Some off-topic split to here - https://www.diyaudio.com/community/threads/cabs-ribbon-speaker-idea.401904/
OB update! My speakers from post 4160 got a bit of a refresh today. I took a bunch of new measurements of the drivers with and without the crossover, with and without the other drivers together, and then with my Flex Eight DSP.
The result of today’s tinkering is the attached picture (from my listening position). This is using the analog crossover I made, plus a few minor tweaks, and then a few PEQ tweaks to the input signal with the DSP.
This is sounding VERY good. A noticeable improvement from the previous iteration, which was a little boomy around 80-120 Hz, weak from 3-8K, and bright above 12K.
Earlier when I was using the full on multi-channel DSP crossover with three amps, the gain and noise was too high. Although that was likely due to beginner error and bravado, this setup is just as noise free (by my ears) as just using the analog crossover without the Flex Eight. Good thing, too, because this fancy piece of equipment was languishing for a while.
Happy weekend futzing to all!
The result of today’s tinkering is the attached picture (from my listening position). This is using the analog crossover I made, plus a few minor tweaks, and then a few PEQ tweaks to the input signal with the DSP.
This is sounding VERY good. A noticeable improvement from the previous iteration, which was a little boomy around 80-120 Hz, weak from 3-8K, and bright above 12K.
Earlier when I was using the full on multi-channel DSP crossover with three amps, the gain and noise was too high. Although that was likely due to beginner error and bravado, this setup is just as noise free (by my ears) as just using the analog crossover without the Flex Eight. Good thing, too, because this fancy piece of equipment was languishing for a while.
Happy weekend futzing to all!
Attachments
Look at these eminence. I might try them somedayI used a double layer of 19 mm MDF with steel rails for increased stiffness, and some bitumen sheets for a little dampening. It turned out very good, with no audible resonances, and very little vibration can be felt on the baffles themselves.
As mentioned before, the finished speaker weighs about 75 kg. The moving mass of the four Eminence Delta 12B woofers I used is just 128 grams. The 1/125 rule is satisfied(1/586)
View attachment 1198003
I think some of the trick is to select drivers with low Mms. I do remember trying the opposite, with a Beyma 21" that had 370 grams moving mass. That did not work so well in a small and light baffle.
http://www.loudspeakerdatabase.com/Eminence/LEGEND_BP1525
I tried them and they are working really well above 70hz. below there is no enough cone travel for high SPL. Problem solved with two RSS390HF.
https://www.diyaudio.com/community/threads/ultimate-open-baffle-gallery.123512/post-6669937
https://www.diyaudio.com/community/threads/ultimate-open-baffle-gallery.123512/post-6669937
If we look at the frequency response and impedance of the Eminence Alpha 15A and BP 1525, we see that the latter has some cone breakup around 3-400 Hz which the Alpha 15A doesn't have. This, and slightly lower Mms is why I like the Alpha 15A better for mid bass, where it's low Xmax is not a problem.
BP 1525
Alpha 15A - smoother impedance indicating less cone breakup.
BP 1525
Alpha 15A - smoother impedance indicating less cone breakup.
A 15" driver can in many cases work well up to 1 kHz. There are many examples of such designs.
I did test a single Eminence Alpha 15A in dipole as midbass up to 500 Hz. Can't say that I lacked any "punch" or transient impact compared to my current dipoles using four Eminence Delta 12A, which have higher sensitivity and lower Qts. I'm not at all so sure that Qts has anything to do with the subjective impression of transient response when its not being used down to Fs.
I did test a single Eminence Alpha 15A in dipole as midbass up to 500 Hz. Can't say that I lacked any "punch" or transient impact compared to my current dipoles using four Eminence Delta 12A, which have higher sensitivity and lower Qts. I'm not at all so sure that Qts has anything to do with the subjective impression of transient response when its not being used down to Fs.
I don't think graph shows directivity. Measurements need to be 0 to 90 degrees with 10 degrees interval. Those graphs will show significant beaming
https://www.erinsaudiocorner.com/loudspeakers/jbl_m2/
https://www.erinsaudiocorner.com/loudspeakers/jbl_m2/
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I am currently re-jigging my P17s that were built by someone else. I am having difficulty with the crossover for the woofer due to what has been done before. Fikus's drawing for the crossover (woofer) has both terminals shown as + yet he says bass is in opposite polarity. One of them must be - but I am not sure which one.I bought a pair of Lampizators with Saba green cones a few years ago from a guy on another forum. I didn't really get on with them and they were put aside as I got another pair of OBs. I thought that the cohesion between the bass and mid/treble was not to my liking or not quite right.
Last week I thought that I would give them another go by using the mid/treble with the bass from the other OBs. They would clearly need a little tweaking to make them gel given the sensitivity, but I had forgotten just how open the mid/treble is, great for acoustic guitar. When I took them out it sounded somewhat dull
http://lampizator.eu/speakers/projects/P17/Endorphine from Kingston Kitchen.html