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fEARful Part Twelve (12)
- Thread starter greenboy
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Are those wood screws? What size? Length?
Using something like Loctite Blue should keep together anything threaded on a metal bolt.
lelandcrooks
Commercial User
Recex screws don't require a pilot hole. The serrated thread and drill point will not split plywood. If it does, you're too close to the edge. Nothing wrong with using lockwashers on them, but it's unnecessary. The ones I have the head is serrated also to lock in place. If you do some research into the thread design they are specifically designed to withstand shock and vibration.
Plugged my 15/6/1 into my Crown XLS and played some music from my XBOX since that is the only line out level device I have in the house until my preamp arrives and.... my 3015LF rattles at low volume. 
It rattles if you tap the cone. It rattles if you bump the edge of the driver on a soft surface. The rattle is coming from somewhere inside the coil/magnet structure.
So I guess I have to send it back and wait for a replacement.
It rattles if you tap the cone. It rattles if you bump the edge of the driver on a soft surface. The rattle is coming from somewhere inside the coil/magnet structure.
So I guess I have to send it back and wait for a replacement.
check the leads that run from the binding post through the cone - a gentle readjustment and maybe a drop of visco-elastic glue it fix ya right up.
Except for grill and possible driver problem.... 
Does it happen when the driver is out of the box? In this situation some medium-low volume music should have a very thin sound, if the driver itself rattles you will hear it more clearly than when iti is mounted in the box.
If the rattle dissapears then it is the box or it is related to the way the driver is mounted on the box.
Just in case you did not try.
Very nice cab, by the way.
I am closer to finish my 2 non-Fearful 1x15's, I am lokking forward to doing my first tests.
If the rattle dissapears then it is the box or it is related to the way the driver is mounted on the box.
Just in case you did not try.
Very nice cab, by the way.
I am closer to finish my 2 non-Fearful 1x15's, I am lokking forward to doing my first tests.
Thank you 
Yes, I tried it outside the box, too. I disconnected it and tapped the cone and you can hear the rattle in the back of the speaker. Definitely something not right back there.
So I have packaged it up to go back to the supplier.
From the little I heard with the cab together I can't wait to get the replacement speaker. It sounded SO good, even with the odd rattling. If your cabs have 3015LF's in them I am sure you will be satisfied
Yes, I tried it outside the box, too. I disconnected it and tapped the cone and you can hear the rattle in the back of the speaker. Definitely something not right back there.
So I have packaged it up to go back to the supplier.
From the little I heard with the cab together I can't wait to get the replacement speaker. It sounded SO good, even with the odd rattling. If your cabs have 3015LF's in them I am sure you will be satisfied
3015's non-LF on purpose (Barefaced approach on this specific subject).
I am limited by power (and not by Xmax) up to 750W sinewave, worst freq. over 36 Hz per 2 cabs. In return, below 750W / 2 cabs I´ll enjoy 2 extra dB in efficinecy in low freqs (the 2.4 dB advantage averaged on the full range means nothing to me).
Different goal, different optimization... but not far. I wanna hear it soon !!!
I am limited by power (and not by Xmax) up to 750W sinewave, worst freq. over 36 Hz per 2 cabs. In return, below 750W / 2 cabs I´ll enjoy 2 extra dB in efficinecy in low freqs (the 2.4 dB advantage averaged on the full range means nothing to me).
Different goal, different optimization... but not far. I wanna hear it soon !!!
BurningSkies
CRAZY BALDHEAD
- Feb 20, 2005
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- Endorsing artist: Dingwall Guitars
Thank you
Yes, I tried it outside the box, too. I disconnected it and tapped the cone and you can hear the rattle in the back of the speaker. Definitely something not right back there.
So I have packaged it up to go back to the supplier.
From the little I heard with the cab together I can't wait to get the replacement speaker. It sounded SO good, even with the odd rattling. If your cabs have 3015LF's in them I am sure you will be satisfied
Yep. Sounds like a bad driver. Bummer.
This doesn't sound right. For starters, the thermal limit of the 3015 is 450w, so two should be 900w if excursion isn't a factor. But I've played with the 3015 model in WinISD a fair amount. The only way I've found to avoid being excursion limited is to make cab volume small (less than 50l), which penalizes bass output and makes porting more difficult. What's your cab volume and tuning?
My goal was to get max. acoustic output at some 300...350W per cab. This is dictated by my choice of micro-amp.
With a medium-size box (85 effective liters if I remember properly) and proper tuning (I think it is 48 Hz), I am equally limited by Xmax at both 36 Hz and then at some 5x or 60 Hz at 325W. I am speaking by heart, but numbers are accurate to 5%.
This means that for a limited output from my micro-head, I can get more output at ALL frequencies than using the LF version. Without having excursion limitations at any freq using sine waves. Using the proper equalization (so that I limit LF content) I should be able to handle a lot more power.
I know thermal limit is 450W. And I know if normal music reaches 450W average (i.e.RMS using real bass signals) then probably peak power is some 2000....3000W, so the LF version is ideal for some 1000...1500W power amps per single cab. Too much for the non LF below 60 Hz, I admit it,
If you want it simpler, 2 non LF cabs (some 1010 cm3 of displacement) can generate slightly more low freq SPL than a single LF driver (846 cm3) keeping things the same (box tuning, volume per cab, and given lowest usable frequency). In fact I can generate 1.5dB more SPL. Not so bad. Of course, it cannot compare to a 151566, but I think a bit better than a 156 is usable.
However, my 2 non-LF cabs will reach this same SPL it with 5dB less ampl power, that is roughly 1/3 of the power. And at 4 ohms, not 8. That's very convenient for any rig that puts less than 1000W @ 4 ohms.
So yes, I am displacement limited with the non-LF version. But this is way better for a micro-head delivering "only" 300W per cab.
If you're interested I can go revisit my exact numbers, but I think you can reproduce a good tuning with these box volume that gives you the same result.
In Barefaced Alex used the same approach for more than half their line. For the same reasons, I guess.
I thought a long time about using the LF version or a Beyma 15P80Nd (in Spain it costs just 20% more than the 3015, in the USA happy customers are paying more than twice as much for it due to customs in both countries). The Beyma is 700W, 7.5mm Xmax, better build, and a bit heavier (datasheet is wrong about weight)
In this case I´d go for a serious PA power amp + preamp. Bi.amping. No problem with time alignment or crossovers or with protecting the mid / hi horn.
I did not do it in the end because it is too much equipment for small gigs where I plan to use just ONE cab. And when I calculated SPLs with 2 cabs... it would be simply brutal, and I guessed 129dB with lower weight and the possibility of a very small rig could be enough. I was on the verge of doing so. and then the LF (or 15P80ND) optimization would be the way to go.
There are so many people with 200, 300 or 500W amps at 4 ohms, and for them my solution beats a single or dual 15 based on the LF hands down. Even if it is "clearly displacement limited".
So different optimization, not right or wrong. And about calculations, I think they are right, and it is very simple to do a quick sanity check on them.
- Dec 18, 2000
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- greenboy designs: fEARful, bassic, dually, crazy88 etc
These figures are not correct. Anyway, the major divisio is that the 3015 non-LF is more suited to the traditional full range bass cab approach. Once you cross over at 800 hz or so though, to a dedicated mid driver, all assumptions about sensitivity are moot. In fact, in a ~85 liter box with a tuning of say 45-55 Hz, with a dedicated mid and crossover, many people will perceive the 3015LF version of that box to be louder / more sensitive than the 3015 in the same setup, due to the 3015LF's moderate midbass hump at frequencies the electric bass output has the most energy at.
Not trying to demote your plans; in fact I've sat on a 3015-based design for several years now to give some breathing room to others, and was going to finally introduce that plan when the bad news about neo prices began surfacing some time ago. Similarly, I sat on a 3012HO version I did more recently after nabbing a driver and playing around with it... the sensitivity gains there are a lot higher above the 3012HF if one is prepared to live without sub-100 Hz sensitivity and a nice fit for all-tube amplification.
Thanks for clarifying, parapentep70. 85 liters = 3 cubic feet, which is about the volume of a TL606; a popular (though not optimal) cab for the 3015. WinISD indicates that would be excursion limited to about 145w sine at 36hz, rising quickly to 450w @ 41hz, then dipping to 365w @ 74hz. That's a very usable cab, especially for a EADG player.
The 3015 plots as 1-2dB more sensitive than the 3015LF, but that's a baffle measurement. In properly designed cabs, the difference is slight, and of course, the LF kills under 100hz. I hoped Greenboy would chime in on this, but didn't expect that he'd beat me to posting.
IMO, valid reasons for choosing the 3015 over the 3015LF are; wanting a smaller cab, and running full-range. Tonal preference could be third reason, if you don't want much sub-100hz output.
With a 300w head, I think it'd be difficult to overpower your cab. I don't know if there's a sensitivity advantage, but you're probably getting all the volume you need out of a smaller box. I'm headed in a similar direction, I think.
The 3015 plots as 1-2dB more sensitive than the 3015LF, but that's a baffle measurement. In properly designed cabs, the difference is slight, and of course, the LF kills under 100hz. I hoped Greenboy would chime in on this, but didn't expect that he'd beat me to posting.
IMO, valid reasons for choosing the 3015 over the 3015LF are; wanting a smaller cab, and running full-range. Tonal preference could be third reason, if you don't want much sub-100hz output.
With a 300w head, I think it'd be difficult to overpower your cab. I don't know if there's a sensitivity advantage, but you're probably getting all the volume you need out of a smaller box. I'm headed in a similar direction, I think.
Oobly: I had a 3012LF that had a voice coil rub from the factory. On powering up and playing through it, there was a rasping sound for the first minute or two (until it heated up, I guess) and then it sounded fine. Out of the box, you could hear a rub when pressing down on the cone. I returned it to Eminence and they replaced it.
eddiemac, sounds like the same problem with my driver. I have sent it back and the store is sending a replacement to me on Wednesday when they get stock in.
It was most noticeable at low volume, and on particular frequencies. Jack Johnson's "Wasting Time" hit the right notes and it sounded... horrible. I love the bass on that track. Simple, but great.
When it was clear it was fantastic. Can't wait to get it running again!
It was most noticeable at low volume, and on particular frequencies. Jack Johnson's "Wasting Time" hit the right notes and it sounded... horrible. I love the bass on that track. Simple, but great.
When it was clear it was fantastic. Can't wait to get it running again!
Greenboy, you've got a lot of experience, I hear what you say, and I admit that Eminence published their data at different times, there could have been variations in processes, or measurement errors due to different set-ups. Even the way the freq. response plot is included in the datasheet is slightly different (blurred for the LF). Then I think it is very possible that this 2 dB advantage is reduced to 1 or less.
But this is not reflected in my sims, or looking at infinite baffle responses for anything above 50 Hz. I mean using Eminence datasheet responses or TS parameters provided by them.
Looking at Eminence's published cab designs focused on the bass guitar region, if you compare " KappaLite 3015LF Small Hi Pwr PA or Bass Guitar Cabinet" (3.2 Cubic Feet) to "KappaLite 3015 Med Vented Cabinet" (2.48 CuFt, smaller, worse in LF region), you can see that at 450W, the non-LF is as sensitive as the LF below 100 Hz, but above the "hump" you mention the non-LF is more sensitive. Some 1.5 dB at 200 Hz, increasing to 2.2 or so at 500 Hz. I do not trust data beyond this point (more favourable to non-LF) because responses ar based on TS parameters, not real responses.
I understand the non-LF is displacement limited at 450W, but it is slightly more difficult to reach these limits at 325W, specially with a box customized to avoid this limitation.
Looking at real responses in 3015 datasheets above 100 or 200Hz, where the box is less important, non-LF response at all freqs. seems to be higher than the 150 Hz hump you mention for the LF. And the LF has peaks and a big dip at 450 Hz (difference reaches 4 dB).
There is a 3rd way I looked at things: Combining datasheet response with box response optimally tuned for both drivers (BBpro can do it) and I got this consistent advantage, closer to datasheet responses than to just TS parameters.
I admit responses could have been measured under slightly different conditions, and that A/Bing loudspeakers in an anechoic chamber at same time with same set-up could reduce this difference. I really could trust you more than the last dB published by Eminence, because I understand these differences are the order of the possible measurement errors and you possibly A/Bed the 2 drivers comparing apples to apples.
I also think these differences make perfect sense: I assume both drivers use the same magnetic assembly, but the LF uses a longer coil with more turns. This (in addition to a different suspension) allows for increased displacement. But I think it comes at the cost of slightly lower efficiency (higher flux leakage and DC resistance) and higher inductance (noticeable in mid region). (Hoffman's Iron Law?)
I am using mids, but crossed over at 1200Hz (90º beaming, that's exactly my dispersion goal for mid-mids and above). I really like the response of the non-LF over the LF in this tricky region: Non LF has a 3dB boost @ 1400 Hz that does not help, but it is not bad.
But LF has a boost / dip reaching 8dB total centered around 1200 Hz. I presume there will be some awkward phase problems at this frequency. So yes, I think non-LF will help me in getting good tone, even if I use a mid / high horn similar to AudioKinesis. Of course, without a dedicated mid driver the non-LF is the only sensible choice (Barefaced).
I still think for a relatively low power my non LF approach is better, but I admit the difference could be smaller than 2dB because Eminence could well have errors about 1dB and I trusted their responses to the last dB.
And I want to be clear: I was always convinced that the LF + mids is MUCH better & louder if amplifier watts are not a limitation.
Finally I was wrong about Barefaced cabs: My point is valid when comparing 3012LF to 3012HFO or to 3015, but there is no model using 3015LF to compare. And Greenboy, you're right that 3015 efficiency advantages over LF are considerably smaller than 3012HFO over 3012LF.
I think the discussion has been interesting, I continue learning, thanks for responding.
But this is not reflected in my sims, or looking at infinite baffle responses for anything above 50 Hz. I mean using Eminence datasheet responses or TS parameters provided by them.
Looking at Eminence's published cab designs focused on the bass guitar region, if you compare " KappaLite 3015LF Small Hi Pwr PA or Bass Guitar Cabinet" (3.2 Cubic Feet) to "KappaLite 3015 Med Vented Cabinet" (2.48 CuFt, smaller, worse in LF region), you can see that at 450W, the non-LF is as sensitive as the LF below 100 Hz, but above the "hump" you mention the non-LF is more sensitive. Some 1.5 dB at 200 Hz, increasing to 2.2 or so at 500 Hz. I do not trust data beyond this point (more favourable to non-LF) because responses ar based on TS parameters, not real responses.
I understand the non-LF is displacement limited at 450W, but it is slightly more difficult to reach these limits at 325W, specially with a box customized to avoid this limitation.
Looking at real responses in 3015 datasheets above 100 or 200Hz, where the box is less important, non-LF response at all freqs. seems to be higher than the 150 Hz hump you mention for the LF. And the LF has peaks and a big dip at 450 Hz (difference reaches 4 dB).
There is a 3rd way I looked at things: Combining datasheet response with box response optimally tuned for both drivers (BBpro can do it) and I got this consistent advantage, closer to datasheet responses than to just TS parameters.
I admit responses could have been measured under slightly different conditions, and that A/Bing loudspeakers in an anechoic chamber at same time with same set-up could reduce this difference. I really could trust you more than the last dB published by Eminence, because I understand these differences are the order of the possible measurement errors and you possibly A/Bed the 2 drivers comparing apples to apples.
I also think these differences make perfect sense: I assume both drivers use the same magnetic assembly, but the LF uses a longer coil with more turns. This (in addition to a different suspension) allows for increased displacement. But I think it comes at the cost of slightly lower efficiency (higher flux leakage and DC resistance) and higher inductance (noticeable in mid region). (Hoffman's Iron Law?)
I am using mids, but crossed over at 1200Hz (90º beaming, that's exactly my dispersion goal for mid-mids and above). I really like the response of the non-LF over the LF in this tricky region: Non LF has a 3dB boost @ 1400 Hz that does not help, but it is not bad.
But LF has a boost / dip reaching 8dB total centered around 1200 Hz. I presume there will be some awkward phase problems at this frequency. So yes, I think non-LF will help me in getting good tone, even if I use a mid / high horn similar to AudioKinesis. Of course, without a dedicated mid driver the non-LF is the only sensible choice (Barefaced).
I still think for a relatively low power my non LF approach is better, but I admit the difference could be smaller than 2dB because Eminence could well have errors about 1dB and I trusted their responses to the last dB.
And I want to be clear: I was always convinced that the LF + mids is MUCH better & louder if amplifier watts are not a limitation.
Finally I was wrong about Barefaced cabs: My point is valid when comparing 3012LF to 3012HFO or to 3015, but there is no model using 3015LF to compare. And Greenboy, you're right that 3015 efficiency advantages over LF are considerably smaller than 3012HFO over 3012LF.
I think the discussion has been interesting, I continue learning, thanks for responding.
I had a new more detailed look at Barefaced Cab Specs. Yes, there is no single 15 cab to compare 3015 to 3015LF performance... but there are dual 15 cabs using both flavors.
In Alex's implementations, LF sensitivity is the same. Broadband sensitivity and Max SPL 1...2 dB higher with the non-LF. And (of course!) LF power handling / max LF SPL is the area where the LF shines.
Using the cab tuning chosen by Alex, deep low extension (I guess due to trade-offs in box volume) is slightly better using the NON-LF version.
It can be seen in the spec sheet looking at the low frequency points at -3, -6 and -10dB, as well as the "lowest note designed to reproduce".
I guess that I spent long time trying to optimize volumes for 3015 non-LF and Beyma, using less volume than fEarful. When I tried to get an optimum tuning for the LF using the same volume, the difference in LF sensitivity was higher than it could have been optimizing volume also for the LF (the way fEarful was designed). I think this is where your numbers and mine show the 1 dB discrepancy.
In Alex's implementations, LF sensitivity is the same. Broadband sensitivity and Max SPL 1...2 dB higher with the non-LF. And (of course!) LF power handling / max LF SPL is the area where the LF shines.
Using the cab tuning chosen by Alex, deep low extension (I guess due to trade-offs in box volume) is slightly better using the NON-LF version.
It can be seen in the spec sheet looking at the low frequency points at -3, -6 and -10dB, as well as the "lowest note designed to reproduce".
I guess that I spent long time trying to optimize volumes for 3015 non-LF and Beyma, using less volume than fEarful. When I tried to get an optimum tuning for the LF using the same volume, the difference in LF sensitivity was higher than it could have been optimizing volume also for the LF (the way fEarful was designed). I think this is where your numbers and mine show the 1 dB discrepancy.
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