Experimenting with my Belles

[TubeHiFiNut]

I've temporarily (currently sitting on top) replaced the mid-horn on my Belles with an Emilar EH-500-2 horn with a Renkus Heinz SSD-3301 2" driver.

 

The change, to my ears, is a positive one.

 

The next thing I'd like to try is running the Belle bass with the Emilar as a 2-way speaker.

 

Some questions:

 

1. We'll get the dumb question out of the way first: Is there an easy (and reversible) way to modify the AA crossover to support this 2-way configuration? Easier and better to just use an outboard 2-way crossover?

 

2. What is the upper frequency response limit of the Belle woofer?

 

3. Any "words of wisdom" from anyone who has taken a similar path?

 

Thank you for any and all information and recommendations.

 

THFN 

Edited December 13, 2017 by TubeHiFiNut
Corrected driver model number.

[avguytx]

Well, being someone who just built a pair of Belle's from scratch, I can't offer much help.  I used new K-33-X woofers, Crites A-55G mids, and CT120 tweeters with Type AA crossovers using NOS Russian PIO capacitors and they sound amazing.  I have no desire to set anything on top of them now.    If I "were" to do something like that ever, I'd take apart the top section and rebuild side pieces and new grills to hold the mid horn versus sitting something on top.  Then they could be taller to hold whatever HF or MF/HF a person wanted.  

 

Before I'd modify a Type AA for something like that, I'd just build it from scratch using new parts.  But you'd need testing equipment to balance those out versus by ear.  The cutoff on that bass bin is around 500hz....which is where the K500 horn takes over.

[Chris A]

1 hour ago, TubeHiFiNut said:

1. We'll get the dumb question out of the way first: Is there an easy (and reversible) way to modify the AA crossover to support this 2-way configuration? Easier and better to just use an outboard 2-way crossover?

I wouldn't try to use a passive crossover unless you're pretty handy with using something like XSim (or similar crossover network analysis program).  The real remaining issue is that you can't time align the drivers to get a timbre-neutral loudspeaker using passives.  You can remove the tweeters from their top hats and place them on the top, aligned at the back of the cabinet with the midrange driver.  This is a BIG upgrade in soundstage.  That leaves the midrange/bass bin time alignment issue, but it's about 1/2 a wavelength misalignment at the center of the crossover interference band.

 

1 hour ago, TubeHiFiNut said:

2. What is the upper frequency response limit of the Belle woofer?

I wouldn't go higher than the stock 500 Hz due to the polar narrowing issue (the dual bass horn mouths create a "double slit" phased array that gets really narrow above 0.6 wavelength between the mouths).  You might push it to 600 Hz.  If you don't care about polars, then you can go as high as you want (and the bass bin can play), but this begins to sound not so good in a room.  Outside or in an extremely large room away from room or wall boundaries, it doesn't make much difference what the crossover frequency is in terms of hearing the effects of narrowing polars.

 

1 hour ago, TubeHiFiNut said:

3. Any "words of wisdom" from anyone who has taken a similar path?

Use an active crossover and Room EQ Wizard (REW) with a calibrated microphone to rebalance the loudspeaker. See the entry in this JubScala (and JuBelle) thread:

 

See this thread for how to use a calibrated microphone and REW to measure your hybrid Belles:

 

 

Chris

[TubeHiFiNut]

@avguytx and @Chris A - Thank you for your responses. Great information!

 

The Belles are an incredibly beautiful speaker and I won't do anything to permanently compromise that beauty.

 

If I stay with the Emilars, I'll figure out a way to remove the stock mid-horn and HF horn so the Emilar can fit in the top section.

 

Still reading and digesting all of the info @Chris A provided.

 

Thank you, again.

[Deang]

ftp://ftp.renkus-heinz.com/Legacy_Products/Datasheets_and_Drawings/Classic_RH_Drivers/SSD3301_data.pdf

 

Typical of most 2" compression drivers, you can see how fast the response drops after 8kHz, which means you have to go active - unless you have a very good software modeling program (like Leap) -- along with the measuring software and microphone (which Chris mentioned).

 

In the current situation, you really need to add a .40mH coil between Tap 4 of your autoformer and squawker positive.

[TubeHiFiNut]

23 minutes ago, Deang said:

ftp://ftp.renkus-heinz.com/Legacy_Products/Datasheets_and_Drawings/Classic_RH_Drivers/SSD3301_data.pdf

 

Typical of most 2" compression drivers, you can see how fast the response drops after 8kHz, which means you have to go active - unless you have a very good software modeling program (like Leap) -- along with the measuring software and microphone (which Chris mentioned).

 

In the current situation, you really need to add a .40mH coil between Tap 4 of your autoformer and squawker positive.

 

Thank you, @Deang

 

I also just got an a couple of adaptors, one that will match up to the stock Klipsch driver and another that will adapt my 1" Altec and Renkus Heinz drivers to the 2" Emilar horns.

 

Using the stock drivers with the stock crossovers should simplify things and give me a good baseline for the Emilar horn.

[Deang]

With the Type AA, there will be too much overlap, since there is nothing in the network to roll off the midrange. You need to add the recommended inductor. Capiche?

[TubeHiFiNut]

1 hour ago, Deang said:

With the Type AA, there will be too much overlap, since there is nothing in the network to roll off the midrange. You need to add the recommended inductor. Capiche?

With the Renkus Heinz drivers, understood.

 

But if I use the adapters with the stock Klipsch drivers?

[Deang]

Then you're fine. :-)