A larger, but relatively flat, set of speakers which are permanently connected to the central amplifier unit. Each speaker unit has two drivers. They might just as well have built it as a single speaker, since you get virtually no stereo separation, but this is common to most portable speakers. Sound quality is good, achieving decent volume and reasonable bass. Tonal balance is good to very good. Level of sound output is relatively low compared to some other high-end speakers.

This unit is a robust, heavier assembly with what appear to be three separate drivers. Each driver is protected by a metal grill, so it is very resistant to damage. There is a thumbwheel volume control and a sliding on-off switch on the front. The base is covered by a rubber pad so the unit stays where you put it. There are two separate battery compartments on the back, each taking two AA batteries. There is also a jack on the back that allows you to power it from a 9 VDC source. It does not come with a power source of this type, but they are readily available from Radio Shack or other sources. The sound quality is rather muted, without the clarity of the Panasonic SPT70 or the more expensive speakers. Bass performance is satisfactory, but nothing exceptional. Like virtually every other speaker here, a separate headphone amplifier greatly improves the sound of this speaker unit. Due to its weight and size, I prefer to use this unit in a fixed location, rather then travelling with it. It does come with a very nice carry case in soft fabric with Velcro closures.

This is a rather unusual design, being shaped rather like a hip flask of about a pint capacity. The two speaker drivers are protected by a sliding cover that doubles as a stand to elevate the speakers slightly. The cover also turns the electronics off when it is closed. I understand that the amplifier is a Class D (digital) amp circuit, which may explain the above-average battery life I've experienced. This unit is only a little larger than the Sony SRS-T33, but sounds far superior.

I find that these work amazingly well when I am doing a presentation for a group and I need to play audio from my laptop. These things will fill a good-sized room with surprisingly high-quality sound.

This unit is a real "sleeper". It's a small folding speaker that feels pretty cheap, but sounds very good. The speakers are hinged to the sides and lock in the backwards position to create a light-weight, near-cubic block. There's a sliding on-off switch, but no volume adjustment. The audio cable is integrated and folds into a slot on the back of the unit.

This is a rather specialized speaker system. It is capable of great stereo separation, since the speaker units connect to the main amplifier unit with cords and can be placed just about anywhere within reason. The speakers have spring clamps on the sides that allow them to be "attached" to the amplifier or clamped on the sides of a laptop computer display. The sound is very good, but the complexity of putting the whole thing together can be a bit overwhelming. Once you set it up somewhere, you probably don't want to pack it up again until you have to.

To be honest, I hardly ever use these anymore, unless I'm out on my deck.

These are "clamshell" speakers intended for limited volume and fidelity. Radio Shack has an almost identical set of speakers with an internal amplifier, but I wouldn't bother with them. These un-amplified units sound almost as good (which isn't very) and, if you want to amplify them a bit more, you are a lot better off to use a separate headphone amplifier of some sort. The sound from these can best be described as "marginal". Volume is low and fidelity is severely limited. About the only thing positive I can say about them is that they appear to be durable and that they come with a little pouch for a carrying case. Even though they're not amplified, they're still about the same size as the Panasonic speakers (above).

UPDATE: OK, I just found a decent use for these speakers. The rear-mounted speaker on my Magellan GPS is OK, but it faces the windshield or the A/C vent and a lot of the sound gets lost. If I plug this speaker into the headphone jack and position them correctly to face me, the set-up works very well and I get good volume with improved clarity. I especially like using these folding speakers because they don't use batteries and they are so low in cost that I don't really care if they disappear.

You can't get these anymore, but it was (sort of) an OK idea. There are two very small speaker drivers in a single plastic enclosure. The base of the enclosure is molded to have a 1/8" mini-headphone plug extending from it for direct insertion into the headphone or speaker jack of a portable unit. There is no internal amplifier. Like the other Radio Shack unit, this is probably best saved for emergency use. It performs at some level, and is superior to the small internal speakers in battery-powered, handheld LCD TVs, but that's not saying much.

What a joke! This generation of Sonic Impact speakers sounds horrible. I agree with many other reviewers that you can position these near corners and other cabinets to get better bass and tonal balance, but why bother? You can get speakers that are just as small (or smaller) that sound infinitely better no matter where you put them. Besides, I never got to experiment with these for more than a couple weeks because the amplifier unit just stopped working. No amount of fiddling would get it to work again.

UPDATE: I've given this some additional thought and decided that I may not have properly conveyed how awful these are. These are absolutely terrible speakers.

It's worth looking at this unit just because it's shaped like a hot dog. If your TS33 doesn't sound very good, at least you can laugh at it. Just kidding...these actually work OK and are useful, but they're not worth the $$$ Sony wanted for them. (I think that they're obsolete now.) These cute little units have a built-in amplifier and a compartment to store the integrated audio cable, as well as a stand that folds out the back. Due to their shape, they're almost indestructible...if you squeeze them or try to crush them, they shoot out of your grasp or out of danger in your bag. They don't have a volume control and they can only be powered by batteries.

These folding speakers are very similar to the later Sony Model T57, both in appearance and sound, but many users seem to prefer the sound of the T55 to its successor. Like the Panasonic RS-SPT70, the speaker modules on the T55 fold back around the amplifier/battery holder section. There is no volume control, though there is a connection for an external DC power supply. The T55 does not come with a case. The T55 is usually more expensive than the SPT70, often nearly twice the price, but it does not sound any better. While it is a decent performer, it falls short of the clarity of the SPT70. It also does not begin to produce the bass that the more expensive InMotion and On Tour units can. If you have access to these speakers or find a pair for sale cheap, go ahead and pick them up and use them. But the SPT70 is usually a better buy.