Author Topic: F-1X Output (Read 344 times)

vlad335 · « **on:** March 17, 2007, 07:56:08 AM »

Seems my F-1X has issues with output I think. The full range has plenty of juice but the low pass and high pass jacks don't even put out half the signal of the full range.
Is this normal?

David Houck · « **Reply #1 on:** March 17, 2007, 12:30:06 PM »

No, it's not normal.

How long have you had the F-1X?

Has this problem only recently started?

Was it working fine previously?

At the same time that you are running signals from the high and low output jacks are you also running a signal from the full range output?

Does the problem occur no matter where the crossover and hi frequency volume controls are set?

What is your overall signal path from preamp to speakers in full range mode and what is it in crossover mode?

Is the mode switch on your power amp set properly?

Try excercising the output jacks by plugging and unplugging a 1/4 jack 30 to 40 times in each jack.

You may want to exercise the crossover and hi frequency volume controls by turning them back and forth through their full range 30 or 40 times.

lothartu · « **Reply #2 on:** March 17, 2007, 08:27:39 PM »

It might be a freq cancellation issue where when you run out the high and low you're out of phase which you then end up perceiving as being lower output. Just a thought.

-Jim

jazzyvee · « **Reply #3 on:** March 18, 2007, 07:00:30 AM »

I have noticed a similar thing on my F1-x but I'm not sure really if what I'm hearing is right. I get a good strong signal from the low freq side all the time. The high freq side gives a reasonable output if I put the frequency setting all the way down to 70hz but is very tinny anywhere else.

I am using my setup in bi-amp mode with one channel feeding the left and the other feeding the right of my power amp

My signal path is as follows.

Clarkee Sig. Bass into front of F1-x, SF-2 in send and return path.

Low pass into QSC amp channel 1
High pass into QSC Channel 2

Mesa Boogie 1x15 cab fed from channel 1
Mesa Boogie 2x10 Cab fed from channel 2

If I try the output from Channel 1 into the 2x10 cab the sound is good strong and loud but with the setup back to normal the 2x10 hardly seems to get any signal. I have a feeling it's the position of the freq dial as it seems the 1x15 always gets most of the signal all the time and the 2x10 just gets the very top end so the mid range is lacking in my setup.

I've tried various settings on the F1-x and for now have removed the SF-2 from the signal path so that is out of the equation, but can't get a meaty signal from the 2x10 when it's in bi-amp mode.

Any ideas of settings to get more into the mid range of the 2x10 as at the moment it sounds like just bass and tops.
Jazzyvee

David Houck · « **Reply #4 on:** March 18, 2007, 05:56:19 PM »

JV; where do you have the hi frequency volume control set?

Also, on the QSC, check all of those switches on the back to make sure you have the proper combination for stereo. You might want to move them back and forth one time to make sure each switch if fully thrown. (I use a small flat blade screwdriver).

jazzyvee · « **Reply #5 on:** March 18, 2007, 06:05:13 PM »

I have that left on 0 the central position.

David Houck · « **Reply #6 on:** March 18, 2007, 06:12:46 PM »

JV; that control balances the two signals. Try turning it to the right some.

jazzyvee · « **Reply #7 on:** March 19, 2007, 02:59:20 AM »

hmm thats what I had before and there is hardly any signal coming through when its over to the right, just a thin top end and no meat. There is so little output that it's not worth having the cab connected....

adriaan · « **Reply #8 on:** March 19, 2007, 03:13:25 AM »

I seem to remember two of the outputs were out of phase by design (DI and full-range out?) which would account for the no meat effect.

David Houck · « **Reply #9 on:** March 20, 2007, 07:52:11 PM »

Well other than suggesting that if you haven't already, try exercising the frequency volume control to make sure that it's not just a dirty pot, I can't think of anything else to recommend short of taking it in to a good tech and have them test the circuit. According to the manual, the crossover network is driven by the same solid state circuit that drives the full range output; so I'm guessing that it wouldn't be a tube issue. You might want to open it up and do a visual inspection; see if anything looks burned or loose, being careful not to shock yourself of course.

Oh, one other thing you've probably already checked. Try switching the cables between the preamp and amp, and subsequently between the amp and speakers, just in case it's a bad cable.

cntrabssn · « **Reply #10 on:** March 21, 2007, 11:49:41 AM »

Hello,

(I guess this is more to Jazzy, but it might help Vlad too)

Does your 2x10 have a passive built in crossover? If it does, I'm wondering if you're moving into the 2x10s crossover range as you increase the crossover frequency at the F-1x. In this case, you would already be in a range where the output of the 10s is attenuated (it's passing off to the tweeter), and the high-pass filter of the F1-X increases that attenuation as it removes the low end. This might effectively reduce the midrange response of 2x10s.

Since you have a Superfilter, try running full range into your 2x10, while using the only one section of the Superfilter in high-pass mode. You can then check to see how the 2x10 behaves as you increase the Superfilter's cut-off frequency. If the response is the same as when you use the F1-x crossover, then you should probably use the 2x10 full range with the 1x15 acting as a sub. You will then have to worry about the phase difference between the F1-x full-range and crossover outputs.

Thanks,
- nate.

jazzyvee · « **Reply #11 on:** March 21, 2007, 12:09:46 PM »

I think I understand what you are saying. There is a crossover control at the back of both speaker cabs. I've always left them in the mid position so at the weekend when I have a bit more time I'll try the options you suggest nate and see how I get on.

When you say use the 1x15 as a sub I assume you mean leave that in the Low pass channel?
Jazzyvee

cntrabssn · « **Reply #12 on:** March 21, 2007, 05:50:13 PM »

Hi Jazzyvee,

Yes, that's what I mean. Leave the 1x15 connected to the low pass channel, but connect the F1-x full range output to the other amplifier channel to drive the 2x10. Remember that these outputs will now be out of phase, so you will need to reverse the speaker terminal connections on one channel only. This will be a bit of a challenge if you're using Speakon or 1/4 inch connectors.

Thanks,
- nate.

0vid · « **Reply #13 on:** March 22, 2007, 01:56:17 AM »

I am not sure that there is actually anything wrong with the F1X with the two posters who reported issues....the high out seems to be working but that's the way it works....

If you have a full range speaker and try running the high out to it whilst experimenting with the freq. knob, you will find that above 250Hz, the bottom end almost completely dissapears. This is not an anomaly .

If you are running a 1X 15, and a 2X10 (without tweeter) in a bi amp set up, you will find that the 2 X10 will need to crossover at maybe 100 hz for you to 'feel' that the 2X10 is working. Frankly you could use the 1X15 and crossover at 250Hz and use a much lighter top ,... say a PA top with a 1X 8.

If you run the 1 X 15 with the low pass, and the 2 X 10 from full range you will have a low end bump, and you might as well splice the full range out and drive both at full range.

I run a bi amp set up: F1X low pass into 800 watt bridged mono amp feeding a 2 X 12 sub. F1X hi pass: feeding a 300 W bridged carver power amp, 1X12, 1 X 6, horn 3 way cab (internal passive crossover). I normally have the F1X crossover at 125 - 150 hz. The mismatch in power amps is not an issue, as the power needed above that frequency is not as high for a balanced audio spectrum which is what I am after. I have the hi out knob at 0.

You'd need the those 800 watts to flap trousers though, and that air movement really works below 150hz anyway.

You typical powered monitors run on the same idea, two differently power rated amps feeding the woofer and the tweeter.

In my case, my 1 X12 cab can actually run on its own as a full range cab, and I use this for small gigs or rehearsals, And frankly as a top, it is OTT as far as weight is concerned, for what I need it to do, which is to reproduce the top end beyond 150hz.

To this effect I am looking into building a lighter top based on 8 speakers.

(Message edited by 0vid on March 22, 2007)

vlad335 · « **Reply #14 on:** March 22, 2007, 09:45:20 AM »

How long have you had the F-1X?
About 3 years. I got it used as part of a trade thru Talkbass.com

Has this problem only recently started? Was it working fine previously?
Not sure... I just added another power amp to my rig where I was using only one previously. the way my rig was setup, when I bridged the amp into one speaker, I used the full range output. When using the high and low pass outputs, I ran the amp in stereo where the amp put out far less power so the LP/HP could have had far less gain that I attributed to less power from the amp. I hope that makes sense. It could have been this way all along and I didn't realise it.

At the same time that you are running signals from the high and low output jacks are you also running a signal from the full range output?
I just found out that you can do this yesterday actually. THats how I noticed the difference.

Does the problem occur no matter where the crossover and hi frequency volume controls are set?
Yes

What is your overall signal path from preamp to speakers in full range mode and what is it in crossover mode?
Right now I am running the alembic Full range into a bridged QSC RMX850 running 2 Ashdown cabs in 4 ohms while using the low out to a Bridged mono QSC PLX 1202 amp powering an 18 speaker in 4 ohms. I have to use the full range to get any acceptable volume to my ashdowns.

Is the mode switch on your power amp set properly?
yes, both amps bridged.

Try excercising the output jacks by plugging and unplugging a 1/4 jack 30 to 40 times in each jack.
Did this

You may want to exercise the crossover and hi frequency volume controls by turning them back and forth through their full range 30 or 40 times.
Tried this as well.

Very intriged by the statements on this thread about phasing. Never knew this... Can someone explain? Would my 2 amps be running one speaker setup out of phase if I use the low pass and the full range? Which one would be out of phase? I can easily correct this with my speakers as I am using banana plugs on the amp end.