La Scala I's - Frequency Response?

[aaronhirsch]

Hi. I don't have a measurement mic. Can anyone tell me what the frequency response of a La Scala I from 1982 should be? A graph would be best, but a -3dB spec would be fine too... Thanks!

[hanksjim1]

Here's the Klipsch view...real world graphs depend quite a bit on room acoustics....I am sure other folks will chime in...

 

 

[zobsky]

From the graphs - Is the belle that much worse than the lascala in terms of bass response ? I thought they would have been pretty much the same in terms of low frequency response .

[OO1]

2 hours ago, zobsky said:

From the graphs - Is the belle that much worse than the lascala in terms of bass response ? I thought they would have been pretty much the same in terms of low frequency response .

 klipsch published this specs sheet in the mid 80's  ...I quote ....".Belle  has the same performance as the Lascala " .

 

https://assets.klipsch.com/files/Heresy-II-La-Scala-Belle-Klipsch-brochure-and-specs.pdf

[Islander]

45 Hz-17 KHz is the usual -3 or -4 dB rating for older La Scalas.

[JohnA]

The graph published by Mr. Paul in the Audio Engineering Society is this.  In my room, mine did not make it much above 14 kHz, but neither do my ears. 

 

[JMeader]

The above show a significant drop at around 300htz.

 

I just did a full blown REW and then a DIRAC test and in my room the biggest issue we had was the 300htz dip.

 

What have other done to counter this dip  or do you just live with it.

 

My sound is great no issues, great sound stage, but like a typical user can it be better

 

1987 La Scala's, all new Crites drivers with A4500 cross over, old Velodyne UDL 15 sub located center between speakers, room 17x22 with high ceilings

[mboxler]

5 hours ago, JMeader said:

What have other done to counter this dip  or do you just live with it.

 

 

If you have a 50uf or so capacitor place it across the woofer output terminals.  This will extend the bass and may fill in the gap.  You may need to reverse the polarity to the squawker and tweeter to compensate for the phase shift.

[JMeader]

Mboxler

 

would this be at the driver connects or at the crossover connects

 

I am not electrical guy so if at the crossover does it have to be soldered ???

 

 

a photo showing install would be great

 

Thanks

[mboxler]

1 hour ago, JMeader said:

Mboxler

 

would this be at the driver connects or at the crossover connects

 

I am not electrical guy so if at the crossover does it have to be soldered ???

 

 

a photo showing install would be great

 

Thanks

 

It doesn't matter, but at the crossover terminals is easiest.  I crimp the capacitor to a couple of spade connectors and attach them to the woofer output.  I grabbed a 15uf already crimped and attached it.  Hope this helps.

 

Mike

 

 

[babadono]

@mboxler your text says 50 but pic shows 15. Please clarify for anyone wanting to try. Thanks.

[mboxler]

21 minutes ago, babadono said:

@mboxler your text says 50 but pic shows 15. Please clarify for anyone wanting to try. Thanks.

 

I happened to have a 15uf already crimped, so I used it for illustration.   Sorry for the confusion.  Different values will yield different results.  I'd try anywhere from 33uf up to 68uf and see what measures/sounds best.  

 

If you don't have spade connectors, just bend each end of the capacitor wire into a half circle, wrap it around the screw, and tighten.  For testing I don't worry about the cosmetics 😎

 

Oh...non-polar electrolytic capacitors are fine here.  They are also smaller and cheaper!

[babadono]

Roger..different values of capacitance will do different things

[JMeader]

having no knowledge  of sources    would Parts Express be a good source

 

my cross overs have Sonic components is it beneficial to stay with same brands

 

Also you gave a range of 50-65 UF    would is the expected difference

 

Thanks

 

 

[OO1]

 oh ok

[mboxler]

On 6/28/2023 at 9:36 AM, JMeader said:

I just did a full blown REW and then a DIRAC test and in my room the biggest issue we had was the 300htz dip.

 

 

Before you buy anything, can you run REW on each driver by itself?  For the best results, you'll need an 8 ohm resistor across the tweeter output when measuring the squawker, and a 14-16 ohm resistor across the squawker output when measuring the tweeter.

 

That said, if you were to measure and post the woofer only response we might be able to determine the shunt capacitor value.  I have a couple of 82uf capacitors I can send you if it looks like they might work.

 

Mike

[mboxler]

To give you an idea of what a shunt capacitor does, I ran some rough plots of the voltage across the woofer.  

 

The green plot is a 2.5mh only.  

The purple plot is with a 25uf capacitor. 

The red is with a 50uf capacitor.

The blue is with a 75uf capacitor.

The "pink" is with a 100uf capacitor.

 

As you can see, the larger the capacitor, the more the voltage will increase, but the sooner the voltage will drop off.

Without a measurement, it will be hard to tell where you want the increased voltage.

 

Does that make sense?

 

Mike

 

 

[JMeader]

My problem is a significant dip starting at 200 htz  bottoming at 300 htz and gone by 400 htz

 

From the graph above any of the above "should" solve the problem

 

the 2.5 provides the widest coverage  the others only extend to say 800 htz  and then goes away.

 

Do you want to do the job and go away or provide an impact over the wider range

 

I truly appreciate your time in helping me understand this process.

 

Thanks again

 

 

[mboxler]

On 7/1/2023 at 9:38 AM, JMeader said:

My problem is a significant dip starting at 200 htz  bottoming at 300 htz and gone by 400 htz

 

From the graph above any of the above "should" solve the problem

 

the 2.5 provides the widest coverage  the others only extend to say 800 htz  and then goes away.

 

Do you want to do the job and go away or provide an impact over the wider range

 

I truly appreciate your time in helping me understand this process.

 

Thanks again

 

 

 

Sorry...I missed your post.  Took me a while to understand what you meant by "Do you want to do the job and go away or provide an impact over the wider range".

 

Ideally you want each driver to handle a specific frequency range.  In the case of your La Scala's...

 

Woofer 20hz to 400hz.

Squawker 400hz to 6000hz

Tweeter 6000hz and above.

 

There will be overlap around the crossover points as the following plots will show.

 

I don't own La Scala's, so these plots are for demonstration only.  The woofer simulations are courtesy of John Warren.

 

I plotted a couple of extremes.  A 2.5mh alone and a 2.5mh with a 100uf shunt capacitor.  The red plot (K55 response) is there to make my point.

 

Notice how the 100uf shunt capacitor boosts the SPL before it drops off?  Without it the SPL is dropping off too soon before the K55 can take over.  My thought is this may be causing the hole in your response.  Without measurements, I can't say this is what is happening, but for a few dollars it would be easy to find out.

 

  

 

 

[JMeader]

Thank You   I agree for a few bucks and a little time I can play

 

It will be a while before I can get to this as my wife has a few honey do's that will come first😀