Studios will not (minus movies studios) but they are near field mixing studios and that is an entirely different setup then in home. We should not be matching what they do because that is not really wise in our own rooms.
I guess there is no problem if people are sitting near field but in general the best in room bass response (fixing nulls, decay, flatter curve) is only obtained by removing the bass from the mains and properly placing multiple subwoofers around the room.
Anyways, that is a different discussion. You can have down to 30Hz with mains....What are you doing about music to 20Hz? 😉
I look forward to your measurements and I hope you get them imported into X-over pro because I have it too.
Audax PR170M0 mid and Morel MDT-37 tweeter.
Here is the combo (drivers and amp) in one of my cabinets (still tweaking the box and crossover):
An externally hosted image should be here but it was not working when we last tested it.
I like what the 15" JBL does. Had my concrete slab floor vibrating Sunday for the cabinet's first audition.
I built these because I wanted a set of speakers with big drivers, specifically the 15" JBLs at the time.
Thanks, I almost bought that Audax PR170M0 midrange but I went with the B&C and PHL brands instead.
Always liked the Morel tweeter with its decent sensitivity but I fell in love with ribbons 2 years ago.
I love your design! 😎
Always liked the Morel tweeter with its decent sensitivity but I fell in love with ribbons 2 years ago.
I love your design! 😎
This web page is over a year old and I need to update it, but if you want to waste some time... 🙂
Obviously, the mid has been updated after working with the Eminence mid and feeling I could do better.
Which exact drivers did you use for the mid and ribbon?
I'm thinking of doing a triple 12 inch woofer version of my basement blaster (semi -column design) based on similar considerations. Interestingly enough, I found that when a tall cabinet with multiple bass drivers is ported at the bottom the lower drivers have greater LF excursion near the BR tuning frequency which works to advantage if the upper woofer is crossed over to the mid/hf as part of a 2 1/2 way configuration (less doppler distortion).
Earl if you don't use a high pass on the subs then your approach is to reinforce the bottom octave?
I have been using a simple bass boost system for some time after advice from Rabbitz, just a single large coil in series with the bass driver and turning what ever system I have into a ( + .5 ) system.
I have found this to be much better sounding than a simple 2-way, shouldn't sound as good as it does for the low cost involved.
I have been using a simple bass boost system for some time after advice from Rabbitz, just a single large coil in series with the bass driver and turning what ever system I have into a ( + .5 ) system.
I have found this to be much better sounding than a simple 2-way, shouldn't sound as good as it does for the low cost involved.
No, actually a majority recomend no high-pass.. but not for the same reasons.
For most it's usually a matter of perceived "purity", or a desire to not introduce yet another filter to the main speakers.
If the mains are sealed then there is a natural 12dB/oct hipass anyway. The bas are rolled off and need reinforcement to get to (or slightly above per Earl Geddes' recommendation) "unity".
Earl, would a very low tuning on the mains, for a slow rollof starting at 100Hz, also be a solution, to gain a little bit of efficiency?
I mean a BR box bith an unusually low tuning, and a "banana" curve.
The efficiency gain I am talking about is in the LF.
Here is an example (the orange curve, same box size for all curves).
What is the drawback of such a box compared to a closed box?
The idea would be to include the mains into the mix a little bit more than with a closed box (something like 3 more dB in the LF). Bad idea?
The efficiency gain I am talking about is in the LF.
Here is an example (the orange curve, same box size for all curves).
What is the drawback of such a box compared to a closed box?
The idea would be to include the mains into the mix a little bit more than with a closed box (something like 3 more dB in the LF). Bad idea?
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Majority as in who? Linkwitz, Harman people? All ported main speakers have to have a filter in them anyways so only sealed ones have truely natural rolloffs to protect that audiophile "purity"
No not a "bad" idea at all. BUT, if you look at the RMS cone displacement for a random signal (going well below cutoff) and compare it between the "low tuned" ported and the closed, you will likely find that the ported is something like twice as large. Yes, you get more output, but you also get more excursion - they go hand in hand - always. When operating a woofer over as large a bandwidth as I do, its a good idea to keep the excursion down. If you feel that you have "excursion to burn", then go for it! But if you can see the cone move then I suspect that the excursion is too high.
Users.
I believe Earl was talking about an *active* High-pass filter to attenuate the lower freq. response of the main speakers.
Users generally prefer running the loudspeakers full-range with no low-freq. attenuation.
As for Manufacturers.. I haven't seen much emphasis one way or the other. With most sub-woofers it's simply an option for the user (i.e. use the high-pass function or not).
Go it, thanks.
If maximizing bass response in room is a goal then people should have a HP filter their mains and use better designed subs placed properly around the room.
I have never seen a main speaker that does bass (20Hz to 70Hz) like a well designed subs (Ie..JL stuff) and I have never seen a case where the maximum response position is with the main speakers in room. Location is key and you can not do that when your bass is attached to your mains.
If maximizing bass response in room is a goal then people should have a HP filter their mains and use better designed subs placed properly around the room.
I have never seen a main speaker that does bass (20Hz to 70Hz) like a well designed subs (Ie..JL stuff) and I have never seen a case where the maximum response position is with the main speakers in room. Location is key and you can not do that when your bass is attached to your mains.
I was thinking of using a HP just under that low tuning frequency to prevent overexcursion.
In that case the excursion always remains lower than the sealed box.
Here is an example : magnitude and then excursion at 300W
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I attenuate LF Out of band information with a large series polypropylene capacitance at the input to the ported Iron Law Breakers (tuned to about 30hz). As a side bonus, it interacts with other xover elements and the speaker's natural ported upper impedance peak to neutralize that peak at the cabinet terminals and gain another couple dB of output in the half octave centered around that frequency. when I write 'neutralize', I mean the peak is gone since the impedance at the Iron lawbreaker terminals is 18 Ohms +/-20% from 40 hz to over 200hz without any Zobel type networks. The impedance drops to a minimum of 12 ohms around 31hz before rising below due to the series input C. A very friendly LF load for my DC Coupled OTL.
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