Boston 5x7 Speaker Differences

[Boston Acoustics]

demonfire suggested that I post on the differences between our (5) lines of mobile speakers, SPZ, Pro, SL, SX, & S. Each group is unique in terms of the feature set as you go from the top of the line, SPZ down to S but features definitely migrate from one group to another. Here is a snapshot of each group -

SPZ

This is our best component speaker offering. To handle the 5x7 application there is an adapter plate included in the installation parts. The SPZ60 woofer is a direct bolt-in for Ford. This woofer has ~22mm of peak-to-peak excursion and the system will provide good bass support without subwoofers. The cones use long-strand carbon fiber to provide extreme stiffness yet low weight. The woofers also have RadialVent which is a patented technique for managing the airflow around the cast aluminum chassis to cool the magnet and TwinStage which secures both the aluminum chassis to the magnet and adds a slug of aluminum billet inside the 37mm voice-coil to cool it further. Both the woofer & tweeter magnets are neodymium which offer compact size + powerful field. SPZ also uses our best tweeter the hard anodized alloy1" M1 which uses a patented acoustical filter called AMD which is mounted to the front of the tweeter to tune out resonance. Lastly, the crossovers are 24dB/octave and have optimization for both component or coaxial mounting. SPZ contains everything we've learned over the last 25 years about high-end loudspeaker design & performance. The crossovers include tweeter protection as well.

Pro

Pro has most of the features of SPZ except for the woofer cone (plastic), less excursion / ~16mm P2P, and smaller crossovers with high quality parts and include tweeter protection. The same 5x7 plate that SPZ uses is supplied with Pro and it works in an identical fashion. As SPZ goes lower in bass output than Pro, some find that Pro will sound "punchier" and Pro woofers often get used in midbass applications. The large 37mm voice-coils give them great power handling so they do work very well in this application. Seeing dual Pro60's for SPL applications is pretty common with some of our dealers. It does have RadialVent, TwinStage, cast aluminum chassis, and all neodymium magnets + our 1" M2 alloy tweeter. The M2 uses a simplified AMD from the one used on SPZ. Pro basically provides ~75% of the performance that SPZ has for ~50% of the price. Pro offers great bang for the buck!

SL

There are 2 ways to implement a 5x7 with SL. The first is that you can use the SPZ/Pro 5x7 plate with the SL60 woofer and install it exactly the same. Or you can use the SL80 component plate which uses the same woofer & tweeter as the SL60 but already mounted on a 1-piece 5x7 plate. The crossover is less complex than the SL60 because all the mounting provisions are known. SL has TwinStage but the implementation is different. Whereas SPZ & Pro use a cast aluminum chassis for one part of TwinStage, SL has a stamped steel chassis. What we do is add a diecast aluminum heat sink around the magnet cup as well as the billet slug inside the 37mm voice-coil. Excursion is a little less than Pro but not dramatically so. Most feel that SL has near equivalent bass output. The tweeter is our best soft dome, the 1" S1, made from a proprietary material called Kortec. Kortec is basically a fine ballistic nylon with special treatment to maintain its shape. Even in the coaxial models, all SL tweeters can be replaced should they get damaged. Crossovers for the SL60 components have the same complexity as Pro but the grade of materials are lesser but do include tweeter protection. Straight mylar film caps are used whereas Pro uses a more expensive material. Magnets are all neodymium for the woofers & tweeters as well. SL provides ~75% of the performance Pro for a bit more than ~50% of the price.

SX

SX is quite similar to SL but there are also significant differences. 1st, TwinStage is not used. A large steel magnet cup is in place without the SL heat sink. Other than that, the magnet system & woofers overall used are identical to SL. Further, there is an SX60 component which is similar to the SL60 but simplified. It can also use the SPZ/Pro 5x7 mounting plate. There is also a true oval cone 5x7, the SX85. Neodymium magnets are used in all SX models. Firther, for tweeters the 3/4" S2 Kortec tweeter is in place. Other than the size, it is identical to the S1 Kortec used in SL. It has less output than the S1 but identical sound quality within its range of operation. Like SL, if you damage an SX coaxial tweeter it can be replaced. Crossovers are equivalent to SL across the range and include tweeter protection. SX provides ~75% of the performance SL for roughly ~50% of the price.

S

There is only one true Ford drop-in 5x7 model within the S range, the S85. I have seen installations however where the S60 component has been used. The S60 however does not fit the 5x7 plate we offer so a custom mounting baffle must be built. S is the most conventional of all the speakers we offer but there are special features there as well. The main one is the baffle the tweeter is in which has slots in it. These help tune out resonance and even response. It is similar to the AMD found in SPZ & Pro. The magnets used for the woofers are ferrite and much larger than the neodymium ones used from SX on up. The tweeters however use neoydymium. The tweeter is the 3/4" S3 soft dome. Crossovers are simplified versions of the ones used in SX. S provides ~75% of the performance SL for roughly ~75% of the price and are a great OEM upgrade starting point.

So, the above is the Boston speaker outline in a nutshell. There are definite performance benefits as you go up further in the line to SPZ but like anything, the incremental gain gets smaller as the price increases. As a rule of thumb I always recommend that you spend the most on your front speakers even to the point of foregoing the upgrade to the rears. In other word, leave the OEM ones in place and spend that part of your budget on better fronts. They will most likely not need to be upgraded down the road and you can concentrate on other areas of the vehicle.

Leif