Real Traps Test CD Question - AVS Forum
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post #1 of 5 Old 04-06-2013, 11:31 AM - Thread Starter
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Today I downloaded the Real Traps test CD.

http://www.realtraps.com/test-cd.htm

Upon playing this on my system I was quite surprised to see that when playing the 10hz sine wave signal, the woofers on my PSB Stratus Golds were flapping allot. These speakers are not supposed to put out much of a signal below 25 hz and I'm at a loss as to why this 10hz signal is playing quite nicely through these speakers. I realize that the frequency response is more related to the cabinets inherent tuning but 10hz?

The same 10hz signal was also playing quite robustly on my older HSU HRSW12V subwoofer which also isn't supposed to do much below 16 hz.

Anyone have an idea as to what is going on here? Is this normal? Does this also mean that the HSU sub IS capable of putting out frequencies lower than 16hz or does it have more to do with the tuning port on the sub?

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post #2 of 5 Old 04-06-2013, 11:43 AM
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Originally Posted by Torqdog View Post

Anyone have an idea as to what is going on here? Is this normal? Does this also mean that the HSU sub IS capable of putting out frequencies lower than 16hz
It means you're going to blow some drivers if you're not careful. Any speaker cone will move if you feed it a 10Hz signal, and you will hear something. But unless your speaker is actually capable of reproducing 10Hz what you're hearing is harmonics, and if you feed too much power you'll smack the voice coil against the back plate and that will be the end of the driver.

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post #3 of 5 Old 04-06-2013, 12:00 PM - Thread Starter
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Originally Posted by Bill Fitzmaurice View Post

It means you're going to blow some drivers if you're not careful. Any speaker cone will move if you feed it a 10Hz signal, and you will hear something. But unless your speaker is actually capable of reproducing 10Hz what you're hearing is harmonics, and if you feed too much power you'll smack the voice coil against the back plate and that will be the end of the driver.
Thanks and YIKES! So that's what that noise was eek.gif

I did turn the volume way down after about 20 seconds of hearing that sound. I hope that I didn't do any irrepairable damage! eek.gifeek.gif

If, in the event that I did do damage, what would I listen for? A scraping sound?

ETA; I just checked and all drivers feel and sound OK. Phew!

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post #4 of 5 Old 04-07-2013, 05:45 AM
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Originally Posted by Torqdog View Post

Thanks and YIKES! So that's what that noise was eek.gif

I did turn the volume way down after about 20 seconds of hearing that sound. I hope that I didn't do any irrepairable damage! eek.gifeek.gif

If, in the event that I did do damage, what would I listen for? A scraping sound?

ETA; I just checked and all drivers feel and sound OK. Phew!

PSB Stratus Gold! I have a set, bought them new in 1989 or 90, still sound great. They play down to low 20sHz quite good in my room. I've played that same 10HZ clip on my Rythmik FV15HP and it scares me, I leave it turned down. There's a clip of a sub GTG playing that clip very high output on the same sub, on youtube. Search for it and you'll hear a cliacking sound, it scares me but doesn't seem to bother the guys there... sounds like the cone slamming to me...
BTW the Rythmik has noticeablt tighter bass than the Golds on their own, it was a nice upgrade. I had a Hsu VTF3-Mk2 before the rythmik and it was pretty good, but the golds had better sounding bass. I use music as a reference for bass quality, at around 30Hz the golds dropped off too much for movies, then came on stroner at low 20s because of speaker/seating locations and room modes.

Back on topic, the golds give good bass with their 9" woofers and large ported cabinets, but I don;t know what their port tuning frequency is, and they aren't capable 20Hz or below in any room placement I've had them in. I'd stay away from the anything below 20Hz and be careful at 20, I've seen the driver do some serious excursions - but I've never bottomed it out.

Oppo BDP-95
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post #5 of 5 Old 04-07-2013, 10:30 AM - Thread Starter
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Originally Posted by mikepos View Post

PSB Stratus Gold! I have a set, bought them new in 1989 or 90, still sound great. They play down to low 20sHz quite good in my room. I've played that same 10HZ clip on my Rythmik FV15HP and it scares me, I leave it turned down. There's a clip of a sub GTG playing that clip very high output on the same sub, on youtube. Search for it and you'll hear a cliacking sound, it scares me but doesn't seem to bother the guys there... sounds like the cone slamming to me...
BTW the Rythmik has noticeablt tighter bass than the Golds on their own, it was a nice upgrade. I had a Hsu VTF3-Mk2 before the rythmik and it was pretty good, but the golds had better sounding bass. I use music as a reference for bass quality, at around 30Hz the golds dropped off too much for movies, then came on stroner at low 20s because of speaker/seating locations and room modes.

Back on topic, the golds give good bass with their 9" woofers and large ported cabinets, but I don;t know what their port tuning frequency is, and they aren't capable 20Hz or below in any room placement I've had them in. I'd stay away from the anything below 20Hz and be careful at 20, I've seen the driver do some serious excursions - but I've never bottomed it out.
Nice to see another Gold owner. They are truly wonderful speakers that have withstood the test of time. One of the trade rags actually rated them the 16th all time best monitor at any price. Looking at your sig it appears you have the C6i center I was hoping to find. After a year or so of scouring various sites I finally gave up and just went ahead and found another Gold that I am using for my center. Glad I did as dialogue is no longer a problem at all and subtitles are pretty much a thing of the past.

I have a Rythmik FV15HP coming this Wednesday. Really looking forward to seeing and hearing what it can do.

ETA; Yes I did see that you-tube vid and thought to myself, "are they crazy"? You could definitely hear what sounded like driver slam big time and the drivers themselves were flapping violently. I couldn't tell what point they were trying to drive home (pardon the pun).

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