Dipoles don't have a 6 dB baffle step, but a 6 dB/oct roll-off. This means, that the baffle step does not end after 6 dB, but falls off infinitely. That's one of the big advantages of dipoles
still in the trial and error phase of things, as i have made a couple of measurment mics, but none of them measure the same, so i dont trust them completely
based on listening and the similarities of the different measurements i have made, i have made a temporary setup that sounds good enough for me to live with until i can get my hands on a proper mic.
i have a 150hz LR 12 db/oct low pass on the woofers, and run the L.cao fullrange.
the woofers has a 12db gain at 55hz (Q 1.9)
the l.cao has a peak of -5 at 1800hz (Q 1,3)
in addition i have added -4db to the treble controls on my kenwood 700c pre starting at 3000hz to counteract the rising response of the 8".
(the reason i did it on the kenwood was because it both sounded and measured correct, and i didnt want to fiddle with the minidsp EQ anymore
-bjarne
Just one more question...
How does the top end sound with these drivers? Are they nice and crisp, or are they rather rolled off like a lot of 8" drivers?
i find the treble perfectly adequate, but then my last speakers were esl63's, so i am probably just used to rolled off treble
i'm sure a tweeter would make a good addition, but i prefer to keep it simle for now.
So after lot`s of mails and shipping i`ve got repaired speakers yesterday. And both are sounding quite the same as it should be.
I think they need a lithe break in, because they were a little bit frozen, but first impression is quite good. For my taste the terrible is quite fine, but i need a little more. I took a sipe HT with which is 4 ohm and a 1,5uF for testing. Not bad, but i will report.
Regards, Michael
I think they need a lithe break in, because they were a little bit frozen, but first impression is quite good. For my taste the terrible is quite fine, but i need a little more. I took a sipe HT with which is 4 ohm and a 1,5uF for testing. Not bad, but i will report.
Regards, Michael
unfortunately my computer died, and with it, my main music source, so the project has been standing still for a couple of months now
the last thing i did was revisiting the use of a conventional baffle, and i must admit, i preferred it to the no-baffle version, as it allowed me to lower the crossover of the woofers.
i guess if i want to make a baffleless speaker, i will need to invest in better woofers with the ability to cross higher
the next step will probably be building a new baffle, and see if i can lower the crossover without having to eq the heck out of the l cao to meet the woofers.
i'd be very interested in seeing some real world frequency plots for these drivers as they're on my short list of affordable alnico play things. the provided responses look far too good to be true.
also if anyone would like to provide a good quality video of them playing some music that would be nice.
also if anyone would like to provide a good quality video of them playing some music that would be nice.
I haven't gotten around to unboxing my alnicos, but I don't expect a lot
of difference between the earlier ones.
Curve shown here is in 3 x 5 ft OB with an Eminence 15 beta (you can see
the crossover and sum). At 1M with 1/3 octave smoothing. There is
a bit of a peak at 3 KHz, but you can notch it out. No worse than most.
of difference between the earlier ones.
Curve shown here is in 3 x 5 ft OB with an Eminence 15 beta (you can see
the crossover and sum). At 1M with 1/3 octave smoothing. There is
a bit of a peak at 3 KHz, but you can notch it out. No worse than most.
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I haven't gotten around to unboxing my alnicos, but I don't expect a lot
of difference between the earlier ones.
Curve shown here is in 3 x 5 ft OB with an Eminence 15 beta (you can see
the crossover and sum). At 1M with 1/3 octave smoothing. There is
a bit of a peak at 3 KHz, but you can notch it out. No worse than most.
have you still got the older model handy? if possible could you post a recording of them playing?
what is the dustcap made of? it looks like its made of permeable material in some of the pictures. is it solid? i was planning on butchering a pair with phase plugs and the EnABL process.
would you recommend a pair of these over a similarly priced speaker from one of the more mainstream speaker manufacturers?
not sure what it is made of, but it is some kind of translucent mesh.
this is the best picture i have of it:
An externally hosted image should be here but it was not working when we last tested it.
I haven't gotten around to unboxing my alnicos, but I don't expect a lot
of difference between the earlier ones.
Curve shown here is in 3 x 5 ft OB with an Eminence 15 beta (you can see
the crossover and sum). At 1M with 1/3 octave smoothing. There is
a bit of a peak at 3 KHz, but you can notch it out. No worse than most.
This looks quite good to me. Is this W/O the recommended notch filter? A couple of questions regarding x-over if I may?
I have Rythmik servo amps, GR Research 12" x 2 / channel in "H" OB baffle. On top I presently use Fostex FF85K x 4 /channel OB, Peter Daniel F5 or Helder 2020 Tripath or SE EL34 tube. Top end is rolled off by single cap (PLLXO) at 150hz. Reason for replacing Fostex is FS is mainly because FS 122hz even with four in open baffle rolloff starts around 200-300hz and as a mini linesource when you stand up the HF's diminish substantially.
Has anyone tried Marchand XM 46 PLLXO? I had a thier XM9 some years ago, but was a little noisy and music lost some PRAT. Not keen on electronic since.
Any other PLLXO options ?
Is 150hz reasonablee for the L.Cao on 15" baffle?
Gary
That curve was notched 3 dB at 3 KHz. You can make it flatter, but I did
not find that it sounded as good - it's the old "halfway rule".
Thanks for the quick response. I was originally going for a pair of PM6A's do you feel this driver is worth pursuing compared to the much costlier Lowther? I was assured by Kevin at Valab they have changed the packaging, he told me they had two incidents with the old, and that he matches the drivers, as advertised, which would show if their were any problems with the drivers. Incidentally he did not originally sell DerTrommler drivers although replaced a driver for him.
Gary
i think they are a pretty good option for low cost OB bass.
they are very sensitive at 99db, have a strong magnet, solid basket and Qts of 0,42
xmax is a bit low if you plan to make them play lower then 35hz, but thats not what OB is suited for anyway.
they produce way more textured and punchy bass then the eminence alpha, and doesnt sound as meaty/boomy, but need more EQ,
i wouldnt cross them higher then 150hz.
Thanx!
Im considering connecting to the active xover on my hypex Hs500 to the amplifier driving them.
Maybe i should consider a smaller element (12")?
Tried eminence?
Been checking, and i see that u had some problem with bassresponse.
My plan is to build a "kind of" H-baffle, that ideal the same shape as the fa22-baffle.
I cant see any problems with using the 1550, except of a little dip in the 150hz area a frequency which is within the required 3db range
My plan is to build a "kind of" H-baffle, that ideal the same shape as the fa22-baffle.
I cant see any problems with using the 1550, except of a little dip in the 150hz area a frequency which is within the required 3db range
I was awaiting feedback on the L.Cao alnico drivers, but it seemed to have died, so I purchased a pair from Valab. Kevin communicates, matches/tests drivers and they arrived in 2+ weeks to Toronto area. Very well packaged and no issues. I have about 250+ hours on them. Drive them with modified Tom McNally KT-77 SE tube amp.~ 5w or so. I have 2 pairs of coupling caps, FR and ~170hz 1st order that can be switched on the fly, consider it PLLX-over. FR is used for thin sounding recordings.
Impressions: They are detailed, fast, open, and yet smooth. I am using the supplied parallel filter. Parts are decent, but upgrade will be coming. They image well, have very good dynamics and detail. My previous 4 x Fostex FF85K went to 32khz and I don't perceive any loss of air, but the the L.Cao's put out more treble as NP said of the ceramic version. I used to make my own magnetic ribbon speakers, FR, Tweeter/Mids but dynamics and dispersion are really tuff to get right. These do it right and very well.They also are not bass shy on my temporary 13.5" x 25" baffle above the OB subs. In my smallish 14' x 22' room they play louder than I can listen too.
I recommend them without reservation, price considered, but have never heard Lowther in OB. My before and after pic.'s
Impressions: They are detailed, fast, open, and yet smooth. I am using the supplied parallel filter. Parts are decent, but upgrade will be coming. They image well, have very good dynamics and detail. My previous 4 x Fostex FF85K went to 32khz and I don't perceive any loss of air, but the the L.Cao's put out more treble as NP said of the ceramic version. I used to make my own magnetic ribbon speakers, FR, Tweeter/Mids but dynamics and dispersion are really tuff to get right. These do it right and very well.They also are not bass shy on my temporary 13.5" x 25" baffle above the OB subs. In my smallish 14' x 22' room they play louder than I can listen too.
I recommend them without reservation, price considered, but have never heard Lowther in OB. My before and after pic.'s
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