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L-pad for tweeter level control?


rjp

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1 hour ago, CECAA850 said:
1 hour ago, wvu80 said:

Nobody uses L-pads these days.

I just got a set in the mail yesterday and will be using them soon.  Mids are way too hot on a pair of KP-2500's and this is the easiest and cheapest solution.

ALMOST nobody uses (snip!),,,

 

OK, SOME intelligent, better-than-average looking Forumites are using L-pads.  OK?  Sheesh!  :lol: 

 

When Chad creates a sub-forum for L-pad users due to the high demand, I will retract my assertions, issue private and public apologies,  and eat my electronic words.    But until then...:P

 

BTW, have you tried an electronic EQ yet?  (wvu80 ducks and runs) 

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38 minutes ago, rjp said:

Interesting you should mention this. I just measured the horns and I get 16 ohms at 1KHz and 8 ohms at 10KHz. There are no other frequency options in between on my LCR meter.

The pads I have are 8 Ohm.

 

What do you get if you just put an ohm-meter across the driver terminals with the wires disconnected from the drivers?

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23 minutes ago, CECAA850 said:

Where can you buy one new with a warranty for $30?

It comes built-in on the new AVR's.  You should try one, they're all the rage.  :emotion-21: 

 

And yes, I know you have a fancy 2-channel rig, but you can't tell me you don't have an AVR somewhere in the house.  For the TV, perhaps?  B)

+++

 

Edit:  Never mind, I just read your Signature quote.  You have Nelson Pass ACA Monoblocks in the GUEST BEDROOM for heaven's sake!

 

So when I can come for a visit?  :)

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Here is the crossover schematic. See what I mean by almost 4th order on the tweeter? What's up with the inductor in series with the resistor acress the horn? Can't be zobel unless horns are capacitive drivers, which I doubt.

 

Anyway, I couldn't find this schematic anywhere online so hopefully this will be usefull to others as well.

IMG_2377.JPG

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Here is a pic of the crossover. Nicely made! Even the LP cap is film type. Serious wireing too. I'm impressed. Note: the skinny little black wires are for the L pad I just installed. They are temporary so I can run them out the rear port for experimentation.

IMG_2368.JPG

Edited by rjp
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3 hours ago, raeggis said:

You must use 2pcs resistors to avoid frequency offset. 

IMG_20180501_125153.png

The driver's ohm value is its average value. Thus, you do not measure the driver's coil value.

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35 minutes ago, wvu80 said:

It comes built-in on the new AVR's.  You should try one, they're all the rage. 

My Anthem D2 has very sophisticated room correction software and I really like it BUT this is the 2 channel section.  I doubt there's many members here using an AVR in their dedicated 2 channel rigs.  Amps with built in PEQ's?  Sure.

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5 hours ago, mr clean said:

Get a schiit loki 4 band eq. It will not only work great on the 260 it will work on any speaker you use in the future! I use it on the rp280f speakers and it tames the highs and adds to the mids. Truly a great little item. It gives lots of control but not more than I want or need.

 

Mr Clean,

I just talked to my son and I'm going to borrow his Loki again and give it another try. I like how it is all analog circuitry and very high quality for a great price too. I just got the specs for where it's filters are placed from someone who did some measurements on it. Thanks for reminding me of this little device!

 

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2 hours ago, wvu80 said:

 

BTW, have you tried an electronic EQ yet?  (wvu80 ducks and runs) 

 

I tried the analog Loki 4 band as mentioned above, and the 31 band digital version in the ios app called SpotEQ. I only played with them for about an hour but they both seem to work well. The spotEQ app is really interesting. You can pretty much just drag your finger around the screen and put gain/cut anywhere in the spectrum. When you release your finger there is a sample point there and the EQ fills in the rest with a smooth curve. If you use Spotify it's worth a try. It allows for full Spotify access through the spotEQ app, but you give up the regular spotify GUI.

 

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1 hour ago, CECAA850 said:

I copied it to the crossover thread.

Thanks. It is good to know there is a place for collecting crossover schematics. I should go find this thread. Maybe they can tell me what the LR network across the horn is doing.

 

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2 minutes ago, rjp said:

 

I tried the analog Loki 4 band as mentioned above, and the 31 band digital version in the ios app called SpotEQ. I only played with them for about an hour but they both seem to work well. The spotEQ app is really interesting. You can pretty much just drag your finger around the screen and put gain/cut anywhere in the spectrum. When you release your finger there is a sample point there and the EQ fills in the rest with a smooth curve. If you use Spotify it's worth a try. It allows for full Spotify access through the spotEQ app, but you give up the regular spotify GUI.

 

The speakers I'm using the L-Pads in are fed from a pre-amp that also feeds another system.  I can't use an EQ in my source as it will affect the other speakers.

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2 hours ago, CECAA850 said:

What do you get if you just put an ohm-meter across the driver terminals with the wires disconnected from the drivers?

I don't know. I didn't measure the DC resistance. I should have. Next time I open them up I will.

 

Btw, is it normal that the equivalent series resistance of the horns decreases with increasing frequency (16RSE at 1KHz and 8RSE at 10KHz)? I would have guessed being inductive/resistive they would increase. I wonder if there are some L or C components mounted on the horn driver itself that I can't see from the back port.

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Hey, do you guys know about the "Tissue Paper Mod"? 

 

I thought it was a joke, but it really works. Just hanging one single Kleenex tissue across the entire horn with a piece of tape and Bam! instant harshness filter. The only problem is, well, it looks like a piece of tissue hanging in front of my tweeter ;)  I want to see my beautiful horn.

 

But seriously, try it if you haven't just for fun.  It is no joke.  From what I've read the method of attenuation is not absorption by the fibers but reflection back to the driver and cancellation. The basis for this assertion was that when the same tissue was placed over the microphone conducting the tests it had absolutely no effect and appeared acoustically transparent.

 

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3 hours ago, wdecho said:

I am a proponent of less is better especially when one goes to the trouble of purchasing expensive class A amplifiers. Why would want to throw an equalizer into the mix with all those op-amps twisting and twisting the sound. Defeats the purpose. I do not want any type of device including bass and treble controls on my preamplifier for the very same reason. And you are wrong about manufacturers using L-pads. Simple easy cheap solution for increasing or decreasing attenuation without effecting the basic simple circuit. Equalizers are for Bose 901's in playback.  

different strokes for different folks. If a piece of music needs more bass(to my ears on my speakers in my room) I turn up the bass. How many op amps do you think were in between the microphone at recording time and your speakers at playback time?

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27 minutes ago, rjp said:

Hey, do you guys know about the "Tissue Paper Mod"? 

 

I thought it was a joke, but it really works. Just hanging one single Kleenex tissue across the entire horn with a piece of tape and Bam! instant harshness filter. The only problem is, well, it looks like a piece of tissue hanging in front of my tweeter ;)  I want to see my beautiful horn.

 

But seriously, try it if you haven't just for fun.  It is no joke.  From what I've read the method of attenuation is not absorption by the fibers but reflection back to the driver and cancellation. The basis for this assertion was that when the same tissue was placed over the microphone conducting the tests it had absolutely no effect and appeared acoustically transparent.

 

 

 --- I often wondered the purpose of the toilet paper dispenser in PWKs anechoic chamber but never had the ballz to ask, thanks. KISS engineering never ceases to amaze me --- ?!

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