# Scan-speak 18W/8531G-00 - A subjective comparison



## durwood (Mar 7, 2007)

Technical Data differs slighlty from the T/S parameters, but here it is from Madisound



> TECHNICAL DATA:
> Sensitivity 2.83V/1M 87dB
> Free air resonance Fs 27.5 Hz
> DC resistance 5.8 ohm
> ...


Oh Scanspeak Revelators where have you been all my life? This will be my initial first impressions, only two days of listening so far. Well built as expected. The paper cone is somewhat interesting since the slits are actually glue points of the cone. There is already a foam gasket on the mounting ring of the basket. The voicecoil is open for venting, so use care to protect it from things falling inside there, just like the Seas RNX drivers. I haven’t tried debucking yet, and figured I could just pop them in my doors and go. Well they slightly rub on the windows so I will be either debucking or try spacing my window track out a hair. 

Anyway, continuing on….
All I have to compare to are my recent MBQuart QWD160 (6.5’s From the QSD216 set and my Seas L18’s in this car) Amplifier power was a mere 25-30W, source unit my carputer running a digital signal to the H701. These were only tested as a dedicated midbass.

The Revelators have very good presence. Listening to rock was a treat. The guitars sounded so beautiful, fairly thick but not overdone so it didn’t sound one bit muddy as my Quarts sounded at times. They very surprising efficient with 25-30W, but I believe it’s the paper cone that helps. I started with my crossover set at 80Hz, 24dB and they were quick, snappy, but not quite as snappy as the L18’s. It has been my experience with aluminum cone woofers that they have a snap that other materials don’t have, so I’m not surprised there, but I felt the revelators had a more well rounded full bodied sound. My L18's seemed to have more authority in the 80-100Hz range where the Revelators seemed better in the 60-80Hz region, but also continued to have good authority below 60Hz as well.

I decided to see what the rev’s could do, so I lowered the crossover point, first down to 71, then to 63, then to 56 and finally to 50 all at 24db/octave. Each time the revs performed great, they kept extending lower and lower without any dropout. I found the happy medium for me was 71Hz, it was a good balance of output and low end. They could play low, wow could they go low probably because it has one of the lowest FS I have seen out of a 7” driver at 27Hz. I think you shouldn’t have a problem running them lower with less power, but at 50Hz, or even 63 Hz they started reaching there limitations. Like I said the happy medium for me was 71Hz. I have to investigate though if the cone’s excursion was hitting the door panel, or it bottomed out, or if it was door panel resonance, but I think it could be my water guard baffles. I don’t have room for a baffle but there is a layer of Raammat and foam baffle decoupling (a PE foam speaker baffle cut in half and used as a water guard.) I was able to push the crossover on my sub as low as 31.5Hz @ 12db and the sub just fades away and only adds in that extra low end when needed. These blend perfectly with my sub, probably the best it’s ever blended. It’s a shame I am only using these for dedicated midbass drivers, I’d love to see them really shine in the midrange section.

A personal note:
Other drivers I would like to hear them against or I have considered as a dedicated midbass in a 3 way setup include the 7" Peerless SLS, Adire SF7, Adire Extremis, Usher 8945P, and the Seas Lotus or W18NX.


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## t3sn4f2 (Jan 3, 2007)

Nice review. Did you notice the extra 20 square cm of cone area with these compared to other 7". That might be the reason for that greater lower bass output, and they are only slightly bigger then the rest.


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## B&K (Sep 20, 2005)

Man I was there a week early. I would have loved to help you swap them out. Of course, I will be doing the same in a week or so but replacing Excels with the Rev's run 2way with a D2904.


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## durwood (Mar 7, 2007)

t3sn4f2 said:


> Nice review. Did you notice the extra 20 square cm of cone area with these compared to other 7". That might be the reason for that greater lower bass output, and they are only slightly bigger then the rest.


Yes I did notice the extra size. had to whip out the jigsaw to account for that.  'm not so sure though that the extra cone area really helped it play lower. I think there were other factors involved such as a higher VAS and a 10HZ difference in FS between the L18 and Rev.



B&K said:


> Man I was there a week early. I would have loved to help you swap them out. Of course, I will be doing the same in a week or so but replacing Excels with the Rev's run 2way with a D2904.


Sorry, if Madisound would have had them at boner price a week earlier at they would have been in there. I'd say they were pretty close to how your truck sounded with your CA18RNX as far as midbass output. I'd have to do a side by side though to figure out if they were playing lower than yours. YOu had some awesome midbass in there and it really had me wanting more. I did some TA/phase adjusting last week after hearing yours and was able to get the L18's to sound better than when you heard them. I just found npdangs review of them after I posted this and I couldn't agree with him more on the Rev's.


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## durwood (Mar 7, 2007)

Update:

I debucked the Scanspeak following the Dayton guide. I lightly/mediumly tapped the corner edges of shielding. Once the sound changed A grabbed firmly and pulled off the shield. Then I took a medium sized flathead screwdriver with a hammer, and tapped fairly hard on the edge between the rear plate and the debucking magnet. The first one came off in three pieces. The second one came off in one swoop. 

Sorry for the crappy cam pictures. All I had was my camera phone. 

EDIT: Disclaimer: Do this at your own risk!


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## npdang (Jul 29, 2005)

Yikes these aren't daytons! Please don't hit the shield. If you ruin the driver it's going to be very expensive to replace. 

It maybe a bit more labor intensive, but I firmly believe that cutting through the shield with a hacksaw or something similar is the safer route.


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## alphakenny1 (Dec 21, 2005)

whats the depth after you debucked them?


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## andthelam (Aug 9, 2006)

npdang said:


> Yikes these aren't daytons! Please don't hit the shield. If you ruin the driver it's going to be very expensive to replace.
> 
> It maybe a bit more labor intensive, but I firmly believe that cutting through the shield with a hacksaw or something similar is the safer route.


Would you just hacksaw down the middle? Where does one start?


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## durwood (Mar 7, 2007)

alphakenny1 said:


> whats the depth after you debucked them?


3" maybe a tad more.



npdang said:


> Yikes these aren't daytons! Please don't hit the shield. If you ruin the driver it's going to be very expensive to replace.
> 
> It maybe a bit more labor intensive, but I firmly believe that cutting through the shield with a hacksaw or something similar is the safer route.


I knew they weren't Daytons. I tried to figure out another way to use them in my car, but I couldn't relocate the window rail as I would have liked. Baffles were a no go otherwise I would have done that a long time ago. I took a chance...trust me I was very very VERY reluctant. The only thing I was worried about was demagnetizing the permanent magnets by hitting it or crackign the magnets. I really didn't have to tap it that hard and I didn't hit agaisnt the permenant magnet. My other option I was going to try was paint and gasket remover and just squirt a little in there through the back hole after plugging up the vent hole. What do you think about that method?

I would like to add, I laid the speaker face done on carpet and found the quickest way without much hitting was to tap along the rounded edge of the shield in a horizontal motion just slightly angled perpendicualr to the edge curve. You can see there wasn't alot of glue, I think less than the daytons although I have never debucked a dayton personally so I don't know. There was only a glue ring ont he debucking magnet top and bottom of it. Then I proped the speaker up on it's side on the carpet again (So it doesn't fall from a great height if you lose control) and rested the magnet against a piece of wood and used a smaller flathead, since the debucking magnet goes all the way to the edge of the backplate. It took some balancing but it worked ok.

What type of issues do you expect you happen by hitting the sheild? Just wacking the motor structure off or something else? I noted that the motor is attached to the basket via screws instead of welds like my Seas drivers.

I should have added the disclaimer: Do this at your own risk!


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## shinjohn (Feb 8, 2006)

FYI...

http://www.diymobileaudio.com/forum/showthread.php?t=11697

durwood, I think you are right on with the concern about demagnetization due to impact. I think N is furher worried about damaging the basket or motor structure. Any misalignment, skewing of the voice coil in the gap, etc... could be very problematic. If the motor is attached via screws only, even more reason to be careful to make sure things don't shift when the driver is hit.

However necessary for car-audio use, taking a chisel or screwdriver to a $200+ driver is a bit scary.


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## durwood (Mar 7, 2007)

I was anxious the whole time while doing it. Trust me I would have been freaking pissed if I damaged one. 

I took care not to hit anywhere near the actual permanent magnet. I think the basket is also glued tot he motor besides the screws, but either way you are right. I wasn't using a sledgehammer and I kept he driver on the floor so I couldn't drop it. I also braced it or supported it with a block of wood when standing it upright. MAybe make a temp jig if you are really worried. I think anyone takes a risk trying to debuck them. I would warn anyone trying the saw method to tape off the basket and pole piece so you don't get any metal shavings in there. But as far as the chisel/screwdriver part-you have to get that bucking magnet off somehow.


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## npdang (Jul 29, 2005)

Exactly. It's not that much more work to cut the shield off. I usually cut a little past halfway down since the bucking magnet is smaller. Take some pliers and open the shield up so you can stick your chisel through, and a very light tap at the glue joint and it falls off. You should be ok there since you're not putting a direct hit to the motor. There's just too many of those I screwed up my speaker by whacking on it threads


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## durwood (Mar 7, 2007)

True good point. After I saw all those damages Daytons- I guess I should have taken more care. I was lucky, but i did learn from some of their mistakes. It seemed a few of those were from people really hammering away and few from dropping/knocking them onto the floor.

Everyone go with the saw method but tape off or protect certain areas of the speaker.

FYI: Mine are fine from what I can tell. They are pounding away in my doors and I can roll my windows down now.


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## durwood (Mar 7, 2007)

npdang said:


> Exactly. It's not that much more work to cut the shield off. I usually cut a little past halfway down since the bucking magnet is smaller. Take some pliers and open the shield up so you can stick your chisel through, and a very light tap at the glue joint and it falls off. You should be ok there since you're not putting a direct hit to the motor. There's just too many of those I screwed up my speaker by whacking on it threads


What do you think about plugging the vent hole in the pole piece and spraying some gasket remover/paint stripper in there after instead of having to chisel?


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## npdang (Jul 29, 2005)

That sounds like a great idea, but I'm not that creative  Definitely make sure to tape everything up you don't want to get little metal pieces into the gap.

I think the chisel is ok because it takes such little force to get that bucking magnet off if you hit in the right spot... which is more into the bucking magnet and not directly into the motor.


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## durwood (Mar 7, 2007)

That is what I wanted to do but I forgot to grab some from work yesterday and I really needed to get it done. I got the idea from Werewolf when he brought in the chemical aspect in the Dayton thread. I wish I would have tried it. Maybe someone else will have to be the guinea pig.

Edit: Even better, I will spray some on the debuckign mags I already have removed and see if the glue comes loose. That way we will know, then all we have to worry about is if the fumes are bad or not.


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## B&K (Sep 20, 2005)

durwood said:


> Yes I did notice the extra size. had to whip out the jigsaw to account for that.  'm not so sure though that the extra cone area really helped it play lower. I think there were other factors involved such as a higher VAS and a 10HZ difference in FS between the L18 and Rev.
> 
> 
> 
> Sorry, if Madisound would have had them at boner price a week earlier at they would have been in there. I'd say they were pretty close to how your truck sounded with your CA18RNX as far as midbass output. I'd have to do a side by side though to figure out if they were playing lower than yours. YOu had some awesome midbass in there and it really had me wanting more. I did some TA/phase adjusting last week after hearing yours and was able to get the L18's to sound better than when you heard them. I just found npdangs review of them after I posted this and I couldn't agree with him more on the Rev's.


Right on. Thanks, I love the midbass!


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## durwood (Mar 7, 2007)

Better pictures of the debucking magnet and shield. You can see how much glue was used on the shield side and the backplate side. The backplate side had more glue then the shield side. I then sprayed the magnet with paint and gasket remover. 10-15 minutes later the glue wiped right off. If you cut the shield, and then can manage to spray the paint and gasket remover in there without it getting all over the speaker, (it's not quite pure liquid but similar to how spray glue comes out) this might be an easy way to remove the debucking magnet from the backplate. I did not try it on the speaker so that is at your own risk if you choose to try that method.


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## andthelam (Aug 9, 2006)

As for the shield, I was able to get a flathead through the hole in the shield cornered between the shield and the bucking magnet and a forceful twist which undid the glue that held them together, no banging needed. As for the the bucking maget, it looks like Ill need to.


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## andthelam (Aug 9, 2006)

Magnet came off quite easily w/ screwdriver a quick whack, just make sure you have it secure.

Very dumb question: Which side is pos and neg on these Rev's?


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## azngotskills (Feb 24, 2006)

andthelam said:


> Very dumb question: Which side is pos and neg on these Rev's?


It doesnt really matter, just make sure that they are the same with both sides initially. After that you can play with each mid by switching polarity/phase, or even both depending on what sounds better


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## BTA (Nov 5, 2005)

andthelam said:


> Magnet came off quite easily w/ screwdriver a quick whack, just make sure you have it secure.
> 
> Very dumb question: Which side is pos and neg on these Rev's?


If you have it sitting on a table with the cone facing up;

Left is +
Right is -

It's really hard to see, but the black piece just above the connectors there is a + and -

I marked the pos side with a sharpie to make it easier later.


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## kappa546 (Apr 11, 2005)

andthelam said:


> As for the shield, I was able to get a flathead through the hole in the shield cornered between the shield and the bucking magnet and a forceful twist which undid the glue that held them together, no banging needed. As for the the bucking maget, it looks like Ill need to.


the shield came off so easy doing this. took me 10 seconds and little effort to do both. good thinking


now the bucking magnet has proven a different story. i've hit it twice with no luck but dont really want to whack it harder. i only had it face down tho and not secure in any way. i'll try again when i can secure it better i guess.


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