Scan Speak + Rane

After seeing several expensive high end speakers use the Scan Speak Revelator speaker components and noticing some lower priced electronic crossovers from famous names like Rane, I decided to built a set of speakers using these components.
I am one of the owners of small Audio Video installation company,so I felt if the we could possibly use them in a project once "tweaked" to satisfaction. Of course having a high end speaker at home is fun to play with any day of the week.
One of my installers is an enthusiastic DIY speaker builder,so he built the 2 cabinets
The drivers are the 7" Revelator mid woofer 18w-8531g and a the 2905/9700 Revelator tweeter.
I bought a 3 way crossover the SAC23 Rane. It could have been a 2 way,but I thought I might experiment with stereo woofers at some point.
The cabinet dimensions are around 2 liter as I recall.Brady made some sturdy sealed cabinets to around that size.
I had some old Adcom 535s to use as amps and a GTP 400 Adcom preamp to go along with them. I have a sonotube compound (2 Shivas)transmission line woofer from a previous experiment so I hooked it to the Summed woofer output of the Rane.
Long story short I used 1800hz for the crossover between the 2 Scan Speak drivers, the sound was very detailed. I used my old Audio Control RTA to check the response and it looked pretty flat,with a small dip at the crossover point.
I started to notice things in very familiars recordings for the first time using these revealing Revelators. The bass integration with the sub out was excellent as well.
I kept reading more about crossovers and noticed that "Zaph" in general liked to use the lowest tweeter crossover possible within the parameters of the components.
OK,the specs show the tweeter pretty flat to 500hz,so very carefully I lowered the crossover setting to 1000hz on the Rane. It has 24db per octave filters so it shouldn't allow much lower frequencies to get to the tweeter. Wow! the midrange got alot better! Even at high levels the sound is really clear and detailed. I found the blend between the drivers seemed better with a lower tweeter setting in relationship to the mid woofer. It sounds very neutral. Even old "Animals" and Beatles recordings are listenable.
Classical music is "Off the Hook" Violins have a "in the room' quality.
I am pretty darn naive on crossover design,but I must in the ballpark? The sound is too good to be way off. the tweeter seems to be tolerating the frequency range it is covering too.
I am thinking of ordering a Marchand kit and seeing if I can enhance the transparency with a audiophile style crossover? 1000hz seems to work pretty well.
Any recommendations or concerns from anyone before I continue on with the fun experiment? Thanks
Thanks
 

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ttan98

Member
2006-04-04 11:24 am
Melb
dallas said:

I am thinking of ordering a Marchand kit and seeing if I can enhance the transparency with a audiophile style crossover? 1000hz seems to work pretty well.
Any recommendations or concerns from anyone before I continue on with the fun experiment? Thanks
Thanks

Try digital x-over like the behringer dcx2496, about $250 each, it is very flexible and has lots of features.

I have one. You may surprised how different it sounds compared to an analog like Rane.
 

marchel

Member
2007-11-18 4:51 am
Based on your setup, I bet the sound lack mid bass or is mid forward , due to the lack of BSC, You'll gonna need an equalizer to raise the level to 6db from about 400hz and below that.

I suspect that the dip in the xo point is caused by the listening axis not coinciding with your microphone placement.

If I were to build an active system, I'd definitely go the digital proccessing route. Some proccessors from behrenger and dbx could do time alignment, auto eq, xo and so on , in one package.
 
Thanks for the replies! I know of the 2496,but I was trying to avoid digital. Too many Dto A conversions seem to add up to a fatiguing sound.In my experience anyway. Of course Meridian does it on the really high end.Very successfully.
At any rate I note that Baffle step compensation is available on the Marchand products as well. More of the high end analog approach.
I have not noticed any dips in response as was mentioned.
I will have to bring out the RTA again and take a look at the response.
 
After reading about Baffle step compensation, I wonder if that reflects the lower setting on the tweeter that (IMHO) produces the best sonic results with this combination?
The level control on the High output of the Rane allows some fine tuning. It is significantly less than the mid setting. Could this be compensating for the BSC effect?
Thanks
 

marchel

Member
2007-11-18 4:51 am
I've read that the behringer DSP arent really good sounding by audiophile standards, Dont know about the DBX drive rack DSP though, But I hope it sounds good , cause I'm kinda tempted to get one. asstd dbx drive rack The affordable ones :)

BSC affects the midrange and mid bass balance, If you have a 8" wide baffle , the 3 db point of the freq responce rise due to the effect of b.s. should be at around 565HZ. Therefore , the BSC in the marchand xo , should be adjustable or made specifically according to the width of the front baffle.
 
I am considering building a MTM version of this combination of drivers. Unfortunately everyone is out of the 18w/8531g. Bummer!
There are the 4ohm versions available. The 18w4531g.
It seems identical except for the impedance and Vas is 40 instead of 61.
I am tempted to try the 4 ohm version as I am connected directly to an amp anyway.
I am wondering what the Vas specification difference would change?
Any insight would be appreciated.Thanks
 
Dallas,

With high end drivers like the Scan Speak and your desire for a top notch speaker, you should consider having a design developed with the help of a talented non-professional or even a professional speaker designer. The magic in speaker design resides within the crossover. A passive crossover specific for your enclosure and drivers would be the best bet to your realization of a satisfying speaker vs. an on-going 'tweak' project with no pleasing end results. There are several individuals who can create an exceptional design for you for likely less money than the cost of a digital crossover box like the Behringer.

I have worked with one such speaker designer in the past and can highly recommend Rick Craig at www.selahaudio.com. I would not hesistate to contact him for advice on your drivers and deisgn requirements.

Jim
 

marchel

Member
2007-11-18 4:51 am
Dallas,

reducing the tweeter level alone will not compensate for the bs, it will still leave you with a hump in the midrange.

I agree that having passive XO is the best way to have great sound from the SS speakers, YOu can search the web for XO design for the drivers or you can have it professionally desinged.
 
I have been measuring the response with my RTA. It looks pretty darn flat. If I just play the tweeter it is really flat from 1000hz on up. Bringing in the woofer below 1000hz is not nearly as flat,but the room is playing a role I am sure. The overall sound quality is unbelievable!!
I could live with them as my own reference system. As mentioned any material oldies,classical jazz sound really good. Differences in recording quality is very obvious.
The only question is whether the tweeter will tolerate the lower crossover setting? It seems to handling it without any obvious strain or distortion.
I am not sure how a passive crossover could be better than an electronic version? Not an expert,but it would seem that connecting your amps directly to the speakers would be an improvement over a series of caps and coils clouding things up?
The research continues!
Thanks for the input
 
Dallas,

Those pesky coils and capacitors not only do the crossover function but they provide baffle step compensation for the woofer, equalization of the tweeter and woofer levels, notch out of band irregularities, correct the impedance values, and more. Your simple active crossover can not address any of those issues.

While your active crossover box can be paired with an equalization box to do those extra functions, you'll have a Rube Goldberg of wires and amps to achieve what those coils and caps can do. I really like active crossovers but my taste runs to something like the DEQX digital calibration processor which is the Swiss Army knife approach to digitally crossing over, speaker time/phase/amplitude equalization, and room correction.

Finally, those high dollar SS tweeters will not last long crossing at 1000 Hz. You could control the volume level and choose music that wouldn't stress the tweeter. But when you have the guys over to enjoy some loud music to showoff your new speakers (plus pair with some unknown music), then trouble lurks in your listening room.

Jim
 

ttan98

Member
2006-04-04 11:24 am
Melb
dallas said:

I am not sure how a passive crossover could be better than an electronic version? Not an expert,but it would seem that connecting your amps directly to the speakers would be an improvement over a series of caps and coils clouding things up?
The research continues!
Thanks for the input

I believe the excellent sound comes from driving the drivers using separate amps, ie biamping. I am doing the same thing except I use digital x-over.

I am now experimenting with passive components (designing a x-over) and test whether my hunch is correct. This way you can still achieve excellent sound. I am designing passive x-over myself and the parts are expensive some builders even use parts which are worth >$10 per capacitor or inductor some even more. A few mistakes/tweaks(there are bound to be, call tweaking, computer s/w design is never perfect) made in the x-over design I will be keep parts worth in excess of $10's to $100's, that are difficult to resell.

Digital/analog x-over is really worthwhile for experimenting(eg the x-over freq. that gives you best result), very versatile and relative cheap yet giving you excellent sound.

cheers, happy listening.
 
Since this thread was started, I have been trying a few different combinations. One of these, an MTM with SS 8531 midwoofers and 9900 SS tweeter. Madisound made a "leap" based passive crossover.
Great results, although certainly not as good as a more sophisticated crossover would produce. I have had good results using Audyssey Eq with any of these DIY speakers. Eliminates alot of small and larger frequency response issues

I recently saw and heard a loudspeaker at the CES show called YG. They use 2 SS 8530s and the SS6600 tweeter.
I thought it might be fun to "mimic" this design. They use a shallow waveguide on the tweeter. This puts the tweeter voice coil at the same distance and the woofer for improved phase alignment.
I ordered another "leap" design from Madisound and spent some time listening. It seems the waveguide increases the output of the tweeter in the main part of it's frequency response .The highest frequencys tend to roll off with the waveguide as well,but not too detrimental to the sound IMHO.
I (outboard) equalized the design with great success.Highly detailed with great imaging. I then found a YG review in Stereophile. Noting their crossover was 24db per octave at 1750 hz. I thought I could replicate that with the Rane Electronic crossover and the amps I used on my first design.
So I removed the Madisound crossover and hooked up the Electronic crossover and amps. Crossover set for 1750hz and 24db per octave
Wow! This is going to work out. Much more detail and dynamic sound,than with the passive crossover! I used my Audio Control RTA and a couple of Audio Control 1/3 octave equalizers (old school eq in this case, my Audyssey set up is on loan ) to flatten the sound. Most of the correction was room oriented, in the bass.
Still messing around,but this may be a keeper
Picture attached
 

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Now things are starting to work out. I bought a Marchand XM 9 crossover set for 1750hz. Same as the YG Anat. 24db per octave. This sounds WAY better than the Rane crossover (at the same crossover point and rolloff)I had been using. Much More detail and lower noise.
Having the tweeter recessed is definitely helping maintain phase alignment between the drivers as well
It sounds like a really really expensive speaker now.
Admittedly I am using "Audyssey" Eq to smooth out the final response.
Tweaking will continue,but I am closing on a super combination.
 
I am now using Hypex UCD amplifiers on the midwoofers. We are builidng another UCD amp for the tweeters as well. This really takes things to another level! Not really cheap,but as you step up in driver quality, any weak link tends to stand out.
Audyssey really puts it all together with their automated DSP Equalizer system. Corrects the speaker and room acoustic problems in one step
I would say over the next decade DSP based loudspeaker designs will dominate the industry. Any one try DEQX?