The 1508he is best used as the bottom end of a full range enclosure. It has very high efficiency for superior output in the mid-bass and mid-range. However, for pure subwoofer applications, the 1508sps or 1508cu are better choices.
The 1208sps works well in sealed or vented enclosure designs, and its smooth, extended frequency response makes it an excellent mid-range performer. It is available in 4 and 8 Ohm versions.
Because the 1208sps???s low frequency output is limited, it should be used along with a subwoofer when response below 60 Hz is needed. The best application for the 1208sps is in compact enclosures and very high quality mid-bass/mid-range reproduction at high sound pressure levels.
The 15" drivers can work with crossover points as high as 2.0 kHz but work best below 1.5 kHz. The 12" drivers are usable to 3.5 kHz but perform best below 2.5 kHz.
ENCLOSURES
To assist with the growing interest in home-built enclosure designs, Peavey provides complete parameter data on these drivers as well as several recommended enclosures for each
Vents used in the examples require standard Schedule 40 PVC pipe for vent construction. The pipe should be dadoed tightly into the back of the baffle and glued firmly in place with high quality epoxy or high strength industrial grade hot glue. Rough up the outside of the pipe to improve the glue bond.
Be sure to account for the displacement of the vent, bracing, horn (if used) and woofer or your enclosure before building it, or it will be smaller than its intended volume. This can reduce bass output and mis-tune the enclosure.
Line the inside of the enclosure with polyester fiber batting such as quilt stuffing. The batting material should conform to California bedding fire codes. Attach the batting with spray adhesive or staples, and keep it away from the end of the vent tube where it could be pulled in by air flow. Handles, protective corners, cabinet covering, grille materials and crossovers are available through Peavey Accessories.
When building a bandpass enclosure, design a panel or door to be removable for access to the woofer. Use foam weather-strip to seal the panel along with enough screws and bracing to prevent leaks and buzzes. Fill the sealed volume loosely with polyester fiber, but leave the
enclosure together for optimum performance in any application.
PARAMETER DEFINITIONS
Znom: The nominal impedance of the driver in Ohms.
Revc: DC resistance of the driver in Ohms. Also known as Re.
Sd: The functional radiating surface area of the cone assembly, in meters2.
BL: Efficiency of the voice coil and magnet system in Telsa Meters.
Fo: Also known as Fs, the free air resonance of the driver.
Vas: Volume of air having the same
compliance (springiness) as the driver???s suspension.
Cms: Restorative force of the driver???s suspension in micrometers/Newton.
Mms: The total mass of the moving
parts of the loudspeaker, including the air load, in grams.
Qms: Resonance characteristics of the mechanical factors of the loudspeaker.
Qes: Resonance characteristics of electrical factors of the loudspeaker.
SUGGESTED ENCLOSURES
For those who want to build their own enclosures, but don???t want to go through the design process using driver parameters, we provide the following optimized designs:
FOR 1508-4/8sps:
Sealed enclosure
May be preferred for stage monitors to control boominess and low frequency feedback on stage. F3 is 73 Hz.
Small vented enclosure
Excellent performance for compact, general purpose use. Warm mid-bass response. F3 is 51 Hz.
Medium vented enclosure
Terrific compromise of bass performance and enclosure size. Warm mid-bass response. F3 is 45 Hz.
Large vented enclosure
Big box, big bass! Great response as a subwoofer or the bottom end of a large multi-way enclosure design. F3 is 41 Hz.
Single reflex bandpass enclosure
Special enclosure design that uses the enclosure as an acoustic filter for shaped response. Great choice for a compact subwoofer system. Response is 48 Hz ??? 138 Hz.
FOR 1508-8cu:
Small vented enclosure
An incredibly small enclosure with outstanding bass performance for its size. F3 is 53 Hz.
Medium vented enclosure
Small box with powerful bass and predictable, flat response down to an F3 of 45 Hz.
Large vented enclosure
Strong, flat response with bass extension to an F3 of 41 Hz. Deep, predictable bass quality for great subwoofer and multi-way system performance.
FOR 1508-8he:
Small vented enclosure
Small box, big voice. Very high efficiency and good bass performance in a small enclosure. F3 is 60 Hz.
Medium vented enclosure
Super-high efficiency in a popular enclosure size. F3 is 55 Hz. Great choice for use in a full-range system.
Large vented enclosure
Big and loud! Super efficiency and strong bass performance to an F3 of 50 Hz. However, for subwoofer-only use the sps and cu versions which are better performers.
FOR 1208-4/8sps:
Sealed enclosure
Excellent choice for a dedicated mid-bass/mid-range in a multiway system, or stage monitor. F3 is 105 Hz.
Small vented enclosure
Very small system with excellent voice range perforance. Great choice as the mid-range of a sub/satellite system. F3 is 79 Hz. Also good for use in a stage monitor.
Large vented enclosure
Still not all that large, with very usable bass response. Great for a compact, 2-way box. F3 is 61 Hz.
model. This information and much more can be found at www.peavey.com.
Enclosures should be built of best-quality 3/4" marine or other high grade plywood. Particle board and MDF enclosures can be easily damaged and are not recommended for portable applications, but may be acceptable for permanent installation. If construction plywood must be used, inspect each sheet thoroughly and use at least BC grade.
Use a quality wood glue, fit joints tightly, and add internal bracing to stiffen the panels of the enclosure. Look at commercially designed enclosures for ideas on good brace placement. Use wood screws or a pneumatic nailer to assemble the enclosure during gluing, to maximize joint strength.
Strength of the completed enclosure has a great effect on the bass performance of the finished system. Box panels that aren???t stiff enough will vibrate ??? cancelling bass produced by the woofer, and creating undesired sounds of their own. If your box vibrates or you don???t think the box panels are stiff enough, add more bracing.
vented volume empty. Place the magnet of the woofer in the vented side for improved cooling.
Peavey does not supply hardware required for the manufacturing of flying systems, and recommends that builders should not suspend or fly any enclosure not certified for such applications.
These instructions are a general guideline for design. Proper construction techniques, good planning and common sense will result in a reliable, high quality, high performance system.
Peavey in no way accepts liability for any damage, accidents or injury that may result from construction or use of enclosures using this information.
Features and specifications are subject to change without notice.
PARAMETERS
Thiele-Small parameters for Black Widow?? 1208 and 1508 drivers follow. This data is for use in designing enclosures. Numerous software packages are available that use this data to simulate the response of the driver and
Qts: Resonance characteristics of the
electrical and mechanical factors combined together.
Xmax: Distance the cone can move in
one direction before the coil begins to leave the magnetic gap.
Le: Inductance of the voice coil in millihenries.
SPL: Typical sound pressure level at 1 Watt, 1 meter.
no: Electrical-to-acoustical conversion efficiency in percent.
Vd: Air displacement of the driver
from negative Xmax to positive Xmax, in milliliters.
Pmax: Maximum continuous program power in Watts.
Disp: Volume displaced by the driver inside the cabinet when mounted on its rear flange, in inches3.
Kevlar?? is a registered trademark of DuPont.
Rubatex?? is a registered trademark of Rubatex Corporation.
Nomex?? is a registered trademark of DuPont.
