# Experienced assistance



## Guest (Jul 8, 2008)

I am in the process of building new speaker cabinets. I have the new drivers and have been working with several different speaker design software programs, but I just don't have the experience to know which way to proceed. can someone direct me to someone who can take my driver's parameters and my goals, and come up with the correct design?

Thanks, Kerry


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## avaserfi (Jul 5, 2007)

There are members here who will be able to help you. If you post a list of intended drivers and their parameters as well as goal you will be helped. Information about the equipment you are using as well as your room would be helpful.


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## Mike P. (Apr 6, 2007)

Thread moved to DIY Speakers.


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## Guest (Jul 8, 2008)

My system will be used mainly for watching concert videos. the drivers are as follows:
ultra high frequency - radian 465pb 1" horn driver mounted on a 60 x 40 degree horn lense.
high frequency - radian 850pb 2" horn driver mounted to a 60 x 40 degree horn lense.
midrange - 2 x BMS - 8N215 - 8" drivers. (powered by 1200 watts @ 4 ohms)
upper bass - 2 x 18 sound - 15LW1401 - 15" drivers. (powered by 4000 watts @ 4 ohms)
sub - 2 x Aura - NRT18-8 - 18" drivers (powered by 4000 watts @ 4 ohms)

As you can see, this system is being designed for extreme sound levels. My goal is to tune the system as to where it will need little or no equalization. My present system is running on a little more than 1/2 this amount of power with lesser drivers and I generally do not use any tone controls or equalization other than balancing the drivers with a 4-way electronic crossover, (the horn drivers are and will be crossed over passively between each other and are powered by 600 watts @ 4 ohms).
The hardest part for me is to know where to tune the 15" drivers cabinet section. I presently crossover between the 15" and the 18" drivers at 65 hz, which seems to work ok, but I don't think the 15's are tuned right. I am switching from the present "Eminence" omega pro 15" to the 18 sounds because they sound cleaner to me. What internal cabinet volume and what tuning frequency would work best for the 15's? With my "BassBox 6 pro, I set my box volume at 3.649 cubic feet per driver tuned to 57hz. Should I tune it lower to blend with the 18's better? (The 15" drivers plot shows that they will stay within Xmax down to 65hz at a full 4000 watts.).
any advice on volumes, tuning and crossover frequencies for the 8's, 15's and 18's would be deeply appreciated.
The driver specs follow:
8" BMS-APPLICATION Low-Middle
Nominal impedance Ohm 8
Power handling AES noise W 200
Sensitivity ( 1W/1m ) dB 96
Frequency response Hz 80 - 3000
Voive coil diameter mm 52 (2”)
Voice coil material Al
Voice coil winding depth mm 15
Magnet gap depth mm 7
Basket Cast Aluminium
Effect. diaphragm diameter D mm 168
THILE – SMALL PARAMETERS
Resonance frequency Fs Hz 87.7
DC resistance Re Ohm 5.40
Mechanical Q factor Qms 4.34
Electrical Q factor Qes 0.32
Total Quality factor Qts 0.30
Equivalent volume Vas L 11.04
Moving mass Mms kg 0.0206
Mechanical compl. Cms mm/N 0.16
BL factor BL Tesla/m 13.80
Effective piston area Sd m2 0.0222
Max. linear excursion Xmax mm 4
Voice coil inductance Le1k μH 0.20 (4 Ohm)
Le10k μH 0.12 (4 Ohm)

15" 18 sound-
Impedence - 8 ohms
continous pink noise - 1000 watts
sensitivity - 98 db
Fs - 42hz
Re - 5 ohms
Sd - .090 sq. mt.
Qms - 5,36
Qes - .28
Qts - .27
Vas - 131 lt.
Mms - 125 gr.
Bl - 24.2
Xmax - 9mm
Le (1khz) - 2.15mh

18" Aura-
• NO Stray Magnetic Fields
Impedance
Frequency Response (1W, 1m)
Distortion (1W, 1m)
Nominal Diameter (Ø) . . . . . . . . . . . 18 inches (464 x 464 mm)
Nominal Impedance (Z) . . . . . . . . . . 8 Ohms
Sensitivity, 1W/1m (E) . . . . . . . . . . . 96 dB
Power Capacity, RMS (Pe) . . . . . . . . 800 W
Power Capacity, Peak . . . . . . . . . . . 3200 W
Frequency Range (-10dB) . . . . . . . . Fo - 2 kHz
Minimum Impedance . . . . . . . . . . . . 8 Ohms
Voice Coil Diameter (Ø) . . . . . . . . . . 99.1 mm
Voice Coil Winding Length (h) . . . . . 25 mm
Voice Coil Number of Layers  . . . . 1
Voice Coil Former Material . . . . . . . . Fiberglass
Voice Coil Wire Composition . . . . . . Edgewound aluminum ribbon
Magnetic Material . . . . . . . . . . . . . . Neodymium radial
Stray Flux Shielding . . . . . . . . . . . . . Inherent
Magnetic Gap Depth (He) . . . . . . . . 50 mm
Cone Material . . . . . . . . . . . . . . . . . Paper/fiberglass/epoxy
Surround Material . . . . . . . . . . . . . . Polyester weave
Polarity, Outward Motion . . . . . . . . . Po s i t i ve voltage on (+) term i n a l
Net Weight . . . . . . . . . . . . . . . . . . . . 13.5 kg (29.6 lb)
Thiele / Small Parameters
Resonant Frequency (Fo) - Fs . . . . . 25 Hertz
Voice Coil DC Resistance - Re . . . . . 5.6 Ohms
Total Q - Qts . . . . . . . . . . . . . . . . . . 0.26
Mechanical Q - Qms . . . . . . . . . . . . 4.4
Electrical Q - Qes . . . . . . . . . . . . . . 0.28
Equivalent Volume of Air - Vas . . . . . 475 L
Radiating Piston Area - Sd . . . . . . . . 0.124 m2
Linear Excursion - Xmax . . . . . . . . . 18 mm
Electrical / Mechanical Parameters
Flux Density x Length - BL . . . . . . . . 24.5 Tesla-meters
Compliance - Cms . . . . . . . . . . . . . . 218 μm/N
Total Mass - Mms . . . . . . . . . . . . . . 186 grams

Thanks for your time,
Kerry:scratchhead:


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## JCD (Apr 20, 2006)

ultra high frequency - radian 465pb 1" horn 
high frequency - radian 850pb 2" horn driver 
midrange - 2 x BMS - 8N215 - 8" drivers.
upper bass - 2 x 18 sound - 15LW1401 - 15" drivers.
sub - 2 x Aura - NRT18-8 - 18" drivers 


Aya carumba, those look to be some heavy duty drivers!

As for the tuning, I think you have enough overlap if frequency response that I would be very conservative in the box tuning. Whatever came out with the flattest modeled response is what I'd probably try. In fact, I'd seriously consider removing some of those drivers from the overall system, in particular the two horns you have for the upper octaves. I would think just one of those would be plenty down to the 8" or maybe even the 15" drivers. My personal prejudice is to have as few crossover points as possible. 

All of which is probably not that helpful, but I'd stick with the more conservative tuning frequencies given the overlap you've got and the (I'm assuming) quality drivers you're using.

Also, I'd LOVE to see some pictures.. I really know so little about horns, but man are they sexy.

JCD


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## Guest (Jul 9, 2008)

I've used systems with just 15's and horns for many years. 15's can do quite well in the lower frequencies as long as you don't need extreme volumes (like I do), but there has always been a void in midrange quality between the 15 and the horn. I had some "Altec voice of the theater" speakers that did pretty well due to the very light 15, but they can't take much power. Adding a mid did wonders. As for the two horns, The 2" driver I am using is the best driver I have found for smooth extended frequency response (and I have tested many), but it still dont have that shimmer that some lower power tweeters have. I tested Many tweeters (about $3000 worth) and found the "Aurum Cantus" ribbons to be fabulous beyond words "BUT" they couldn't hang. When playing my favorite tweeter test song, Fleetwood Mac, Dreams, the symbol crash would flatten the folds right out of the ribbon, even with 4 of them on each side. The best runner up I have found is the BMS 4540 ND 1" driver, which does admirable and keeps up with the volume with no problem, but I am still going to test the radian 1", I believe it might do better yet. I will do a test soon, but there is no rush since it will not affect my enclosure design. 
The system sounds much better as a 5 way system than it did with less. I would really like to have someone that has a lot of experience to plot this system out and show me their findings.
I am using a 24db per octave electronic crossover.
I can't afford to build and test a bunch of different cabinets to find the best combination.
Thanks, Kerry


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## JCD (Apr 20, 2006)

Hey, looks like you did your due diligence!

Hopefully someone can chime in and give you some help. I can only give you "theoretical" help at this point in my "career".

JCD


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