Did I ruin my Totem Arro?

[SwA.]

I recently bought a pair of 2nd hand Totem Arro’s.

In one, and only one, of the speakers, I hear a buzz, clearly coming from the lower speaker (not the upper tweeter). I switched the cables, so even if I switch the left & right channel, it is the same speaker which has a problem. It is not the cable (or any of the equipment upstream) that seems to cause the problem. The buzz is very noticeable in the lower bass frequencies (40-60Hz), e.g. when a double bass is playing.

While auditioning the speakers during the twenty minutes or so I listened to them at the private vendors place, I did not notice the buzz. I did play some music with pronounced bass (e.g. ‘Mi Corazon’ by Brandt, Brauer & Frick).

At home, it was only after a couple of days that I started noticing the buzz. And now, I can’t bear it anymore.

Now, my question:

• Option (a): The buzz was already there when I bought the Arro’s, but I did not notice it at first.
• Option (b): I damaged one of the Arro’s myself with my pre/poweramp combination.

My gear:

• DAC: Topping D70s, xlr out, output volume 5v (if I am not mistaking)
• Preamp: Shiit Freya+ in tube mode (4x Tung-Sol 6SN7GTB), using balanced in- & outputs.
• Power Amp DIY Hypex Nilai 2x256w at 8Ω, 2x300w at 4Ω, power amp set at low gain (12dB)
• Speakers: 2nd hand Totem Arro, impedance 4 Ω, recommended power 20-80w, sensitivity 87dB

Option (a) seems possible, since I had a listening companion for several hours, and at the time she did not notice the buzz either.

But, to be more sure, in your opinion, is option (b) possible? Given the 2x300w (at 4ohm) of my power amp… which might be too much for the Arro’s.

How loud did I play? In general, the volume knob of the Freya was between 10 & 12 o’clock, but during a couple of (long) evenings it was between 1 & 3 o'clock. Sound levels never exceeded approximately 85dB (at a distance of 2 meters). At this level, the ‘good Arro’, still played a very clean sound.

I want to have the Arro repaired (or I will try to find another pair) since I am super happy with their sound. But I am trying to figure out whether I need to replace my power amp before using the Arro’s again.

I am not familiar with the technicalities of audio equipment, so I hope to get some competent advice of someone who is.

 

[GXAlan]

The Freya+ can hit 15V output and the volume level will depend on what your DAC is outputting.

Then you add another 12 dB getting you 60V.

Which is 900 watts into 4 ohms. So you definitely can overdrive the Arro with your electronics.

The next question is 85 dB at 2 meters. That means you’re only using 2 watts or so, so you should not have over-driven your Arro’s with that.

Hum is different than buzz. If it’s a buzz, you will want to see if the buzz is coming from the woofer or the speaker. If it sounds like hum, like mains hum, then there could be something weird. One thing to try is to run the Freya in passive mode so that you eliminate the possibility of some weird interaction with one of the tubes.

To be clear, the hum follows the speaker even when you reverse the left and right channels? What if you move the speaker that is affected a few feet?

If it’s coming from the speaker then there could be a loose screw or loose piece of dampening inside the speaker.

 

[SwA.]

The Freya+ can hit 15V output and the volume level will depend on what your DAC is outputting.
View attachment 340698
Then you add another 12 dB getting you 60V.

Which is 900 watts into 4 ohms. So you definitely can overdrive the Arro with your electronics.

The next question is 85 dB at 2 meters. That means you’re only using 2 watts or so, so you should not have over-driven your Arro’s with that.

Hum is different than buzz. If it’s a buzz, you will want to see if the buzz is coming from the woofer or the speaker. If it sounds like hum, like mains hum, then there could be something weird. One thing to try is to run the Freya in passive mode so that you eliminate the possibility of some weird interaction with one of the tubes.

To be clear, the hum follows the speaker even when you reverse the left and right channels? What if you move the speaker that is affected a few feet?

If it’s coming from the speaker then there could be a loose screw or loose piece of dampening inside the speaker.

 

[SwA.]

Thanks. I guess 'buzz' would be a better word than 'hum' (I changed it in the OP). The buzz is clearly coming from the lower speaker of the Arro, not the upper tweeter. And yes, the buzz follows the speaker if I reverse the channels. I also added my DAC to the description of my gear.

 

[terryforsythe]

If the woofer voice coil is damaged, you should be able to detect this by GENTLY pushing, directly in without any lateral movement, the woofer and detecting whether there is any rubbing of the voice coil against the front plate or pole of the magnet structure. You might first try on the speaker without any hum to see if your technique is correct. There should be no rubbing on the good woofer if you are doing it correctly.

That being said, as GXAlan said, because it is a hum and not a buzz (or scratchy sounding noise), likely the speaker is not damaged. Also as GXAlan said, reverse the speaker cables so that the left channel is plugged into the right channel, and vice versa, and listen to detect whether the hum switches to the other speaker. If so, probably it is an issue with your electronics - maybe a bad capacitor in a power supply.

 

[terryforsythe]

Thanks. I guess 'buzz' would be a better word than 'hum' (I changed it in the OP). The buzz is clearly coming from the lower speaker of the Arro, not the upper tweeter. And yes, the buzz follows the speaker if I reverse the channels. I also added my DAC to the description of my gear.

You responded while I was still typing.

If the buzz follows the speaker and not the cable, then it is an issue with the speaker. Check whether the voice coil is damaged as I indicated in my post above. If you feel any rubbing, then it probably needs a new woofer. If you do not feel any rubbing, it could be something else. Somebody would need to get inside the speaker to investigate.

 

[AdamG]

Thanks. I guess 'buzz' would be a better word than 'hum' (I changed it in the OP). The buzz is clearly coming from the lower speaker of the Arro, not the upper tweeter. And yes, the buzz follows the speaker if I reverse the channels. I also added my DAC to the description of my gear.

Take a recording of the sound of the hum/buzz and post the video/audio recording. This will aid in a better diagnosis of the problem.

Welcome Aboard ASR @SwA.

 

[RobL]

I had a floorstander (polk I think) with an intermittent buzz sound, ended up being a loose cable inside. Might be worth pulling the bass driver out and having a peek inside.

 

[SwA.]

Take a recording of the sound of the hum/buzz and post the video/audio recording. This will aid in a better diagnosis of the problem.

Welcome Aboard ASR @SwA.

Two files attached. Never mind the recording quality (just with my iPhone). I think the difference is clear between the good & the bad Arro.

 

[SwA.]

If the woofer voice coil is damaged, you should be able to detect this by GENTLY pushing, directly in without any lateral movement, the woofer and detecting whether there is any rubbing of the voice coil against the front plate or pole of the magnet structure. You might first try on the speaker without any hum to see if your technique is correct. There should be no rubbing on the good woofer if you are doing it correctly.

That being said, as GXAlan said, because it is a hum and not a buzz (or scratchy sounding noise), likely the speaker is not damaged. Also as GXAlan said, reverse the speaker cables so that the left channel is plugged into the right channel, and vice versa, and listen to detect whether the hum switches to the other speaker. If so, probably it is an issue with your electronics - maybe a bad capacitor in a power supply.

I tried the 'gently pushing' technique. I notice no difference between the good and the bad Arro.

 

[SwA.]

Thank you guys. I think that, with your help and suggestions, the problem is solved. One of the wires going to the woofer had some loose strands. At low frequencies they brushed against the metal of the woofer. I cut them away. The buzz is gone. I attach two pictures, but the strands are kind of difficult to see (I only noticed them while playing some bass sounds with the woofer hanging half out of the cabinet).
By the way, I also reached out to Totem Accoustics in Canada. Based on the (handwritten!) serial number, It seems these Arro's are 25 years old and Totem wanted to send me a replacement woofer (I don't know at what cost, but just the idea that they would be able and willing to do that, is great).
Furthermore, they commented that

a powerful amplifier controls the woofer more adequately . The object is to control the output knowing this is a 4 inch driver designed for musicality and not dB output

So it seems I don't need to replace my power amp.

Which leads me to a final question. Can somebody tell me how you calculate the power that goes into the speakers? I understand that you have to take into account the output of the DAC (in this case 5v using XLR output), the gain of the preamp (maximum 15v in tube mode), the volume setting, i.e. the dB at x meters coming out of the speakers which have a 87dB sensitivity... What is the formula to calculate the input power in watt if you listen e.g. at a 85db sound level at a distance of two meters? Just curious. I don't know anything about the relationships between ohm, volt, watt, dB, gain etc... But I am able to understand high school math. @GXAlan, maybe you can explain how you calculated the '2 watt or so' that I am feeding my speakers?

 

[Sokel]

It's not clear in the pic,the strands your talking about are coming from the voice coil?
Cause if they do it's better to take an overall check,these strands don't spit by their own.

 

[SwA.]

I am not sure, and I closed everything up again. As long as it works, I am happy. And if I run into trouble (or buzzing) again, I will replace the woofer (140 CND$)

 

[Sokel]

I am not sure, and I closed everything up again. As long as it works, I am happy. And if I run into trouble (or buzzing) again, I will replace the woofer (140 CND$)

I would insist if not for the Nilai up the road,it has short circuit protection so your not in danger.
But keep an eye (or ear) on it for good or bad.

 

[Penelinfi]

Looks like the tinsel leads unravelled/broke?

Also you won't necessarily protect your speakers by using a less powerful amplifier. Clipping can blow up tweeters.

It comes down to sensibility. Does the woofer reach excursion limits in case of bass drivers.

What I tend to do is limit the volume at the amp and adjust the source. Not sure if that affects sound quality, but it means that you can not accidentally or casually overdrive the speakers, as 100% at source is just below what seems too much for the speakers. Or you can always limit it lower too.

Tinsel leads can break over time too just from use. Some are designed better than others, or, running woofer at over excursion all the time will wear them out quicker. Can be fixed if you're technical with speaker repair, otherwise it's new woofer time when they finally all break.

 

[SwA.]

Looks like the tinsel leads unravelled/broke?

Also you won't necessarily protect your speakers by using a less powerful amplifier. Clipping can blow up tweeters.

It comes down to sensibility. Does the woofer reach excursion limits in case of bass drivers.

What I tend to do is limit the volume at the amp and adjust the source. Not sure if that affects sound quality, but it means that you can not accidentally or casually overdrive the speakers, as 100% at source is just below what seems too much for the speakers. Or you can always limit it lower too.

Tinsel leads can break over time too just from use. Some are designed better than others, or, running woofer at over excursion all the time will wear them out quicker. Can be fixed if you're technical with speaker repair, otherwise it's new woofer time when they finally all break.

Yes, that's right, one of the 'tinsel leads' was unraveled. After I put the Arro on its right place, I had to reopen it again, because the scratching kind of buzz reapeared. The lead still touched the metal of the woofer. Now it seems really solved, although I guess that it won't last forever. But an investment of €100 euro in a new woofer, seems very reasonable for speakers that are a match made in heaven for my taste and room.

 

[Zek]

The lead still touched the metal of the woofer.

Can you turn the driver 90, 180 or 270 degrees to avoid the wire touching the basket metal?

 

[terryforsythe]

So it seems I don't need to replace my power amp.

Which leads me to a final question. Can somebody tell me how you calculate the power that goes into the speakers? I understand that you have to take into account the output of the DAC (in this case 5v using XLR output), the gain of the preamp (maximum 15v in tube mode), the volume setting, i.e. the dB at x meters coming out of the speakers which have a 87dB sensitivity... What is the formula to calculate the input power in watt if you listen e.g. at a 85db sound level at a distance of two meters? Just curious. I don't know anything about the relationships between ohm, volt, watt, dB, gain etc... But I am able to understand high school math. @GXAlan, maybe you can explain how you calculated the '2 watt or so' that I am feeding my speakers?

You need the total gain of the system, and thus also need account for the amplifier's gain. Nonetheless, the volume knob will determine the power coming out the end. So, I wouldn't concern yourself with calculating all of the gains.

P = V^2/Z, where P = power, V = voltage and Z = impedance. Z is analogous to resistance, but includes a phase parameter. A speaker represents a complex impedance load to the amplifier, and is not constant across all frequencies. So, for a particular volume setting the output power will be different at different frequencies, depending on the speaker's impedance at those frequencies.

Here is an article that discuses a speaker's output power vs input power for a given sensitivity:

Understanding Speaker Sensitivity - Geoff the Grey Geek

A simple explanation on how to understand and use Speaker Sensitivity specifications. Includes calculators to determine how loud your speakers will be.

geoffthegreygeek.com

 

[SwA.]

Can you turn the driver 90, 180 or 270 degrees to avoid the wire touching the basket metal?

Good idea. I checked. It's possible, but the driver is already in a position with the wires at the bottom side.