A question for Jubilee owners

[Flevoman]

 

A question for Jubilee owners who use different amplifiers for the bass cabinet and K402 horn.
What method do you use to match the amplifiers' volumes to each other?
And what is the ratio?
Are the amplifiers set equally, or do you follow another rule of thumb, and why?

[Schu]

DSP... blend with 'ears'

[MMurg]

I'm using identical amps, so I don't have this issue.  The only way to do this correctly would be to either get the gain specifications from both manufacturers or have the proper equipment to measure the gain of each amp and adjust the gain in the DSP (or using the amp gain control if it has any) to compensate for the difference.  Since we are talking about amplifier outputs, I imagine you would need the proper gear to handle amplifier output level signals to do such a measurement.  I would not recommend trying this unless you know what you are doing and have the proper gear.

 

Other than that, this would be relatively inexpensive to try.  This is just an "off the top of my head" idea.  Get USB measurement microphone and download the REW software.  Set the mic up about 2 meters away from one speaker at ear level.  Try to have the speaker and the mic away from the room boundaries by a greater distance if possible.  Maybe put some sound absorbing material at the first reflection point on the floor between the speaker and mic.   Do a frequency sweeps about one or two octaves on either side of the crossover frequency and adjust the gain in the DSP until you get a flat response in that region.

[gigantic]

I multi-amp my three-way horns with 6 mono blocks. I balance the amps by measuring with a calibrated mic and REW, making adjustments to the DSP until they're set correctly.

 

[Flevoman]

@Schu This is how I used to do it in the beginning: adjusting the amplifier for the bass cabinets by ear, turning it up or down. For me, this method absolutely doesn't work. I kept fiddling with the volume knob for every different song 😏 and after a few songs I was totally lost. 

 

Thank you for your responses, I get the impression that you balance things using a more precise method than I do. And as I understand it, you also adjust the amplifiers to be exactly equivalent to each other.

 

Although I have REW and a calibrated USB measurement microphone, I seem to be doing things more loosely than you. (This method was recommended to me by KT88, as it best fits my level of knowledge.)

I connect amplifier 1 to the left speaker (including both the bass cabinet and the mid-horn) and amplifier 2 to the right speaker. Then I play pink noise and measure the decibels of both speakers individually using a dB meter, and adjust them to match. I then set the amplifier for the bass cabinets about 4 dB louder, as the DSpeaker anti-mode 2 filters out quite a bit of bass due to its acoustic corrections.

[KT88]

However, I did not describe the method with the measuring microphone, but rather the case that you don't have a measuring tool. You can get a rough approximation if the sound comes from the centre, provided that you have connected both basses and tweeters in a phase-correct manner. On the left, the one amp that will later be used for both basses, and on the right, the other amp that will then be used for the two basses. Of course, with tube amps, you also have to take into account which output tap is used for bass and treble. This at least gives you a rough orientation because your ear can distinguish more fairly between left, right and centre than when you have to match a bass with a tweeter by ear.

 

I didn't recommend the 4 dB louder in the bass, maybe it has to do with how DSpeaker works (which I don't know) and how much bass DSpeaker reduces to get a balance in the end.

 

This was perhaps a simple approach, and I found it sufficient for more than 14 years for my oen pleasure. However, it will never be completely accurate. When the fine-tuning between the bass and the K402 takes place, it ultimately depends on the timbre of an instrument, and we are really in the fine-tuning range. For example, you can hear the unmistakable sound of a familiar saxophonist in good headphones. I had chosen the thick guitar sound of Wes Montgomery because it is composed of both the bass and the K402. I've known Wes's tone for 50 years and I play a Gibson L5 myself. You hear it through your headphones and then through the Jubilee, so you can fine-tune whether it matches the sound of Wes Montgomery.

 

A good friend described a much more accurate method when I asked him for help. You may remember that I forwarded it to you. Honestly, it's not as difficult as it sounds. Read it two or three times and follow the steps. You don't need more than a voltage tester and sine tones from, for example, YouTube in the range of the acoustical cut-off frequency, approx. 500 Hz for the Jubilee.

By now you know how to operate the Yamaha DSP. That was the biggest hurdle at the beginning. Now you would be able to do it. And it is very accurate You can finally do the „soundcheck“ by ear with the sound of a familiar musician in the mid range spectrum as well

 

Here is what my buddy wrote:

 

 

Here's how I would do it:

1) Hook up everything as expected: source -> preamp -> xover -> amplifier -> speaker with the amplifiers on the tap settings you want to use, etc

 

2) find a way to get a sine tone generator at the source it preamp stage. Could be a CD with tones on it if you don't have a laptop.

 

3) I forget the acoustic xover frequency of the UJ, but find a tone near that frequency. Let's say 800Hz is the frequency.... You're going to play that 500Hz tone indefinitely and make sure nothing else can play (loop that channel, etc).

 

4) you're going to bypass all the processing in the DSP so that a full signal goes to both tweeter and woofer. This is why it's important to make sure you don't send a low frequency signal to the tweeter. Keeping the volume low should help too.

 

You need to remove any gain adjustment in the xover too. 0dB gain through the unit with no filters or other gain stages active.

 

5) Take a voltmeter, put it into the Vrms or V AC mode. And measure the voltage at the output of each amplifier.

 

6) Adjust the gain of each amplifier until they all read the same voltage. 

If the individual amplifiers don't have fine adjustment, then you can use the DSP output gain for finer adjustment. If you use the DSP, then you need to keep track of the delta between amplifiers and apply that difference to the stock settings.

 

7) Once you're done, you can turn the DSP filters back on and listen to music. 

What you've done here is measured the gain differences between the two amplifiers and applied the necessary adjustment after the xover.

One tricky thing here is that you've matched the output at a single frequency. When the tube amps try to match their output impedance with the tap settings, there is frequency variation due to the nonlinear impedance of the speaker. So you might still want to adjust by ear slightly.

 

Measuring the acoustic output is a better way to voice the speaker, but it would require an anechoic environment. It's nearly impossible to achieve the same gain accuracy inside a room.

I have definitely voiced speakers with only in room measurements, but it's always done by ear.... Using measurements to help identify the Q and slopes of the effects I'm trying to correct....and then I'm moving the mic and changing the time gating and filtering to be able to see what I'm hearing....and then adjust by ear once I can see my filter is lined up.

 

 

Make sure using this method of voltage measurement the speakers are ALWAYS. connected to the amp.

[Schu]

Not using your ears... is a complete waste of time.
the original question was VERY specific... it doesn't ask about using similar topology stacks.

 

if you are relying on a measurement device to determine for you is something sounds good, you may be able to teach a science class... but you're doing it wrong.

 

Learn to use your ears.

[KT88]

8 minutes ago, Schu said:

Not using your ears... is a complete waste of time.
the original question was VERY specific... it doesn't ask about using similar topology stacks.

 

if you are relying on a measurement device to determine for you is something sounds good, you may be able to teach a science class... but you're doing it wrong.

 

Learn to use your ears.

I basically agree with you, and I also write that I would always let my ear decide in the end. My friend also writes along these lines. But I have the impression that Melvin wants a stronger sense of security for a correct base, and a measurement can help there. However, I see it like my buddy that it's hopeless to use a measurement microphone in a normal living room. That only works in an anechoic chamber. That's why checking the AC output voltage on the amp is a good approach.

[mikebse2a3]

While there are other ways to accomplish this I’m going to suggest the following to minimize any mistakes or possible equipment issues.

 

* Important Note*: First it is absolutely not necessary to change any DSP settings to perform this test as described except when needing to adjust the DSP Output Level for amplifier gain matching later if needed.

 

Note (1): This method is using only one of the DSP LF Output Channels for a reference testing signal.

Note (2): Both amplifiers will be connected to a UJ LF Horn during their individual measurement testing.

Note (3): Any amplifiers with Input Gain Controls or amplifiers with Output Transformer Impedance Taps like on tube amplifier’s or McIntosh SS amplifiers *will require new measurements if any change is made later to them* in order to achieve proper amplifier level matching.

 

 

 

(1) Use REW to generate a 500Hz test signal.

FYI: My understanding is the acoustical crossover of the UJ is 500Hz in any Passive or DSP implementation by Roy.

 

(2) “Use only one of the (DSP LF Channel Output)” as your reference signal source for the amplifiers under test.

 

(3)  Connect the (DSP LF Channel Output used for reference) to -> [Amplifier (A)]’s Input and adjust the 500Hz test signal volume to a comfortable level and then measure [Amplifier (A)]’s “AC Output Voltage Value” and note it down for later reference comparison.

*IMPORTANT NOTE*: “Do Not” change the 500Hz test signal level after this because it is now our established reference signal test level.

 

(4) Now Connect the (DSP LF Channel Output used for reference) to -> [Amplifier (B)]’s Input and then measure [Amplifier (B)]’s Output AC Voltage and adjust { [Amplifier (B)]’s gain control if available} or the DSP Output Gain Level to achieve a “AC Output Voltage Value” to match with [Amplifier (A)]’s reference value reading. If using the DSP Output Gain Level for compensation the dB Level needed for matching will be the value you will need to use in the DSP Channels that this amplifier will be used with.

 

For example if Roy’s UJ programs requires the following when using matching amplifiers.

DSP LF Channel Level = 0db

DSP HF Channel Level = -3db

 

Now after testing we discover that [Amplifier (B)] required the DSP Output Gain to be adjusted to (-7db) to match [Amplifier (A)] test levels then this will need to be added to Roy’s program value and the change implemented in the channels using [Amplifier (B)] to maintain Roy’s program balance for the UJ’s LF Horn and HF Horn.

 

ie: If [Amplifier (B)] is used for the LF Channels then the DSP LF Channel Program Level will change to: (0dB)+(-7dB) = (-7dB) 

ie: If [Amplifier (B)] is used for the HF Channels then the DSP HF Channel Program Level will change to:  (-3dB)+(-7dB) = (-10dB)

 

 

miketn

 

 

[KT88]

Mike, thanks for your valuable input. It seems to be the clearer approach also to make it easier to implement.

Important is that it is done right.

 

[seti]

I use a an spl meter while I play white noise through the system and adjust the crossover gain controls till they are the same switching between amps. I have them marked with tape in case I move them.

Currently building amplifiers specifically for them the HF will be an all compactron SET amp 5-8wpc with a 6HJ5 not sure what will be LF.

 

[KT88]

8 hours ago, seti said:

I use a an spl meter while I play white noise through the system and adjust the crossover gain controls till they are the same switching between amps. I have them marked with tape in case I move them.

Currently building amplifiers specifically for them the HF will be an all compactron SET amp 5-8wpc with a 6HJ5 not sure what will be LF.

 

When you compare SPL, are you comparing the SPL of the bass to the K402, right? Can you compare the SPL of a low frequency to a higher frequency, or can you only compare SPL over the same sound spectrum? I really don't know. Does it have to do with your use of white noise because it distributes energy across the frequency band differently than pink noise?

[babadono]

@seti white noise? or pink? I would think white noise would lead one to attenuate the high frequency channel maybe more than it should be. I am no expert by any means but curious.

 

[Flevoman]

Good responses and tips. Thanks for the detailed explanation, and especially Mike's sounds like a very solid method to apply.

 

I had asked how other Jubilee users handle this out of pure curiosity how others handle this problem and to see if any interesting methods would be suggested. It's funny to hear that everyone has their own way of adjusting the amplifiers. I'm actually also curious to know which method Klipsch themselves recommend when you purchase the latest generation Jubilee. There must be plenty of Jubilee enthusiasts who have deep pockets but lack the necessary knowledge.

 

For now, my current method works best for me. And this is purely because I'm still experimenting and playing around with the UJ a lot. Using the decibel meter may not be the most accurate method, but combined with my ears, it works best for now. Once the dust settles and I reach the point where everything has found its place, I can apply a more serious method (like the one Mike suggested) to get everything properly adjusted.

 

[KT88]

I can't answer the question regarding the Heritage Jubilee. But I'm pretty sure it's recommended that you use the same amps or at least amps with the same input sensitivity and gain factor or the dealer can set it up at the customer's home.

[babadono]

Even "same" amps can have variability because of parts tolerance. How close does a said manufacturer match the channels? Can you hear it?

My 4 way UG Jube system has the ability to adjust gain/volume in at least 9 places in the chain. I try to keep them all at one setting except the main L/R volume, Sub volumes and final level control to the individual amps.

Still really curious to hear an answer about white vs. pink noise for system set up.

[rplace]

1 hour ago, babadono said:

Still really curious to hear an answer about white vs. pink noise for system set up.

 

https://www.sweetwater.com/insync/pink-noise-versus-white-noise/

 

This doesn't really say which is better for speaker set up, but tells you the difference. I get the feeling they are suggesting pink, based on the comments about the question.

 

I've got nothing to back it up, but my guy said white until I read it

[babadono]

I fear using white noise may cause this:

[babadono]

but yes @rplace I googled earlier and got the same SweetWater article.

[MisterVego]

There are many ways to do this.

 

 

I've done these 3 approaches and currently use #3.

 

1. Use amps that have matching gain outputs

2. If using a PEQ based DSP processor.  Make your measurements via REW, adjust PEQ's until the LF / HF are flat then adjust the DSP output until LF/HF match.

3. Move to a computer based DSP system utilizing a DSP filter generation program such as Audiolense or Acourate.   It will measure, adjust, level, EQ, time/phase align everything based on the target curve you provide.