Snell C/V crossover mods?? HELP!!

[LNeilB2]

Ok, here's the story. I have two pairs of speakers in my home right now. One is a pair of Snell Ds, the other a pair of Snell C/Vs. The C/V betters the D in a number of areas. The low end is vastly superior, with more weight, extension and control. The midrange is absolutely neutral. And the C/V will play at much higher levels without strain.
Both models use the exact same drivers. The D is a 3 way, with a 1" inch Audax titanium dome tweeter, a 5" midrange, an 8" woofer, and a rear firing tweeter in a 43 inch tall tower. The C/V adds an additional midrange with the tweeter sandwiched in an MTM array, and an additional 8" woofer in a 47 inch tall tower. Here are links for each model:

http://www.snellacoustics.com/typeCV.htm

http://www.snellacoustics.com/typeD.htm

There are two areas in which the D betters the C/V. There is more air at the top end, with more sheen on cymbals. And the sound stage seems to be deeper with the D, which may very well be related to the better HF output of the D that I just mentioned. As I previously mentioned, both speakers use identical drivers, in very similar cabinets. With that in mind, the only reason I can think of for the lack of air in the C/V would be the crossover. But I have also been told that an MTM array drastically affects (reduces) off-axis HF response. Are there crossover mods that I could make to address this issue, or does an MTM array, by nature, account for the difference I am hearing? After listening to the D it is clear that this tweeter is capable of sounding quite good.

Thanks for any help!

 

[ThomasW]

This basically gets the same response as your post regarding replacing the tweeters. Don't mess with these.

Generally speaking Snell makes excellent speakers. If you're unhappy sell them and build/buy something else. Or look at a better amp/pre-amp or sound source.

Why? As stated in the other thead, these things are a system and unless you have access to sophisticated design and measurent systems it's not possible to do justice to the design.

Also unless you have done a side by side comparison with the output levels match within 0.5db your impressions may not be correct. Frequently people listening to 2 speakers; one that has more bass output than the other, will think the speaker with the higher bass output is shy in the treble when it isn't. Do check to make sure you don't have damaged tweeters, but that I doubt.

BTW, MTM configs do not compromise HF dispersion

 

[LNeilB2]

Thanks Thomas!

 

[ThomasW]

Neil

Your welcome

BTW, I'm certainly not trying to discourage you from experimenting with speaker building. However I suggest making a new speaker from a kit or scratch design; as opposed to potentially messing up resale value of a good existing speaker.

 

[LNeilB2]

OK, but what about this idea?

A local high end audio dealer recommended that I upgrade the crossovers with same value, higher quality parts. Correct me if I'm wrong, but isn't this a safe upgrade? He knows a couple of experienced speaker builders that would do it for me. Any reason why I shouldn't try it?

 

[ThomasW]

Well I'd expect that the stock XOs have pretty good components given that the speakers are matched with in 0.5db of the Snell master reference system.

But obviously you are determined to do something to these speakers so.......

Caps are relatively easy to replace, but the inductors not only have a standard mh rating, but a DC resistance. I'm sure that the Snell engineers took the resistance into consideration when designing the XO. So it's important the the replacement inductors be a complete match.

Things to find out; are the upgraders going to match to this same spec? Can they modify one and let you evaluate the difference between it and the stock one? This is a loaded shootout because any increase in efficiency will be initially perceived as 'better' even if it's not.

One final thing, what is the rest of the system? Given the quality of the CV's, I'd suggest a long hard look at the rest of the system (the electronics) and the acoustics of the room before playing with the speakers. It may well be that upgrading one or more of the components will have the effect you are looking for.



[Edited by ThomasW on 10-25-2001 at 11:13 PM]

 

[LNeilB2]

The system isn't too shabby......

I'm using a Sonic Frontiers Line 1, Threshold S/300 amp, Sony ES transport with Audio Alchemy DDE 3.0 DAC & DTI jitter filter, Tara Labs Prime 1800 biwire cables and Axiom interconnects. I don't think the electronics are an issue because the same electronics drivig the Ds created a huge, airy soundstage. And placement is exactly the same. Perplexing!

 

[ThomasW]

Neil

You're right that's first class equipment, and yes it's is puzzling. Given the equipment, the only significant difference between the speakers should be the bass output.

Do you have access to any accurate measuring equipment? I'd be curious as to the measured output differences between the speakers in the FR range above 1Khz. If they measure the same, then it's a pyshco-acoustic phemomenon (more bass = sounding like less treble). However if the 'D' actually has more output, and that's what you like; it maybe the a simple exchange of the level matching resistors in the XO will do the job.