New-to-me equipment question

wildthing792

wildthing792

Audiophyte
#1
Hello -
My Brother-in-Law is an audiophile gave me some of his equipment because he's bed-ridden and can't go downstairs to his basement and enjoy it anymore. I'd like to know if it can be easily incorporated into my current setup.
He gave me:
- 2x Classe monoblock amplifiers (I think they're CAM-350s)
- 2x Original Meadowlark Blue Heron speakers (no model#, see attached pics)
In his setup, each speaker had it's own amp. I tried getting his receiver, but he gave that and his 18" sub-woofer to his brother.

My setup:
- Receiver: Denon AVR-1712
- Speakers: Klipsch 5.1 surround set

I'd like to know if this will work with my current setup. If it won't, what will I need to add/replace to make it work. I'm trying to do this on a budget. If it will work as-is, great, I can look into upgrading other components as time and money allow, but I'd really like to get them hooked up asap.

Thank you in advance.
WT
 

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Swerd

Swerd

Audioholic Spartan
Ratings
4,508 11 2
#2
It seems your brother-in-law gave you some very good stuff. It's too bad he's not well enough to enjoy them.

I've never heard the Meadowlark Blue Heron speakers, but they have a very good reputation. About 20 years ago, they sold for roughly $9,000 per pair. Here's a review (try to ignore the breathless hyperbole); it's clear the reviewer liked them:
http://www.enjoythemusic.com/magazine/equipment/0402/meadowlarkheron.htm

The Blue Herons are rated as very sensitive speakers, 90dB/W/m (90 dB when driven at 1 watt, measured 1 meter away),but are also 4 ohm speakers. If correct (sensitivity numbers are often exaggerated by speaker makers),a sensitivity of 90 dB means it won't take Herculean power to drive them. However, the amp must be stable at 4 ohms – more of a challenge than a speaker with 8 ohm impedance.

The reviewer said that amps with as little as 45 wpc was enough amp power for those speakers:

I am pleased to report that the BHs perform very well with all three amplifier options. The mighty VTL 750s, of course, will drive virtually anything, even in their half-power (350 watts each) triode setting. But the 45-watt Tiny Triodes, imported from the second system into the main listening room, also drive the BHs to soul-satisfying volumes, with excellent bass control. (VTL amps are designed with solid-state rectification and optimized for a 5-ohm load, so the BHs' 4ohm impedance poses no problem for them.​

The Classe CM-350 monoblock amps were also very expensive, $7,000 per pair in 2001. They're built like a tank and no doubt, perform very well.
https://www.stereophile.com/content/class233-cam-350-monoblock-power-amplifier-specifications
Apparently, they are extremely powerful, 350 watts each with an 8 ohm load, and 700 watts with a 4 ohm load. I wonder if they weren't overkill for those Blue Herons.

Your Denon AVR-1712 is rated at 90 or 125 wpc when driving 2 channels with an 8 ohm load.
https://usa.denon.com/us/product/hometheater/receivers/avr1712 . The specifications download from Denon confusingly claims either 90 or 125 wpc, I couldn't tell which. This receiver probably has enough power to drive the Blue Herons, but I'd start at low volume and proceed to higher volumes carefully. If their impedance really is too low for the Denon, it will probably kick into protection mode, I hope.

Your AVR cannot work as a pre-amp for the Classe amps. To do that , you would need an AVR with pre-amp output jacks, such as the Denon AVR-X3400H.

Unfortunately, both Meadowlark and Classe are no longer in business. But the speakers and amps should have a long life. I hope you enjoy them.
 
Last edited:
TLS Guy

TLS Guy

Audioholic Slumlord
Ratings
7,339 17 25
#3
Well this is the deal.

The speakers are well thought of. Unfortunately you have the original Heron speakers and not the Heron 2.

Your speakers have the Audax gas filled tweeter. The gas is actually air. However the air leaks out in all cases as far as I can tell. The tweeters develop wrinkles in the membrane and loose output and stop working.

Moca Audio in France can restore them and add a valve so you can add air, but you have to remove the tweeter to do it.

Because of this problem Meadowlark switched to using a Scanspeak ring radiator tweeters for the Heron 2. However the crossover has to be modified and the driving transformer removed.

There are details here about the Meadowlark leak problem.

I know this might all sound intimidating, but I strongly encourage you to restore his speakers or convert them to the 2 version. Probably the later is more sensible and if you are handy something you could do yourself. These speakers will be far above what you have now.

I would definitely encourage you to drive those speakers from the Classe mono block and not a receiver.
In your situation a receiver with preouts is probably your best solution. Your other option is more expensive and would require an AV preamp and amps to drive your other three speakers.

Apparently fixing the speakers is not expensive. I think Marco Chauveau charges about 60 Euro to fix the tweeters. You will have to ask him about which Scanspeak ring radiator tweeter and the crossover mod if you want to go that route.

You are a lucky guy and have an interesting project well worth trouble.
 
wildthing792

wildthing792

Audiophyte
#4
Thank you for the information. I'll look into upgrading my receiver. I'm assuming they're the original Heron speakers. I'll look for some model information on them later.
 
TLS Guy

TLS Guy

Audioholic Slumlord
Ratings
7,339 17 25
#5
Thank you for the information. I'll look into upgrading my receiver. I'm assuming they're the original Heron speakers. I'll look for some model information on them later.
I can tell from your picture of them that they are the original Herons with the gas filled Audax piezo tweeter. They are shown in your picture clear as day. Yours are NOT Heron 2s for sure.
 
wildthing792

wildthing792

Audiophyte
#6
I can tell from your picture of them that they are the original Herons with the gas filled Audax piezo tweeter. They are shown in your picture clear as day. Yours are NOT Heron 2s for sure.
Ther pic is one I grabbed from a website, not the ones I have. I was at work when I originally posted. I'll grab a couple pics and post them later.
 
TLS Guy

TLS Guy

Audioholic Slumlord
Ratings
7,339 17 25
#8
Ok. Here are pics of what I have. I'm guessing you're right about the speakers.
I completely forgot about the pre-amp he gave me. It's a Chord CPA 3200.
Thanks again for your help!
Those speakers have the Audax gas filled piezo tweeters. They are not Blue Heron 2s. I can also tell from your pictures that the tweeters are in very bad shape. So those speakers are not currently in working order.

So you need to send the tweeters to France to have them restored or modified. Alternatively you can convert the speakers to the 2 version. That is probably what I would do, but the choice is yours.

That Chord is a really high quality preamp. Properly restored that would be a spectacular sounding rig. It is well worth putting effort and resources into.
 
wildthing792

wildthing792

Audiophyte
#9
Those speakers have the Audax gas filled piezo tweeters. They are not Blue Heron 2s. I can also tell from your pictures that the tweeters are in very bad shape. So those speakers are not currently in working order.

So you need to send the tweeters to France to have them restored or modified. Alternatively you can convert the speakers to the 2 version. That is probably what I would do, but the choice is yours.

That Chord is a really high quality preamp. Properly restored that would be a spectacular sounding rig. It is well worth putting effort and resources into.
Thank you again for your help. I'll look into getting those tweeters fixed or replaced, then getting it all set up in my house.
 
KEW

KEW

Audioholic Warlord
Ratings
4,614 22 4
#10
TLSGuy has addressed your speakers.
While your brother-in-law did not give you the receiver, if he gave you the Chord pre-amp and the Classe amp along with the speakers, he gave you a complete two channel system.
Which Klipsch do you have?
I think while you are getting the speakers sorted, you should connect the Klipsch mains to the Chord and Classe and listen carefully to see if the sound is clear. I presume these are both analog units and there is a good chance they are in fine working order. However, it makes sense to test them out and if you have some uncertainties, find a good tech to evaluate them.
 
KEW

KEW

Audioholic Warlord
Ratings
4,614 22 4
#11
Depending on the layout of your home (and how much the TV is spoken for-wife and kids),you might consider leaving your current system in the TV/HT room, and setting up the gifted gear in another room for listening to music.
You can intermix the old gear with your new stuff (after getting a new AVR),but the Chord will have no role and you are not going to get a timbre match between your Klipsch center and Blue Heron mains!
 
TLS Guy

TLS Guy

Audioholic Slumlord
Ratings
7,339 17 25
#12
So, I have spent more hours then I should have on this problem. As always problems like this always turn out far more complicated than you hope.

So this is the essence of your speakers.

The bass section is a traditional reverse tapered transmission line. This makes it a rare animal. However it gives a bass accuracy quite unlike any other form of loading. For the size of the speaker bass extension is excellent.
F3 is 30 Hz. A TL properly designed rolls off only 12 db per octave, so this speaker will have usable good clean bass to 20 Hz.

Another unusual feature is that the mid range driver is also in a TL that is totally damped. I always thought I was the only one to have done that, now I find apparently not.

Now the speakers come from an era where a lot of people where using and experimenting with "simple" first order crossovers. This means that the drivers cut off very gradually only 6 db per octave. So for instance the tweeter crossover at 5 KHz is only down by another 6 db at 2,500 Hz. The object behind this was to preserve time and therefore phase coherence to try and create the so called time aligned and therefore minimal phase shift speakers. They were also referred to as transient perfect speakers.

At the time of your speakers and a bit before this had quite a following no only from your speaker's designer, Pat McGinty, but the likes of JIm Thiel especially and Dynaudio in Denmark. There were also others. I had my flirt with this also.

The problem is there are significant downsides. This part is important as it relates to your problem. The issue is a lot of driver overlap either side of the crossover and as a consequence a lot of power to the driver either side of the pass band. This is an especially serious problem for tweeters.

Now to your speaker the original BH speakers.

The tweeters are the Audax gas filled piezo tweeters. After lots of searching I have managed to find the original Audax spec. sheet.

Now if you look at the graphs you will note that the unit is really a super tweeter and only usable above 5 KHz.
You note apart from being a superb unit, that it naturally rolls off at your speakers 5KHz crossover point. In addition piezo tweeters tolerate a lot of out of band power. So it is easy to understand why this unit was selected.

The other thing shown on the spec sheet is the driving transformer and circuit. This will have to be removed if you plan on having these tweeters repaired and modified. I suspect they all fail as the designers forgot that gases slowly diffuse though thin membranes.

Now your speakers used Audax 3.5 mids with aerogel cones. Back in the day those drivers were actually very good. Unfortunately I can not find the spec sheet on that particular driver.

Now as to your second option, just changing the tweeter does not make it a BS2. The BS2 also uses a Scanspeak mid range. So to make it a BS2 that unit would also have to be changed but it is much bigger, so probably not possible as it has to fit in the small TL. Also since I can't find the specs on the Audax mid, I can't begin to guess at the crossover mods.

So that leaves the only option other than original tweeter repair to be replacing the tweeter.

Now the recommended replacement is this Scanspeak tweeter. The biggest issue with this has been tweeter burn out. This is because of the large amount of power sent to the tweeter below crossover because of the first order 6 db crossover. However the acoustic response of this tweeter makes it suitable.

Now I have found these speakers have a had a significant following in the UK. This is not surprising because of a fondness for transmission line speakers. So a UK site has recommended this Scanspeak tweeter as replacement. However I feel it does not roll off nearly fast enough at 5 KHz to make it a good replacement. I think it would adversely affect the sound significantly. However after removing the transformer and the high pass section of the crossover putting a 5.1 mfd cap in series with the tweeter would be all that is required according to my modelling.

I think the better choice though is the ring radiator tweeter and just not play the speakers too loud.

If you choose to use that tweeter then I calculate that after removing the transformer and high pass filter, then you need an 8.2 mfd cap plus a 1.5 ohm resistor in series with the tweeter, you need a 15 ohm resistor between the +ve and -ve terminals of the tweeter.

I actually think this would most likely work quite well as it is close to the response of the original.

If you want the speakers to sound exactly original then you need to contact MOCA France.

I expect you are going to have lots of questions after this, so I wait in trepidation. I have given you accurate information, as usual the web is awash with less than accurate information.
 
Kvn_Walker

Kvn_Walker

Full Audioholic
Ratings
143
#13
OP do you have a room that you can use as a dedicated 2-channel music room? What he gave you would be a damn near perfect music-only system once you got the tweeters repaired or swapped.

Also, what Klipsch do you have? The speakers you just got are going to have a significantly different sound signature than your current fronts.
 
wildthing792

wildthing792

Audiophyte
#14
TLS Guy - Thank you for your very detailed and in-depth reply to my question. I agree, there is a lot of inaccurate information on the web. I posted here hoping someone with more knowledge than I on the subject would be able to help. I am a duffer when it comes to sound systems, I like good sounding systems, but am not that knowledgeable when it comes to putting them together. :confused: I wish my B-I-L could help me, but he's not local and gets depressed talking about it.
When I have some time in the next week, I'll go over your response and post any questions I have on it.

Kvn_Walker - I live in a 100+ year old 4-square house so really don't have another room to dedicate as a listening room. The Klipsh speakers were a 5.1 surround sound boxed set (similar to the HDT-600) I picked up with my receiver in 2012. My living room where I want to set this up is 13x26. (see attached pic for basic room layout)
My thought was to use the BHs as fronts in the room's corners and move the Klipsch fronts to the side as surrounds.
 

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wildthing792

wildthing792

Audiophyte
#20
Hopefully, the guy has another system upstairs.
Sort of, he has a Sunfire receiver hooked up to some impressive sounding speakers in his upstairs den. Unfortunately, he's bedridden and doesn't get to enjoy even that room anymore.:(
 

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