McCreary was convicted by a jury on charges of assault and battery by means of a dangerous weapon (a shod foot), G. L. c. 265, § 15A, and assault by means of a dangerous weapon (a knife), G. L. c. 265, § 15B. The sole issue on appeal concerns the exclusion of certain testimony on cross-examination of the victim’s wife. We affirm the convictions.
*691We summarize the evidence and rulings pertinent to the issue. The victim, one Malone, separated from his wife in October, 1979. The separation was caused in part by her relationship with McCreary. In November, 1979, Mc-Creary began living with Malone’s wife, but she also continued to see her husband. On February 8, 1980, Malone went to the marital home at his wife’s invitation under the belief that McCreary would not be there. Shortly after he arrived, however, McCreary returned. At some point thereafter, McCreary, in the presence of Malone’s wife, struck Malone, knocked him down, and kicked him repeatedly and savagely about the chest with his booted foot. Then, while Malone lay semi-conscious on the floor, the defendant took a knife from the kitchen and pointed it at Malone, telling him, “I could kill you.” As a result of the heating, Malone required surgery and was hospitalized for two weeks with serious injuries. Malone denied that he had been armed at the time of the encounter or that he had done anything to provoke the attack. He admitted in cross-examination that prior to this incident, he had threatened his wife with physical harm, and that he and McCreary had exchanged words regarding his wife. However, he denied that he had ever made threats against McCreary.
McCreary took the stand and testified in detail about several prior incidents in which Malone had threatened him, including one incident in which Malone had said he would “break [my] legs . . . [and] blow [me] away with [his] shotgun.” McCreary claimed that the assaults were acts of self-defense precipitated by Malone’s putting his hand into his coat pocket. He testified that due to the prior threats, this gesture led him to believe that Malone was armed and about to attack him with deadly force.
Malone’s wife was called by the Commonwealth. On direct examination, she corroborated her husband’s testimony that the assaults were unprovoked and his testimony concerning the details and seriousness of the assaults. On cross-examination she testified to the fact that she and her husband had frequent telephone conversations concerning her *692relationship with McCreary. She stated that McCreary had been present for “most all” of the calls, that he had heard or been told about others because she “wasn’t hiding anything” from him, and that he had spoken directly to her husband on other occasions.
Later in cross-examination, she was asked by defense counsel: “Did you have an argument with your husband about the fact that Mr. McCreary was living in your house?” The prosecutor objected and the judge stated “[t]he husband-wife privilege,” adding that “[s]he doesn’t have to claim it. It can be raised by objection.” Following a bench conference which is set forth in the margin,1 the objection was sustained and questioning resumed on other topics.
Defense counsel was thereafter permitted to inquire, over the prosecutor’s objection, about an incident at a cafe where the witness and her husband had “quite an argument” in McCreary’s presence. The witness testified that she could not recall whether her husband had threatened the defend*693ant at that time. Defense counsel asked whether that answer “impl[ied] that there were times that Mr. McCreary was threatened by your husband that you know of?” An objection was then taken and properly sustained since the question was, in our view, improper as to form.
The witness was next asked: “Were there other times when you did overhear conversations between your husband and Mr. McCreary where threats were made by your husband to Michael?” The witness replied that there had been one such occasion, and defense counsel inquired as to the “substance of the threat.” The witness responded as follows: “He called the house . . . and he told me that he had a gun. That he was going to shoot me . . . [a]nd he told me that he didn’t care who was there. ‘Tell Michael and his cousin to come outside,’ and he said that he’d kick both their asses. Michael grabbed the phone from me and then they were talking.” The prosecutor moved that “the whole line be stricken” because “[t]he question was, did you hear a threat?” The judge allowed the motion.
Defense counsel next asked the witness: “After having that telephone conversation with [your husband] were you pretty well convinced that that was a threat?” On objection by the prosecutor, this inquiry was correctly excluded as “not a proper question.” Cf. Sudbury v. Department of Pub. Util., 351 Mass. 214, 220-221 (1966). The witness testified that after this call, the defendant and his cousin went outside and waited about thirty to forty-five minutes for her husband to arrive, but nothing occurred that evening. The witness then stated, without objection, that she had received “similar phone calls from [her] husband in [the] same vein.” Defense counsel asked whether she had received similar calls “with the focus on Mr. McCreary,” and whether she usually repeated the substance of the conversations between herself and her husband to the defendant. However, the prosecutor’s objections to both of these questions were properly sustained, since the meaning of the former was vague and indefinite, see Leach & Liacos, Massachusetts Evidence § 4(B)(1)(c), at *69469 (4th ed. 1967), and the latter, in context, was framed too broadly to elicit information relevant here, see Commonwealth v. Kennedy, 3 Mass. App. Ct. 218, 223 (1975). See also Commonwealth v. Slaney, 345 Mass. 135, 142 (1962); Commonwealth v. Barras, 3 Mass. App. Ct. 43, 47 (1975).
McCreary argues2 that a victim’s prior threats against a defendant are admissible in a prosecution for assault to establish self-defense; and that, therefore, testimony regarding prior threats by Malone was admissible to show that at the time of the assault, Malone was seeking to carry out those threats, and that McCreary acted out of a reasonable fear for his own safety. See Commonwealth v. Rubin, 318 Mass. 587, 588 (1945); Commonwealth v. Edmonds, 365 Mass. 496, 499-500 (1974); 1 Torcia, Wharton’s Criminal Evidence §§ 224-225 (13th ed. 1972). The defendant argues further that the exclusion of favorable testimony offered by an independent witness, if erroneous, is not necessarily cured by the defendant’s own testimony on the same point. See generally Commonwealth v. Goldberg, 212 Mass. 88, 91 (1912); Commonwealth v. Britland, 300 Mass. 492, 496 (1938). Contrast Commonwealth v. Rubin, supra at 591-592. As general propositions, we have no quarrel with these threshold contentions.
Here, however, we think that the testimony of Malone’s wife was correctly excluded in each of the instances set out above. Although prior threats are a proper subject for examination, testimony concerning them must still be introduced in a way which satisfies the formal concerns of the rules of evidence. Of the six questions in issue here, objections to four were correctly sustained, as noted above, because of improper form. In addition, the answer to a fifth question was struck on the ground it was unresponsive. That ground is clearly applicable in this instance since the question inquired as to the substance of a threat made in a conversation between Malone and McCreary, and the answer related a threat made in a conversation between *695Malone and his wife. Although a trial judge is not compelled to strike such an unresponsive answer, assuming that the testimony therein is both competent and relevant, Commonwealth v. Strickland, 11 Mass. App. Ct. 928 (1981), and cases cited, we cannot say the judge abused his discretion in doing so here. See Commonwealth v. Charles, 4 Mass. App. Ct. 853 (1976).
The remaining ruling assigned as error dealt with the question whether Malone and his wife argued “about the fact that Mr. McCreary was living in your house.” The judge’s remarks immediately following that question and the ensuing bench conference (see note 1, supra) make it apparent that his rulings on the objection sought (1) to respond to the prosecutor’s objection based on relevancy by exercising his discretion to permit defense counsel some latitude in cross-examining the wife as to events preceding and germane to the assaults (see Commonwealth v. Granito, 326 Mass. 494, 496 [1950]; Commonwealth v. Underwood, 358 Mass. 506, 513 [1970]; Commonwealth v. Franklin, 366 Mass. 284, 289 [1974]), and (2) to advise defense counsel that the disqualification expressed in G. L. c. 233, § 20, as amended through St. 1963, c. 765, § 3,3 barred testimony by the wife about the contents of private marital conversat*696ions.4 With respect to the judge’s second ruling, we think defense counsel failed effectively to “make[ ] known” to the judge the discrete ground of any error which he perceived in the ruling5 (Mass.R.Crim.P. 22, 378 Mass. 892 [1979]; Commonwealth v. Harris, 371 Mass. 462, 471 [1976]; Rule 8 of the Superior Court [effective September 1, 1980]), or to express to the judge any basis which might render the disqualification inapplicable. Given the rather confused discussion of the rulings at the bench conference, we think that the “[defendant's vague protestations against excluding the evidence were insufficient to assist the trial judge in making a rational determination of its admissibility.” Wright v. Hartford Acc. & Indem. Co., 580 F.2d 809, 810 (5th Cir. 1978). In the absence of any proper specification of grounds supporting admission of the testimony, the objection to the question was correctly sustained.6
*697The defendant argues, however, that, in view of the judge’s inclination to find the evidence relevant, the application of the disqualification to exclude the answer denied him his constitutional right of confrontation and his right to meaningful cross-examination on an important issue. See Commonwealth v. Johnson, 365 Mass. 534 (1974); Chambers v. Mississippi, 410 U.S. 284 (1973); Davis v. Alaska, 415 U.S. 308 (1974). Despite the judge’s general comments at the bench conference on the scope of cross-examination, the question as phrased was at best marginally relevant in that the subject argument was not placed anywhere within the three-month period when McCreary was living with Malone’s wife. Furthermore, the fact that Malone’s wife may have had such an argument with her husband is not clearly relevant since the issue of self-defense turned not on her state of mind but on that of McCreary himself. These considerations — coupled with defense counsel’s failure to specify appropriate grounds for avoiding the disqualification, and the fact that the jury had been made well aware of the friction between Malone and his wife over her affair with McCreary — satisfy us that the disqualification did not operate to exclude evidence which if admitted might have had a significant impact on the result of the trial. See and contrast Commonwealth v. Bohannon, 376 Mass. 90, 92-95 (1978).
The defendant makes a number of other arguments on appeal.7 Since they were not articulated below, they need not be considered here. See note 6, supra. We note in closing, however, that the exclusion of the contested testimony on threats did not prevent the defendant from making an adequate presentation of his theory of self-defense. The jury *698heard testimony regarding Malone’s prior threats from the defendant, and this evidence was supported by the testimony of Malone’s wife that she also heard such threats on at least one occasion. Moreover, McCreary received complete instructions on self-defense and the Commonwealth’s burden to disprove it, including an instruction that in passing on the reasonableness of the defendant’s conduct the jury could consider “the real or apparent requirements of the occasion, and other circumstances such as prior threats . . . .” Finally, as to the charge of assault with a knife, it may be said with some certainty that the claim of self-defense could not have succeeded on any reasonable view of the evidence, since the uncontroverted testimony established that this assault occurred after Malone had been rendered virtually helpless. See Commonwealth v. Kendrick, 351 Mass. 203, 212 (1966).
Judgments affirmed.