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La Scala/doghouse: Was there a reason ...


Dave MacKay

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Hmmm ...

 

There have been arguments in favour of

  • no plug --- because the increase in (spatial, not sonic) volume is immaterial
  • reducing the bass bin's spatial volume --- which would support adding a plug
  • increasing the bass bin's spatial volume --- removing the access door and adding a riser or bass reflex mod

I've enjoyed the discussion, even if I don't understand acoustics well enough to draw a conclusion.

 

I figure that --- at some point ---  I'll make a plug and then see if I can detect any difference in how the La Scalas sound with and without it.

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1 hour ago, Dave MacKay said:

I'll make a plug and then see if I can detect any difference in how the La Scalas sound with and without it.

 

IMO, your time would be better spent experimenting with placement and/or room treatments.  That opinion is based on the subtle, but discernible differences observed after doing the djk bass reflex mod; I can’t imagine that any human could discern any difference based solely on the presence or absence of a plug. That said, it’s a hobby, and it’s your time spent.  If you experiment with or without plugs, please report your conclusions.

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I plan on trying this soon, just for S&G's if nothing else. I mean it's one of those 5 minute (one hour) jobs. If it works, great... if not, well then it's reversible and the cost to try is less than $20.  May even throw some sound deadener mat on the inside of the doghouse walls. (plan to lay it over some low tack shelf liner for easy removal) 

 

 I just wish I had a decent microphone to take some accurate measurements. I'd welcome others to try and maybe compare notes.

 

I'd have to recalculate the numbers, but I *think* that one piece of the Harbor Freight Anti-Fatigue Foam Mat set, and one of their kneeling pads (wedged between the magnet and the doghouse corner) will provide sufficient volume to reduce the doghouse by one third. I understand Carl Huff used a foam pillow, but the HF options are more convenient for me to try. 

 

 

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...I tried some acoustic foam in the doghouse, it KILLS the punch. Yet the new LS have a single piece thrown in. Probably to tame reflections.

 

I also seem to recall reading on here that the doghouse could actually be SMALLER, someone (probably Chris A) had run some simulations on it.

 

It is a folded horn with a definite lower limit as such, once you start playing with actual, or perceived volume it becomes a markedly less efficient direct radiator below the horn cutoff.

 

A digital signal processor is where it’s at, so I have come to understand. 

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...I tried some acoustic foam in the doghouse, it KILLS the punch.  

I'm not totally surprised that this may happen. I mean the frequency sweep captured by Carl Huff clearly shows the response being 'smoothed out' by lowering some peaks while raising some dips.  Does the type of foam make a difference or is all that matters is the amount of volume displacement?  I don't know. 

 

 

I've debated around and around in my head about going the DSP route. My challenge was/is needing at least nine amplifiers to run L/R and Center 3 way speakers. Then down the road if you upgrade your Home Theater amp, you'll need to find one that provides "pre-amp'" outputs to drive the other nine amplifiers being fed from the DSP unit.

 

Another issue I couldn't address is the probable 'lip sync' that would occur after the signal passes from 'pre amp' to DSP, to amplifier, to speaker while using the home theater. At least this is one of my fears. Not having a DSP unit to test makes it hard to know for certain.

 

In the end, as much as I like the idea of using DSP, using old school crossovers is probably going to be the best solution for me for listening to music and home theater. 

 

If I'm missing something, I'd love to be corrected before I lay out cash for more crossover components.  

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5 hours ago, Rockets said:

 

...I tried some acoustic foam in the doghouse, it KILLS the punch.  

I'm not totally surprised that this may happen. I mean the frequency sweep captured by Carl Huff clearly shows the response being 'smoothed out' by lowering some peaks while raising some dips.  Does the type of foam make a difference or is all that matters is the amount of volume displacement?  I don't know. 

 

 

I've debated around and around in my head about going the DSP route. My challenge was/is needing at least nine amplifiers to run L/R and Center 3 way speakers. Then down the road if you upgrade your Home Theater amp, you'll need to find one that provides "pre-amp'" outputs to drive the other nine amplifiers being fed from the DSP unit.

 

Another issue I couldn't address is the probable 'lip sync' that would occur after the signal passes from 'pre amp' to DSP, to amplifier, to speaker while using the home theater. At least this is one of my fears. Not having a DSP unit to test makes it hard to know for certain.

 

In the end, as much as I like the idea of using DSP, using old school crossovers is probably going to be the best solution for me for listening to music and home theater. 

 

If I'm missing something, I'd love to be corrected before I lay out cash for more crossover components.  

I have a basic decision process I go through with speakers and I have had a ton of Klipsch with the exception of KHorns, Belles,  and Jubes or anything past about 1990 except some newer pro gear. Space is not a problem and sound is everything so here is what I do. I make some basic changes to what I get to try if a new type of speaker to me. Recap of course and check the integrity of all drivers and in the last few years add a tweeter to it if it takes one..  If at that time I find the sound lacking I simply move on to something larger and more capable that does not have to have a bunch of tweaks and mods done to it. That is what led me to the pro side of Klipsch and for my taste if the speaker I have works as designed sans tons of tweaks and mods  and satisfies my sound needs I figure it does so more effortlessly and with more headroom and sounds more natural.

 

  My Super MWM's are what dragged me kicking and screaming into DSP because they had a 108" throat length and it made a significant improvement. Never have to get another crossover made if your system is worthy of bi or tri amping. You have no fears about lip synching as signals travel faster than you can hear and time allingment which does effect what you hear can be corrected. Plus room correction and on top of that you can set up versions specific to genres of music tuned to your desire and room and call them up when you want. My Xilica stores 30 presets.

 

 I still like the simplicity of passive crossovers and the KP-301's I am getting soon will retain theirs and sound good. On other speakers I have guys who claim they can put a freestanding tweeter on top of their speakers, La Scalas being the favorite for this, and time align to the mid horn that way. Don't get me wrong I love to tinker as anyone who had ever visited me can attest to but what I choose to listen to on a regular basis has to meet my standards. The amount of tinkering I do has gone way down and now I look for a healthy skeleton to flesh out. Can't make a wimp into Charles Atlas.

 

  On La Scalas specifically a graphical EQ will solve humps in sound and be much cheaper and easier to learn BY FAR. Bracing the side walls makes a BIG difference. Recaping and tweeter replacement also makes for notable gains in quality and if these simple fixes don't make you happy move on. In my opinion if you do not do something about the side walls you have left the most egregious sound offender in place to annoy you forever. You can make LS and LSI's sound really good the problem is bass output. Then you have to add a sub and go down that road. The skeleton can't lift up a lot of weight on it's own. Of course this is all personal and while there might be general consensus  about some things, speakers I like you may not. DSP can change anything though, within the inherent limits of your speaker, and is a very worthwhile tool to have. It is however a PITA to get started with and more amps and at least a Mini DSP HD plus a U Mike and then REW software and then time to learn to use the stuff.

 

  Also have you considered an amp with room correction built in?  If you like the sound quality it produces it is sure a lot less trouble than a separate  DSP and many here do just that.

 

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9 hours ago, Rockets said:

 

I've debated around and around in my head about going the DSP route. My challenge was/is needing at least nine amplifiers to run L/R and Center 3 way speakers. Then down the road if you upgrade your Home Theater amp, you'll need to find one that provides "pre-amp'" outputs to drive the other nine amplifiers being fed from the DSP unit.

 

I'd bet that you could leave part of the passive alone and let the passive deal with the tweeter/midrange and biamp from the woofer to the passive (verses triamp).

 

Triamping might be the best of the best, but I've always understood the biggest offender is between the woofer/midrange.

 

(shrugs shoulders)

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I don't want to hijack this thread, but one other alternative is the "manual' DSP method.  I'd only need three additional Chi-Fi amps to cover R/C/L speakers by using the White 4400 Equalizers that I already own for each speaker. 

 

Yeah...I know it's not exactly the same...

 

 

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On 9/2/2021 at 9:36 AM, Dave MacKay said:

Is there a reason why Klipsch didn't fit a "plug" to fill the cut-out that provides access to the woofer in the La Scala? I wondered if the cut-out was left for manufacturing convenience or if that void might be part of the acoustic path design. 

 

I'm wondering if it might be a good idea to fit a plug to fill the void and attach it to the access panel. This would provide a (more or less) smooth surface under the woofer, without impeding access to it. 

 

I didn't find anything related to this question when searching the forum. I'm sorry if it has been discussed already

 

 

 

doghouse-access-port.jpg

The 3/4 inch plug  would not improve the sound , however you can route the perimeter of the access port by 1/2 an inch and add a 1/2 inch plug which would fill the opening seamlessly

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7 hours ago, RandyH said:

The 3/4 inch plug  would not improve the sound , however you can route the perimeter of the access port by 1/2 an inch and add a 1/2 inch plug which would fill the opening seamlessly

I'm sorry, but I'm not clear on what you mean. Is it to enlarge the access panel opening by 1/2" on all sides and then fit a 1/2" thick (not 3/4" thick) plug to fill the enlarged opening? If so, why would one need to make the opening larger before filling it?

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1 hour ago, Dave MacKay said:

I'm sorry, but I'm not clear on what you mean. Is it to enlarge the access panel opening by 1/2" on all sides and then fit a 1/2" thick (not 3/4" thick) plug to fill the enlarged opening? If so, why would one need to make the opening larger before filling it?

Currently Access to the woofer is from a cover on the bottom of the LaScalas , if you want to do away with that cover ,route 1/2 inch around the opening  in order for  a smaller cover to screw into the recessed area -

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8 minutes ago, RandyH said:

however I really think that this is what you need - this was designed by  @Full Range  over 12 years ago , basically a bass reflex mod 

 



Thanks for the mention 

I’m not sure about who actually designed the lower bass cabinet for the La Scala 

However what I do know is - the original build on my speakers was done by member @sootshe 

 

For my part I actually measured the bass cabinet and uploaded those measurements for others to follow 

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OK, so I acquired a pair of LS a while back, and they had a "plug" in the doghouse, comprised of closed cell foam and carpeting, cut to the shape of the access port.  I have to say that I was sort of appalled at this junk, so  I never even cared about comparing it to stock.  I have done, and continue to do some interesting La Scala projects, but this type of "mod" is just dumb.  Sorry.

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Thank Full Range for helping to keep the history straight on the well now known mod. It can be found in the archives.

A LaScala with the mod was think in alerts here a couple months ago or less.

As for the bottom cover, never do away with it as for resale or, your own purpose if you go back to stock. If done at all.

Thanks!

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1 hour ago, RandyH said:

Currently Access to the woofer is from a cover on the bottom of the LaScalas , if you want to do away with that cover ,route 1/2 inch around the opening  in order for  a smaller cover to screw into the recessed area -

 

I don't believe that is what he is asking about. Anyway, you would weaken the cab by doing that.

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1 hour ago, RandyH said:

Currently Access to the woofer is from a cover on the bottom of the LaScalas , if you want to do away with that cover ,route 1/2 inch around the opening  in order for  a smaller cover to screw into the recessed area -

I am with you guys and I can't figure out what he means either.

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