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Is my Paradigm X-Over 30 unit defective?


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5 replies to this topic

#1 of 6 OFFLINE   ClaudeL

ClaudeL

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Posted November 18 2003 - 05:37 AM

Hi all,

Since a good month, I played with different low pass / high pass crossover settings and I find something isnt right. I have a DIY Tempest subwoofer and my mains are Paradigm Monitor 9 v.3. These floorstanders are powered by an Anthem MCA-20 stereo power amp and the av/receiver is a Yamaha RXV-630.

So to only use the Paradigm crossover unit, I set my towers to large (useless anyway because I use the main-out of my av/receiver), I use "MAIN" for the bass (I can choose between SWF, MAIN, BOTH. The Tempest plate amp crossover is logically set at its maximum, at 150 Hz, in order to not have a the entire signal from the X-30. Normaly, I use 50 Hz for the low AND high pass because the Paradigm have plenty of mid-bass kick and I let the Tempest to do the rest. So now, I begin to explain whats happening...

One day, I suddenly wanted to have the mid-bass kick from the Tempest so the towers would have to work less. I changed first the high pass setting to 80 Hz, by placing the connections behind the crossover unit at the right place and I changed the low pass to 80 Hz too, by turning the low pass knob. Then, I played different songs, songs which are very dynamic...

!!! Posted Image !!! To my big surprise, I heard LITTLE changes from the bass produced by the Tempest. In fact, I didnt find to have more mid-bass kick from it. In the other way, the changes in bass/sound from the towers was obvious and I could even see that the woofer excursion was reduced during kick drum passages. Not so long after, I changed the low pass seting from 80 to 35 Hz (lowest setting). Woaa... very little changes again. Its like at either 35 or 80 Hz, some frequencies arent well filtered at all.

So here are some numbers I would like to share with you. I measured the outpout very near the woofer, something like 6" because I didnt want the room to have an effect on the results. If you dont already know, the low and high pass of the Paradigm X-Over unit reduce the outpout by 18 dB/octave. I played a tone of 50 Hz for the test.

Crossover setting==========Measured output
-----35 Hz----------------------99 dB
-----80 Hz---------------------101 dB
-----120 Hz--------------------104 dB
-----150 Hz--------------------107 dB


I dont know if its me, but I find the results weird for a 50 Hz note!

#2 of 6 OFFLINE   ClaudeL

ClaudeL

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Posted November 19 2003 - 08:33 AM

Wow!! Not even a single answer for me? I want to add also that in that test which show the numbers, ONLY the subwoofer was working.

#3 of 6 OFFLINE   Wayne A. Pflughaupt

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Posted November 19 2003 - 12:36 PM

Quote:
Wow!! Not even a single answer for me?
It’s probably because your post is confusing. For instance, it sounds like you have a signal from the Tempest plate amp feeding the X-30 - which of course, makes no sense all. Perhaps you could try to explain it all again.

Regards,
Wayne A. Pflughaupt

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#4 of 6 OFFLINE   ClaudeL

ClaudeL

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Posted November 19 2003 - 02:41 PM

Quote:
it sounds like you have a signal from the Tempest plate amp feeding the X-30 - which of course, makes no sense all.

No no... a signal FROM the X-30 TO the Tempest plate amp. That makes sense actualy... The X-30. Ok, so Im gonna explain shortly how it does work, its pretty simple.

A full range signal goes FROM the MAIN-OUT of the receiver TO the Low level inputs of the X-30. Then, for the high pass filter section, the signals goes FROM the X-30 TO the stereo power amp. Finally, for the low pass filter section, the signal goes FROM the X-Over to the sub plate amp.

Im sorry, I should have wrote those precisions before. Posted Image

#5 of 6 OFFLINE   Wayne A. Pflughaupt

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Posted November 20 2003 - 05:02 AM

Quote:
the signal goes FROM the X-Over to the sub plate amp TO the X-30 crossover unit.
There it is again: The signal goes from the X30 to the sub amp (okay, sounds right) and then back to the X30??

Doesn’t matter, really. If you’re trying to figure out if the X30 is defective, here's how to do it. You will need test tones and a SPL meter. You also have to know what the X30’s slopes are (12dB/octave, 18dB/octave, etc.).

To test the low pass, disconnect the mains and play two test tones, one at the crossover frequency and one an octave higher. An octave higher is double the frequency – i.e., if the crossover point is 80Hz, then an octave higher is 160Hz. The second tone should measure lower pretty close to the amount of slope.

Just the opposite for the high pass, except you half the figure for the second tone – i.e., 80Hz vs. 40Hz.

Regards,
Wayne A. Pflughaupt

My Equipment List
“A nice mid-fi system,” according to an audiophile acquaintance.

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#6 of 6 OFFLINE   ClaudeL

ClaudeL

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Posted November 20 2003 - 01:12 PM

OMG!!!!!!!!! Again a mistake from me in my reply!!! I just edited it, NOW it makes sense!!! Posted Image Whats happening with me??? I really know of what Im talking about but my hands just dont type that!!! Im so sorry for these confusions but well, I will try what you explained to me. What you said seems to have a lot of sense LOL! Posted Image I'll get you back tomarrow or satursday for the results. Thanx a lot for you help! Posted Image





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