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hethj7

Starting point for tuning factory RF amps

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hethj7

I know @shawndoggy has posted this before, but I can't find it.  What are good starting points to have the crossovers set to start tuning the sub, cabin, and tower amps?

And on the 400.4 running all the cabins - do you run it in 2 or 4 channel mode?  Is there any reason to really run different crossovers front to back on those given the open air environment and sub?  Below is the factory settings- sorry I hadn't cleaned off all the sticker residue.

59429148-3351-4E56-8BAA-82FFD4CE04AC_zps

 

 

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shawndoggy

2ch/4ch depends on how many RCAs you have coming in. If one pair, 2ch, if 2 pair, 4ch.  (it's 99.9999% 2ch)

Should be set high pass

crossovers at 80hz is a good rule of thumb (looks like it's already set that way)

gains appear to be at min., so you can definitely get some more performance from them.  Set HU tone controls (bass, mid treble) flat, volume at 90% of max, put on some nickelback (c'mon we know you own some, but probably only because that's the tuning music that @philwsailz recommends) then turn up the gains till you hear distortion, then back them down till the distortion goes away.

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hethj7

Any advice on the towers with Rev 8's?  

 

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shawndoggy

high pass 100hz

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hethj7

What are the input level knobs for?

 

 

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shawndoggy

input level is the gain.

leave the punch eq knob all the way down.

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hethj7

Doh, I guess I knew that and got carried away staring at all the knobs and asking questions.  Thanks for the responses!

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MLA

Depending on what generation amps those are, they may have clip indicators. However, this does not mean anything more than thats the point the signal clips. 

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Nitrousbird

I tune with a SMD DD-1 (gains) and CC-1 (crossover).

I have discovered on multiple amps that the crossover printed may not be the actual crossover point.  CC-1 gets your crossovers right.

DD-1 can detect distortion at each point in your setup. If your source unit distorts at 80% volume, you are screwed if you tune it at 90%. Or if it is like my Alpine, it doesn't distort but needs tuned at or near max volume as the first 70% is about the same as the last 30%. 

Has been a very useful tool and takes some of the guess work out of tuning.  Was a very worthwhile purchase. 

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Fffrank
Just now, Nitrousbird said:

I tune with a SMD DD-1 (gains) and CC-1 (crossover).

 

Trade you some beer (via gift card) if you want to let me borrow these for a weekend??

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Lees23

Anyone ever tune with a multi-meter?  That's how I tuned my JL amps on my MC. They were way to "hot" when the boat was delivered.  The level inputs(not really gain, at least on JL amps) were set at 2/3rds from max and after tuning with a multimeter they were just under 1/2. It made a huge difference. The volume needed to be much louder but I still had plenty and it sounded better at high volume.  

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Slurpee

Sure. Works great. Though I prefer an oscilloscope. A DMM won't show when the signal is clipping or deformed. For instance you do not want to run the RF head unit above 32 or you'll get distortion at low frequencies. You'd never see it in a meter unless it had a THD measurement setting. 

When you're done tuning be sure to record everything and do the math to make sure you are not asking too much of the amp or pushing too much into a speaker. 

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David
3 hours ago, Lees23 said:

Anyone ever tune with a multi-meter?  That's how I tuned my JL amps on my MC. They were way to "hot" when the boat was delivered.  The level inputs(not really gain, at least on JL amps) were set at 2/3rds from max and after tuning with a multimeter they were just under 1/2. It made a huge difference. The volume needed to be much louder but I still had plenty and it sounded better at high volume.  

A multi-meter method is good if you already know the correct pre-clipping output voltage. JL Audio is one of the few that provide a true voltage number for every amplifier. Some one needs to have actually tested the amplifier in advance into a real current-consuming load and with a realistic supply voltage. Simply going by the rated output and applying that to a formula to find the output voltage could be 25 to 30% off.

Also, the multi-meter, DD-1, or O-scope methods only give you the maximum level. It would be extremely rare that the maximum level is the correct level on all channels of a properly gain-balanced system. This is just the first step. But certainly a good step.

Also, it's never advised to run a sine wave at full power into speakers. So when measuring the final stage, you have speakers disconnected. The voltage into a non-load high-impedance tool (meter, scope, distortion detector) will be different than the clipped voltage into a low-impedance high-current load. Also, you have no way of measuring speaker distortion. In the end, the best systems will use measuring tools but must be fine tuned by ear.     

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Slurpee

Or everything David said and you can use an app like this one to see the results on your speakers of your tuning.  That is if your ears are as bad as mine.

e-scope 3-in-1 by e-skett Corp.

i haven't tried this particular app. But I use similar methods with a proper mic and TrueRTA or REW software. 
 

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David
1 hour ago, Slurpee said:

Or everything David said and you can use an app like this one to see the results on your speakers of your tuning.  That is if your ears are as bad as mine.

e-scope 3-in-1 by e-skett Corp.

i haven't tried this particular app. But I use similar methods with a proper mic and TrueRTA or REW software. 
 

Keep in mind that within the context of not all, but most towboat systems, you have control over very few parameters. Zone to Zone Gain. Crossover Frequency. There's usually only one active crossover point with no passive adjustments. There are only a couple of zones to balance as in front/rear cockpit and sub/sats.

Slurpee, I suspect that your ears are very educated by now.

 

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hethj7

I tuned things this weekend and while it certainly is vastly improved, I'm not a pro at this.  

All tuning instructions say to tune with equalizer settings defeated.   I did this but after setting some of the EQ settings to my liking, noticed I'm getting the signal clip indicator lighting up on some tracks on my amps.   They didn't when all settings were flat.  What should I make of this?  

I should have taken pictures of where my gains ended up, but would you expect I'd have them turned up quite a bit on the stock amps?   I am probably at 75% or better on all 3 of them.   I assume this is because they aren't really proper amps for the speakers and I'm bit underpowered.  

Which brings me to my next issue - I get some whine in the speakers with the engines ruining.    Not terrible, but it is a bit annoying.  I've read other threads that say this is almost unavoidable with the WS420 and to try and calm it down, lower the gains.  However, with these amps, lower the gains greatly reduces what I can get out of the system.   Without massive amounts of effort or $ on new gear, I'm likely stuck with it the way it is.  (and yes, I think I have decent RCA's and power and ground for the 420 is pulled from the same block as the amps).  

 

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MLA
51 minutes ago, hethj7 said:

I am probably at 75% or better on all 3 of them.

 

51 minutes ago, hethj7 said:

I get some whine in the speakers with the engines ruining

Like Forrest Gump said, two peas in a pod. 

52 minutes ago, hethj7 said:

I assume this is because they aren't really proper amps for the speakers and I'm bit underpowered.  

Likely reflects the input level more than an amp thats rms is less than the speakers. The amp can only make what can make, regardless of its gain level. 

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hethj7

I can't change much about the input level at this point, right?  Factory BT to the WS420 to the amps is my setup.  

The WS manual mentions an input gain adjustment on it, but it appears to only be accessible under the top cover.  Is that right?  If I could increase the gain at the 420 and lower the amp gains, in theory that would help with the whine I think.  

 

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MLA

Its true that you cant change the output potential of the source unit. however adjustable EQ gains are a tool, even though they may only be accessible by removing a cover.  

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David
2 hours ago, hethj7 said:

I tuned things this weekend and while it certainly is vastly improved, I'm not a pro at this.  

All tuning instructions say to tune with equalizer settings defeated.   I did this but after setting some of the EQ settings to my liking, noticed I'm getting the signal clip indicator lighting up on some tracks on my amps.   They didn't when all settings were flat.  What should I make of this?  

I should have taken pictures of where my gains ended up, but would you expect I'd have them turned up quite a bit on the stock amps?   I am probably at 75% or better on all 3 of them.   I assume this is because they aren't really proper amps for the speakers and I'm bit underpowered.  

Which brings me to my next issue - I get some whine in the speakers with the engines ruining.    Not terrible, but it is a bit annoying.  I've read other threads that say this is almost unavoidable with the WS420 and to try and calm it down, lower the gains.  However, with these amps, lower the gains greatly reduces what I can get out of the system.   Without massive amounts of effort or $ on new gear, I'm likely stuck with it the way it is.  (and yes, I think I have decent RCA's and power and ground for the 420 is pulled from the same block as the amps).  

 

Related to the clipping. On a studio mixing panel if you add in EQ boost or add in additional tracks you have to adjust the master gain level down. Otherwise you invite clipping or saturation of the next stage. Your system, all systems, are the same. Any single EQ band boost is an overall increase in gain. This usually has to be offset unless the boost is minimal.

If all or even most EQ bands are boosted you are using an EQ incorrectly. You normally try to cut & boost equally for the best results. I know that EQs have large cut/boost ranges. But only a small portion of that range is useable...or should be used. A 6 dB boost may seem rather mild to you in respect to power because it impacts only a narrow frequency band, however, a 6 dB boost is 4 X power. A 10 dB boost is 10 X power.

There's much more to know about the proper use of an EQ but this addresses the clipping issue.

Onto the noise. Yes, some small increase in the noise floor, some small increase in 'hiss', is inevitable every time you add a gain stage (EQ, component). But motor noise is normally an installation issue and not something that is an automatic when adding the 420 EQ.     

 

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DrFred

I just reset my RF sub.  Several times.  I couldn't get at the set screws without pulling the amp.  Mine weren't quite as bad as yours but the slotted screw head on the pots were broke off. On my boat which has the identical amps, '13 VTX, mine sounded best with gain turned all the way down and crossover turned all the way down.  I mean counter clockwise to the end, the markings don't seem to line up with the pot position. Otherwise it boomed and rattled too much.  Once you do that you can gain up on the dashboard if you need to.  If your subwoofer is still over gained, muddy and boomy, then you can add 6 or 12 dB in line RCA attenuators. You'll need an extra short set of RCA cables to do that.  I did not check to see if there is an input attenuator on the amp that drives the small speakers.  Increasing the gain on that amp might work too.

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