a list of trade-offs between the two types of bass drivers (Qts > 1 and Qts < 0.7 with EQ) and the impact/benefit of EQ so people can make intelligent decisions (including me).
As far as the different varieties of Lowther drivers, I have a few and have my opinions on my favorite versions. Again in my opinion thay are all great drivers and I like different models for different reasons. To be honest, my least favorite are the A series. I like the DX series for performance and the C series for cost. Unfortunately, a couple of the more exotic ones that I wanted to try are out of the picture due to lack of funds. I will try top limp forward with my current collection.
Sorry, my question was not clear.
I am totally focusing on the 15" bass driver for the OB, the trade-offs between the Alpha 15A and the Beta 15A with EQ. For the frequency range from 40 Hz to 200 hz what are the theoretical pro's and con's of using either of these Eminence drivers. In my simplified understanding, it would seem that the EQ applied to the Beta 15A is driven by trying to make it perform like the Alpha 15A. I am looking for some other advantage that would justify spending the extra money and equipment to implement the Beta 15A and an EQ circuit. Granted the cost difference seems small, but for some it may not be trivial. I am looking for a list of trade-offs between the two types of bass drivers (Qts > 1 and Qts < 0.7 with EQ) and the impact/benefit of EQ so people can make intelligent decisions (including me).
As far as the different varieties of Lowther drivers, I have a few and have my opinions on my favorite versions. Again in my opinion thay are all great drivers and I like different models for different reasons. To be honest, my least favorite are the A series. I like the DX series for performance and the C series for cost. Unfortunately, a couple of the more exotic ones that I wanted to try are out of the picture due to lack of funds. I will try top limp forward with my current collection.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.