A Problem with my 705?

[Ronel S]

Hello Everyone,

This is my first post and sorry for my english. I know I would be able to get insights from this forum.

I just got my new pair of 705, 3 weeks ago. This is a replacement of my 2-year old 602's used for my 2 channel stereo system. On the first time I heard my 705, I was not really impressed of the sound and even regretted of disposing my 602's. The fact was, my 602's sounded superior than my 705!

I understand that these speakers needs more time to break-in. So, I told myself to be patient and waited a little more time and I'm really happy these days of what my speakers reveal. Finally, they open up, and beat my 602s with a wide margin. The highs are crisps, the mid is clear and the lows are more detailed.

Now, how come with this I have my problem? When I played my NCH test tones I downloaded from the net and burnt it to my CD. Somewhere in the 13khz tones (pink noise) to 20khz, there is that hizzing sound (much pronouced than the test tones) associated with the tones, as if the tweeter begin to tear apart. I began to worry then, and thinking that my new speakers might be defective. I pulled out the CD and started to play my music albums, but didn't hear any similar sounds.

Does anyone have experience like this? Is it normal for the 705 being capable of the high frequency (the specs states that it can go as high as 25khz)?

I would appreciate one's expertise on this matter. Thanks in advance.

Ronel S.

[junior77blue]

Hmm...I think I've had the same problem. I will have to run through some test tones. I always thought it was something resonating around the speaker and not the speaker it self.

[BlazeMaster]

I noticed this with only one of my 704s a while back. It seems that there is this distortion coming out of one of the 704s in higher frequency range. I have no way of measuring the exact frequency range that this happens at, but I know it's pretty high.

[grit]

I cant comment from experience, but I'm thiniking crossovers. Check your cables and binding posts (just to make sure).

[Ronel S]

Thank you guys for your inputs. Now I can sleep well knowing that this also happens with your speakers. I'm thinking if the crossover is the suspect, then how come the 602s and 705 are of the same crossover cutoff, 4khz and 3.7khz but didn't happen to the 602s. Also, at this point of 13khz to 20khz frequency range the sound is solely produced by the tweeters. Therefore, I can conclude that the hizzing sound is coming from the tweeters and not on the woofers.

Anyway, thanks again and I have to check my cables also.

[junior77blue]

Keep us informed of what you find. I will try to play some test tones as well and see what frequency this happens (if it happens) on my 705s.

[junior77blue]

I was unable to create the tweeter anomoly using test signals and medium listening levels. What type of volume are you listenting at?

I will have to find the particular track which I first noticed this as it was repeatable with the track. Could just be the source...hmmm...

[BlazeMaster]

I was able to notice it on some of the songs on Nora Jones first CD. can't think of the name on the exact song, but it's usually when she hits her high notes.

[grit]

Hmmm, lemme toss this idea out. On Norah Jones' "Sunrise", when she hit's "S"-sounds, the speaker crackles slightly, almost as if Norah was too close to the mic when she recorded the track.

At first, I played SEVERAL cd's through my B&W 703's to see if the left tweeter was broken. When I had difficulty duplicating the problem, my ignorance led me to believe that was simply the system showing off the detail of the recording.

While I was A/B testing interconnects, I discovered a difference between the analog bypass mode of my Rotel 1060 and the DAC output of my 1068 (digital source was still the 1060). Norah was NOT too close to the mic at all.

There's a quality difference between the DACs in the 1068 vs 1060. IMO, the 1060 sounds better. However, the 1060 (or at least the 1060, coupled with my other equipment - Rotel 1068, Rotel 1075, B&W 703's), caused that crackling sound.

In finally corrected both problems by purchasing a Rotel 1072 CD player. The sound is musical, wonderful, and there is no cracking or other problems.

The short version - It may be the DACs (or at least the DACs combined with your other equipment) and not your speakers.

[RJW1138]

Ronel, did your test tone come from an MP3 or some other compressed format? If so, there's your problem. You're hearing some kind of compression artifact that becomes very pronounced in the high frequencies. I think it manifests itself as a type of intermodulation distortion, and you hear a bunch of other frequencies that you're not supposed to. I've heard this on pretty much every high frequency test tone or sweep that I've downloaded in compressed format, on many speakers, headphones, etc.

Now if your sweep is already uncompressed, then yeah, you might have a problem, and you should probably have it checked out.

But if I was right, you could try to find a sweep in uncompressed format to satisfy your curiosity, but I'd rather suggest that you simply throw on some tunes and enjoy your speakers instead. :-)

[junior77blue]

But if I was right, you could try to find a sweep in uncompressed format to satisfy your curiosity, but I'd rather suggest that you simply throw on some tunes and enjoy your speakers instead. :-)

I would agree with you on this, however, when I did hear this anomaly it was from an audio CD, granted it was recorded from an MP3. So, I will have to find that track and then use the original master CD to see if it can be duplicated. But I think your on to something with the compression artifact.

[Ronel S]

Ronel, did your test tone come from an MP3 or some other compressed format? If so, there's your problem. You're hearing some kind of compression artifact that becomes very pronounced in the high frequencies. I think it manifests itself as a type of intermodulation distortion, and you hear a bunch of other frequencies that you're not supposed to. I've heard this on pretty much every high frequency test tone or sweep that I've downloaded in compressed format, on many speakers, headphones, etc.
:-)

Sorry for the delayed response 'coz I was out of town. Anyway, the test tones that I have was downloaded from the internet and copied on my CD as WAV files. I really don't have any idea if this is compressed or not. Nonetheless, the same was also played on my floorstanding speakers (and I have done this many times on my wharfedale speakers) and I didn't hear any cracking sound.

Another thing to note was that, at the last track (20khz), I know it is normal that the tones is no longer audible, however, the cracking sound is still there the same volume at the last 3 previous tracks. Volume was at moderate level, (at least 1/4 of my rotel integrated amp) enough to fill my room with music.

Thanks again to all who give special attention to this problem. It might not be a problem/defect on my speakers but at least I am enjoying listening to these new babies.

Ronel S

PS. By the way, my humble 2-channel system is being powered by Rotel RA-03 integrated amp, Ixos banana plugs (not biwired) on Ixos speaker wires (11 ga) with NAD C542 CD player as the source.

[paultom84]

Was experiencing the same problem. Sounded as if the tweeter was blown. When I removed it to look for the part number I fixed the problem. The plastic casing was not seated properly. Once I replaced it the speaker sounds find.

Paul