Actually no. I just finished reading his book, Get Better Sound.
Seems as if he has lots of experience with many hundreds of system
he has set up.
Jim Smith often prefers subs with a ventilated pole piece, but when it comes to enclosure type, he actually recommends ported (vented) subs over sealed subs for several reasons:
1. Efficiency: Ported subs are generally more efficient than sealed subs, meaning they can produce more bass with the same amount of power.
2. Low-frequency extension: Ported subs can often extend lower in frequency than sealed subs, especially in the 20-30 Hz range.
3. Dynamic range: Ported subs can handle more dynamic range and produce more SPL (sound pressure level) than sealed subs.
However, sealed subs have their own advantages, such as:
- Tighter, more controlled bass: Sealed subs tend to have a more accurate, "tighter" bass response.
- Smaller size: Sealed subs are often smaller and more compact than ported subs.
Ultimately, the choice between sealed and ported subs depends on the specific application, room size, and personal preference. Jim Smith's preference for ported subs is likely due to their ability to produce more bass and dynamic range, but sealed subs can still be a great option for certain situations.
1 - Correct, at the expense of a larger cabinet
2 - Incorrect. Below port tuning, a ported box is basically useless. Any driver in a sealed box has output down to below 0.01Hz, albeit SPL will be lower than the nominal passband.
3 - Yes, they can get louder, but only in the range where the port is helping out. At 100Hz, max.SPL will be equal.
Something that's been missed: for wider bandwidths, port resonances can become an issue as well. It takes very careful tuning to get rid of those effectively.
IMO, sealed cabinets are the correct choice for a domestic system: if you're pushing the audio equipment so loud that switching to ported makes the difference, then you're no longer listening to high fidelity. There'll be too much harmonic distortion, clipping, etc etc.
Sealed boxes get you more LF extension (once EQ'd), in a smaller box. If you need more output, use more of them.
As a live sound engineer, the mention of PA systems as some kind of reference amuses me. PA systems are designed with one thing in mind: output density. That is, the most output from the smallest space possible.
This is true from the small coffee shop gigs: they might use a pair of 8" or 10" speakers on stands, because they don't need/want a pair of 15"s taking up loads of room.
All the way up to the stadium concerts, where it's about logistics: if Brand X subwoofers would fill 3x trucks to do the job, and Brand Y would need 4x trucks, the tour management are going with Brand X. Easier load-in/out, less fuel used, less cabling, etc etc etc.
It's not about dry/tight/extended/whatever. Which thing is going to do the job, in the smallest space possible?
I'm also point out that, in a lot of venues, the LF reverb time will often turn the bass to mush. This is, I suppose, the opposite of "dry", but it could hardly be considered a good thing.
