Nope, from my best understanding (and I could be wrong), voice calls do not get transmitted as "data," which we would commonly apply the term bandwidth to, but as voice on a separate faction of the carriers' networks, using different cell site equipment. For example, this means on Verizon Wireless' network, it's carried over their CDMA network. Data, on the other hand, is carried over their EVDO network (EVolution-Data Only) which is entirely separate and unaffected by voice calls.
Likewise, SMS (text messages) are carried over special channels of those networks. That's why if you're at a big event with a lot of people, such as a sporting event, your calls and data may not go through - but your text messages might (there are other reasons, such as auto-retrying, but that's another point).
That's why I mentioned Voice over LTE (VoLTE), a future technology much like Voice over IP (VoIP) to carry voice conversations over the currently data-only LTE network. Then, the carriers could shutter their legacy 2G and 3G networks and rely solely on their LTE networks (except you, Sprint).
The term “bandwidth” just refers to the size of the “pipe” available for transmitting signals. And it’s been a while since voice calls were transmitted as analog signals. They use digital systems for everything but the “last mile” of the network. Everything goes over the same network links, though various signals are separated out logically through different headers attached to the data packets. Here’s an explanation of voice calls from Wikipedia:
As described above, most automated telephone exchanges now use digital switching rather than mechanical or analog switching. The trunks connecting the exchanges are also digital, called circuits or channels. However analog two-wire circuits are still used to connect the last mile from the exchange to the telephone in the home (also called the local loop). To carry a typical phone call from a calling party to a called party, the analog audio signal is digitized at an 8 kHz sample rate using 8-bit pulse code modulation (PCM). The call is then transmitted from one end to another via telephone exchanges. The call is switched using a call set up protocol (usually ISUP) between the telephone exchanges under an overall routing strategy.
The call is carried over the PSTN using a 64 kbit/s channel, originally designed by Bell Labs. The name given to this channel is Digital Signal 0 (DS0). The DS0 circuit is the basic granularity of circuit switching in a telephone exchange. A DS0 is also known as a timeslot because DS0s are aggregated in time-division multiplexing (TDM) equipment to form higher capacity communication links.
A Digital Signal 1 (DS1) circuit carries 24 DS0s on a North American or Japanese T-carrier (T1) line, or 32 DS0s (30 for calls plus two for framing and signaling) on an E-carrier (E1) line used in most other countries. In modern networks, the multiplexing function is moved as close to the end user as possible, usually into cabinets at the roadside in residential areas, or into large business premises.
These aggregated circuits are conveyed from the initial multiplexer to the exchange over a set of equipment collectively known as the access network. The access network and inter-exchange transport use synchronous optical transmission, for example, SONET and Synchronous Digital Hierarchy (SDH) technologies, although some parts still use the older PDH technology.
Within the access network, there are a number of reference points defined. Most of these are of interest mainly to ISDN but one – the V reference point – is of more general interest. This is the reference point between a primary multiplexer and an exchange. The protocols at this reference point were standardized in ETSI areas as the V5 interface.