Opinion of the Court his evidence before the grand jury. "The persona fice involved is a part of the necessary contribu the individual to the welfare of the public." United States, 250 U. S. 273, 281. See also Gar Torre, 259 F. 2d 545, 549. And while the dur be "onerous" at times, it is "necessary to the istration of justice." Blair v. United States, si 281.8 The compulsion exerted by a grand jury su differs from the seizure effected by an arrest an investigative "stop" in more than civic ob For, as Judge Friendly wrote for the Court of for the Second Circuit: "The latter is abrupt, is effected with forc threat of it and often in demeaning circun and, in the case of arrest, results in a re volving social stigma. A subpoena is se the same manner as other legal process; it no stigma whatever; if the time for appearan convenient, this can generally be altered; a mains at all times under the control and sup of a court." United States v. Doe (Schwo F. 2d, at 898. Thus, the Court of Appeals for the Seventh correctly recognized in a case subsequent to now before us, that a "grand jury subpoena to not that kind of governmental intrusion on against which the Fourth Amendment affords p once the Fifth Amendment is satisfied." United States, 452 F. 2d 616, 620; cf. United Weinberg, 439 F. 2d 743, 748-749. * The obligation to appear is no different for a perso himself be the subject of the grand jury inquiry. See U v. Doe (Schwartz), 457 F. 2d, at 898; United States 348 F. 2d 204, 207-208. This case is thus quite different from Davis v. M sippi, supra, on which the Court of Appeals prim relied. For in Davis it was the initial seizure-the less dragnet detention that violated the Fourth Fourteenth Amendments, not the taking of the fi prints. We noted that "[i]nvestigatory seizures subject unlimited numbers of innocent persons te harassment and ignominy incident to involuntary d tion," 394 U. S., at 726, and we left open the que whether, consistently with the Fourth and Fourt Amendments, narrowly circumscribed procedures be developed for obtaining fingerprints from people there was no probable cause to arrest them. I 728. Davis is plainly inapposite to a case wher initial restraint does not itself infringe the F Amendment. 9 This is not to say that a grand jury subpoena is talisman that dissolves all constitutional protec The grand jury cannot require a witness to t against himself. It cannot require the production person of private books and records that would inc nate him. See Boyd v. United States, 116 U. S. 633-635.10 The Fourth Amendment provides prote against a grand jury subpoena duces tecum too swe in its terms "to be regarded as reasonable." Ho Judge Weinfeld correctly characterized Davis as "but a application of the principle that the Fourth Amendment a to all searches and seizures of the person no matter what the or duration. It held that in the circumstances there present detention for the sole purpose of fingerprinting was in violat the Fourth Amendment ban against unreasonable search and se Thom v. New York Stock Exchange, 306 F. Supp. 1002, 1007 note omitted). See also Allen v. Cupp, 426 F. 2d 756, 760. 10 While Boyd was concerned with a motion to produce in at a forfeiture trial, the Court treated it as the equivalent subpoena duces tecum, and Hale v. Henkel, 201 U. S. 43, 76, a Boyd in the context of a grand jury subpoena. Opinion of the Court Henkel, 201 U. S. 43, 76; cf. Oklahoma Press Pub Co. v. Walling, 327 U. S. 186, 208, 217. And last in the context of a First Amendment claim, w cated that the Constitution could not tolerate the formation of the grand jury into an instrument pression: "Official harassment of the press unde not for purposes of law enforcement but to dis reporter's relationship with his news sources woul no justification. Grand juries are subject to control and subppenas to motions to quash. We expect courts will forget that grand juries must within the limits of the First Amendment as the Fifth." Branzburg v. Hayes, 408 U. S., at 7 See also, id., at 710 (POWELL, J., concurring). But we are here faced with no such constit infirmities in the subpoena to appear before the jury or in the order to make the voice recordings. is, as we have said, no valid Fifth Amendmen There was no order to produce private books and and no sweeping subpoena duces tecum. And Branzburg be extended beyond its First Ame moorings and tied to a more generalized due pro cept, there is still no indication in this case of of harassment that was of concern there. The Court of Appeals found critical significan fact that the grand jury had summoned appro 20 witnesses to furnish voice exemplars." Wetl fact is basically irrelevant to the constitution here. The grand jury may have been attem 11 As noted supra, at 11, there is no valid comparis the detentions of the 24 youths in Davis, and the subpoenas of the witnesses here. While the dragnet by the police did constitute substantial intrusions into and Fourteenth Amendment rights of each of the youth no person has a justifiable expectation of immunity fro jury subpoena. 72 410 U. S. ma Press Publishing al significance in the lid comparison between 1 Opinion of the Court identify a number of voices on the tapes in evidenc it might have summoned the 20 witnesses in an effo identify one voice. But whatever the case, "[a] g jury's investigation is not fully carried out until e available clue has been run down and all witnesses amined in every proper way to find if a crime has committed..." United States v. Stone, 429 F. 2d 140. See also Wood v. Georgia, 370 U. S. 375, 392. the Court recalled last Term, "Because its task inquire into the existence of possible criminal con and to return only well-founded indictments, its inv gative powers are necessarily broad." Branzbur Hayes, supra, at 688.12 The grand jury may well it desirable to call numerous witnesses in the co of an investigation. It does not follow that each ness may resist a subpoena on the ground that too n witnesses have been called. Neither the order to Dio to appear nor the order to make a voice recording rendered unreasonable by the fact that many ot were subjected to the same compulsion. But the conclusion that Dionisio's compulsory app ance before the grand jury was not an unreason "seizure" is the answer to only the first part of the Fo Amendment inquiry here. Dionisio argues that grand jury's subsequent directive to make the recording was itself an infringement of his ri 12 "[The grand jury) is a grand inquest, a body with p of investigation and inquisition, the scope of whose inquiries to be limited narrowly by questions of propriety or forecas the probable result of the investigation, or by doubts whether particular individual will be found properly subject to an ac tion of crime. As has been said before, the identity of the offe and the precise nature of the offense, if there be one, normall developed at the conclusion of the grand jury's labors, not a beginning. Hendricks v. United States, 223 U. S. 178, 184." BE United States, 250 U. S., at 282. Opinion of the Court 41 under the Fourth Amendment. We cannot accep argument. In Katz v. United States, supra, we said tha Fourth Amendment provides no protection for w person knowingly exposes to the public, even in h home or office..." 389 U. S., at 351. The pl characteristics of a person's voice, its tone and man opposed to the content of a specific conversatio constantly exposed to the public. Like a man's characteristics, or handwriting, his voice is repe produced for others to hear. No person can have sonable expectation that others will not know the of his voice, any more than he can reasonably that his face will be a mystery to the world. Court of Appeals for the Second Circuit stated "Except for the rare recluse who chooses to life in complete solitude, in our daily lives stantly speak and write, and while the cor a communication is entitled to Fourth Ame protection the underlying identifying teristics the constant factor throughout bot and private communications are open fo see or hear. There is no basis for constr wall of privacy against the grand jury wh not exist in casual contacts with strangers. no intrusion into an individual's privacy res compelled execution of handwriting or voi plars; nothing is being exposed to the gr that has not previously been exposed to t at large." United States v. Doe (Schwa F. 2d, at 898-899. The required disclosure of a person's voic immeasurably further removed from the Fourth ment protection than was the intrusion into effected by the blood extraction in Schmerb |