| Author | Message | ||
| vlad335
New Username: vlad335 Post Number: 6 Registered: 1-2007 |
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? | ||
| davehouck
Moderator Username: davehouck Post Number: 4877 Registered: 5-2002 |
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
Advanced Member Username: lothartu Post Number: 218 Registered: 8-2003 |
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
Senior Member Username: jazzyvee Post Number: 787 Registered: 6-2002 |
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 | ||
| davehouck
Moderator Username: davehouck Post Number: 4886 Registered: 5-2002 |
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
Senior Member Username: jazzyvee Post Number: 789 Registered: 6-2002 |
I have that left on 0 the central position. | ||
| davehouck
Moderator Username: davehouck Post Number: 4887 Registered: 5-2002 |
JV; that control balances the two signals. Try turning it to the right some. | ||
| jazzyvee
Senior Member Username: jazzyvee Post Number: 791 Registered: 6-2002 |
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
Senior Member Username: adriaan Post Number: 1336 Registered: 6-2002 |
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. | ||
| davehouck
Moderator Username: davehouck Post Number: 4890 Registered: 5-2002 |
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
Junior Username: cntrabssn Post Number: 44 Registered: 6-2002 |
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
Senior Member Username: jazzyvee Post Number: 793 Registered: 6-2002 |
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
Junior Username: cntrabssn Post Number: 45 Registered: 6-2002 |
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
Member Username: 0vid Post Number: 66 Registered: 4-2003 |
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
New Username: vlad335 Post Number: 7 Registered: 1-2007 |
"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. | ||
| adriaan
Senior Member Username: adriaan Post Number: 1362 Registered: 6-2002 |
The idea is that you run one output to the front-of-house system, which will be out-of-phase with the output that you run to the on-stage rig. This way you should have a cleaner low-end response both on-stage and in front for the audience. | ||
| crgaston
Advanced Member Username: crgaston Post Number: 363 Registered: 11-2005 |
Hi David, Checking the specs on the QSC website, it loks like the voltage gain on your RMX is about 25% less than on your PLX. This may have something to do with your issue. Also, depending on how your bass is eq'ed, there may not be much power going to the high-pass output, anyway (as Raymond pointed out above). Both these factors could be contributing to the problem. Try this... Using one speaker and one amp, play for a minute or so through the full range out to get a feel for the volume. Then disconnect it and use the low-pass out, with the HF level set at 0 (12 o'clock) and your Crossover frequency set as high as it will go, or fully clockwise. Unless the extreme high end is a major part of your sound, the levels should be pretty even between the two jacks. If there is still the drastic dropoff, there is a problem. Regarding phase, technically it is the low-pass that is out of phase, but effectively it doesn't matter which banana plug you flip since there are only two signals. Hope this helps, Charles | ||
| 0vid
Member Username: 0vid Post Number: 67 Registered: 4-2003 |
<<<"Does the problem occur no matter where the crossover and hi frequency volume controls are set?" Yes >>> This sounds like your unit has a defective crossover section. | ||
| davehouck
Moderator Username: davehouck Post Number: 4898 Registered: 5-2002 |
For more on the subject of phase shift, go here. | ||
| dfung60
Advanced Member Username: dfung60 Post Number: 238 Registered: 5-2002 |
I think your gear may be working just fine. The problem is that biamping and using the crossover is just not producing a good result for you. The first problem is that a biamp system is a good solution for full range sound sources (recorded music, keyboards, drums). Your bass is, uh, a BASS instrument and doesn't have so much high end output that the upper split has that much to do. The low E fundamental is 40Hz; an octave higher is 80Hz, the fundamental of the highest E you can play on the G string is 160Hz. The first (octave harmonic) of that high E is 320Hz and even the third harmonic (the next octave is still only 640Hz. With the crossover frequency dropped down to the lowest range (70Hz) you'll find that only higher notes will be routed to the 2x10 cab and, simultaneously, you'll be robbing the 1x15 cab of most harmonics and many fundamentals. By the time the crossover freq is up to 12 o'clock, pretty much all the signal will be sent to your 1x15 and your 2x10 won't have much to do. This is not to say that there's not much bass business above 1000Hz, but if you're not slapping or playing with an extremely bright sound, there probably won't be that much going on. While the crossover is splitting things up possibly in a somewhat non-useful fashion, you're also suffering an enormous power loss because of the biamping. I don't know which amp you're using, but what's happening here is that the low-end channel is being fully used but is only driving one speaker now instead of two. The high-end amp is mostly not doing anything because of lack of program material, so you've effectively lost that amp power as well as getting no acoustic output from the 2x10 cabinet. As opposed feeding both channels with a full range signal, you've lost 50% of the amplifier power and 50% of the speaker area of your rig - that's "only" 6dB, but a very significant loss. On top of that, in your original setup, you were running the power amp in bridge mode. When you couple the amps up in this way, it acts as though the impedance of the speakers was reduced by half. Numerically, that is a 2x increase in amplifier watts (again, another 3dB). And in practice, it's probably even higher than that since you were probably running the two cabinets in parallel which would again double the amplifier power! All those splits are costing you a lot of perceived output and that's why things sound lackluster. Biamping is really useful when you have the right circumstance. If you have a full-range (bass to high treble) signal and you want it to be really loud then this is a good application. The problem with amplifying a piano, synth, or even voice is that the best speaker for high frequencies is a small one which can vibrate faster and the best speaker for low frequencies is a large one that can move a lot of air. But the big bass speaker is too massive to reproduce highs and the tweeter will melt down if you try to drive it with high current bass signals. So, you split the signal with a crossover and let each speaker do it's own specialized job. For a bass rig, there's not that much for the high end channel to do, and a 2x10 cabinet is too big to reproduce the highs well anyway (2x10 might be a gutless low end cabinet for us bassists, but it's bigger than most woofer in most full range systems). So, if I were you, I'd switch back to your original setup - bridge the power amp, feed it with the full range output from your F1-X, and run both speakers full range and parallel. You'll probably be a lot happier. If you want a little more flexibility, then run the amp unbridged, feed both channels with the full range output, and you'll be able to use the gain controls on the amp to control the balance of the two cabinets independently. You can verify that the crossover is working properly, but feeding it with a full range signal (e.g., your iPod or the like). You'll hear that the 2x10 is plenty busy then, although you may not like the sound of your rig vs. something with flat response. The crossover (whether passive or active) doesn't just protect the tweeters from getting cooked. If the tweeter could take the power and you fed both speakers with full-range signal, you'd find that there would be certain ranges where both speakers were actively able to reproduce the sound. The sound in those overlap areas will be terrible, because the time response of the speakers won't match (the woofers mass will blur transients for instance). When you have time shifts and blurring like this, you get phase cancellation which can make things thin and/or honky sounding. If this is in the midrange, where human hearing is the most sensitive, it will make for annoying sound. The crossovers divide up the spectrum and reduce these problems, and a properly designed system is tweaked for good results in the overlap areas. Your F1-X crossover doesn't have the adjustability to make these sorts of compensations. In fact, these sorts of adjustments are exactly what all those "weird" trimpots are tweaking in Ron's ELF Integrator. I hope this helps. Having all the fun/advanced stuff is cool, but often the simple setup will yield the best sound. David Fung | ||
| jazzyvee
Senior Member Username: jazzyvee Post Number: 797 Registered: 6-2002 |
I think you guys are right, I tried the full range out into the 2x10 and the low pass into the 1x15 and even with the out of phase situation talked about, the output is much fuller in sound than with the high out into the 2x10. So I'm gonna do some more experimenting to see how to get the beef coming out of both speakers. Cheers Pity I didn't know this before I bought the whole setup as I may have not bothered. Cest La vie. Jazzyvee | ||
| palembic
Senior Member Username: palembic Post Number: 2533 Registered: 9-2002 |
Hi Friends As you probably read at another place I got Bonnie back but Edwin (who brought her back) located the problem in a bad working speaker. It seemed that I blew the 15" of my Glock, the QSC was too powerfull! SO it will be replaced by a Beyma 700W by 8ohm Neodymium speaker and an extra bassreflection hole. Edwin also gave me the advice to run a "full range" signal from tha back of the F1-X in Bi-amp to the 2x10 inch with horn. And feed the Beyma only with freq below 100 (so cross point at 100HZ). I will keep in mind about this "opposite-phase" thing: so IFF I get things right the FULL RANGE out at the back of the F1-X is in opposite phase as the channel of the low-freq when running in Bi-amp???? The repair-dude suggested a kind of small box wherein polarity is changed to put between the FULLRANGE outpunt and the input of the QSC-channel! Some advice to keep in mind! Paul TBO Yep ...i KNOW to watch out for blowing the 2x10 too!!! | ||
| dfung60
Advanced Member Username: dfung60 Post Number: 250 Registered: 5-2002 |
In many electronics, the phase is reversed each time you go through another amplification stage. I don't know if this is the case in the F1-X, but seems like it is probably so. But it doesn't really matter! There's no standard for phase in speaker cabinets, so if you're mixing manufacturers cabinets, you only have a 50% chance that the cabinets will be in phase. You have to hook 'em up and listen to the results to determine whether the phase relationship is right or not. You don't really need an external box to reverse phase. If you need to reverse phase in the 1x15 cab, you can probably open up the cabinet and reverse the leads on the speaker. If the lugs are different sizes, it might be easier to reverse the connections on the speaker input jack. You can also work your way back in the signal chain to any point that's convenient and reverse the signal leads on one side. It can be done in a cable, or inside your amp, but I would recommend doing it inside the speaker cabinet as it will keep things from getting confusing in the future if you change equipment. The phase of a speaker it determined by the wiring of the cabinet, the direction in which the voice coil of the speaker is wired and how the magnet it oriented. There's no standard between manufacturers - they're usually only consistent within their own lines. What you want is a particular waveform to cause all the cones to go out at the same time (rather than some in and some out). Phase relationship only matters when you're running multiple cabinets. So, you can reverse the phase of one of your cabinets and there are no implications when you use that cabinet alone. David Fung | ||
| palembic
Senior Member Username: palembic Post Number: 2535 Registered: 9-2002 |
Hey Dave! Thanks! The guy from the electronic part store will check th eoutputs with a kind of "measuring thing". I'll see what happens! Paul TBO | ||
| lbpesq
Senior Member Username: lbpesq Post Number: 2350 Registered: 7-2004 |
An easy way to check phase in a speaker is to touch the terminals of a 9v battery to the speaker terminals. Assuming the battery has juice, it will make the speaker cone travel, either out or in depending on polarity. (If the battery makes the speaker travel out, reversing the battery will make it travel in). Now check out the other speakers in the system the same way and wire accordingly. Bill, tgo |
