ScanSpeak Revelator 13" subs

[sigbergaudio]

2 newbie things I'm finding confusing:

1. When I view frequency response of 12-15" sub drivers on manufacturers' pages (they usually say it's a sealed or vented box and specify volume), they all drop off sharply at about 50 Hz.

I've looked at this for the ScanSpeak driver, as well as SB Acoustics, B&C, BMS, Beyma, Sica, Dayton.

So to implement these drivers I would have to do massive EQ boosts in the low end? That seems bad.

What I mean is, on a commercial sub, say https://www.audioholics.com/subwoofer-reviews/monolith-13201d-thx-ultra/conclusion , the drop off occurs at a much more impressive ~20 Hz.

2. The ScanSpeak 32W has a resonance frequency of 18Hz. Does that mean I cannot have extension to say 16Hz (pipe organ lowest note), because it requires crossing the 18Hz Fs which will presumably sound unpleasant?

--

I'm not after massive SPL (my room is small-medium at 2200 cubic ft), but I want to have low frequency extension to cover all material in movies (including 10-20 Hz range). I know it's not audible but maybe possible to feel.

My goal is to make something comparable to the Monoprice Monolith 13” THX Ultra or Perlisten D12S.

1. In practice you will get room gain too, but yes some EQ will typically be required. The smaller the box, the more will be reuquired. But as long as you stay below xmax that isn't necessarily a problem.

2. No, it will work below the fs as well. But the higher the fs, the harder it will be to get it to play the lowest notes. 18hz is a very low fs. This driver will easily extend to 10hz in-room.

 

[voodooless]

Those manufacturers' measurements are free air measurements
Which means that if you stand in the middle of a meadow with the speaker in your hands it will measure like that from 1 meter

There are actually a lot of different “standards” out there. Some use a standardized baffle (IEC), some 1x1m baffle, some something else…. And some specify this, others don’t. Long story short: you can rarely use this data to compare bass extension.

 

[concorde1]

Thanks all very much.

1. I noticed on: https://www.scan-speak.dk/datasheet/pdf/32w-4878t00.pdf -- ScanSpeak actually recommends 129 Litre box for vented box.

2. As an exercise to try to understand the topic better, I used WinISD to try a few different drivers in sealed boxes (B&C 12TBX100 ; BMS 12N804 ; ScanSpeak 32W/4878T00).

The B&C and BMS both have -3dB at over 100Hz in sealed box at 50L. Also weirdly WinISD initially suggested boxes for them respectively ~14L and ~6L (way too small).

The ScanSpeak gave a more sensible suggested ~54L and has a -3dB of a bit over 40Hz.

3. I entered ScanSpeak 32W/4878T00 again but with 2x ScanSpeak 30W Passive Radiators in WinISD. I got a much more favourable response of -3dB at about 23Hz, in the ScanSpeak suggested 129L box.

More newbie questions:
What is going on with sealed boxes? Wouldn't someone building a 12" sealed sub would expect -3dB in the 20-30 Hz range? Increasing the box size only made the -3dB frequency even higher.

What is going on with those BMS and B&C drivers being 100+ Hz? They're advertised as "subwoofer" drivers (at least the B&C is definitely) so surely I'm doing something wrong.

I was considering the BMS and B&C because they apparently make good drivers, and currently a NZ distributor has a sale on B&C drivers.

Drivers: I think anything over 13" would be overdoing it for my small-medium room. I want a top end 12-13" driver and couple of passive radiators. I could spend big on the ScanSpeak Revelator's (which people are saying overpriced, I do hear) and it would still be a lot cheaper than buying completed subs I think. Because as I say, completed subs are mostly priced up heavily in my location.

If I want the bass as low as possible, flat down to 20Hz, what 12-13" drivers are the best?
And if possible, meaningful sub-20Hz response.

Alternative: I could change to tower version of my speakers (March Audio Ukkonen) and forget subs. But I understand with subs you get the benefit of positioning to even out response of the bass; with speakers you're somewhat stuck.

 

[sigbergaudio]

The B&C and BMC drivers are bass drivers rather than subwoofer drivers.

The Scan-Speak will need some light EQ to go lower in a small sealed box. Also remember that you get a lot of room gain. It will go flat to 20hz in-room no problem. You don't need it to go flat to 20hz in free air to do the same in-room.

 

[Waxx]

You need to look at more than fs to know what a driver can do, and sealed will always be harder to tune low without eq. That said i use a Scanspeak 26W8534G00 in a sealed and even without eq it goes to 32Hz in a 77L sealed cabinet. Most modern subwoofer that you buy in stores have extensive eq in their system build in to go that low. the B&C and BMS are low QTS drivers, so not really fit for sealed to go low. And they are more ment as bass drivers (80-300Hz) than subwoofers like said.

But with what you want, you run into the Hoffman iron law. You want loud, low and small, and that is not possible, certainly without eq. You need to choose two factors of that and compromise the third, that is just physics. There is no way arround it.

The best drivers to go low sealed are actually the Dayton RSS and UM series subwoofers, that are tuned to do that. The Dayton Audio UM12-22 or RSS315 are more fit. Or maybe the Wavecor SW312WA04/06, that is also used a lot for low going sealed subwoofers. And you also got the expensive and almost unobtainable (long lead time) Acoustic Elegance IB series.

 

[ppataki]

Just for the sake of experiment @concorde1

The biggest sealed box size for the ScanSpeak 32W is around 66 liters (this is where it will reach a Qtc value = 0.5 critical damping and that is where it will require the least amp power to drive it to xmax)

Max power will be 250W then (you see in the graph below that xmax ends at 20Hz in this case)

In this case this will yield almost 101dB SPL at 1 meter

To summarize: 700 EUR for the 32W in a 66 liter box and an amp with 250W power
(note: if you need a smaller cabinet, you can put it in a 23 liter sealed box too but then you will need 830W! power to reach xmax at 20Hz)

Now let's suppose that I buy low Qts PA drivers, namely the Beyma 15WR400 and put two of those in a sealed DOS config
In a 66 liter sealed box those will produce 99dB SPL at 1 meter at 20Hz (so only <2dB less then the 32W)

And to reach xmax you can drive them with 900W max and then you will get 104.6dB at 20Hz at 1 meter

To summarize: 350 EUR for two 15" Beyma drivers in a same size cabinet driven at 250W losing 2dB of SPL or driving it with a beefier amp gaining more SPL vs the 32W

A few notes:
- notice the cone displacement curve in case of the 32W vs the Beyma - usually lower cone travel results in lower distortion too
- for the Beyma (or any other PA driver) you will probably need a low shelf filter depending on your room gain

 

[TheBatsEar]

I want to build 2 subwoofers

I used this MDF and gave the subwoofer to a friend who handles it rough. It still looks great.
You don't have to be a magician with paint or veneer that way

I would pick a better suited driver today, but the build itself was easy enough, came to 220€ or so.
I used scrap wood cubes in the corners to screw everything together, only the bottom has visible screws. Use wood glue on the inside in copious amounts to give it more stability and keep it sealed.

 

[voodooless]

Just for the sake of experiment @concorde1

The biggest sealed box size for the ScanSpeak 32W is around 66 liters (this is where it will reach a Qtc value = 0.5 critical damping and that is where it will require the least amp power to drive it to xmax)

Max power will be 250W then (you see in the graph below that xmax ends at 20Hz in this case)

View attachment 310500

In this case this will yield almost 101dB SPL at 1 meter

View attachment 310525

To summarize: 700 EUR for the 32W in a 66 liter box and an amp with 250W power
(note: if you need a smaller cabinet, you can put it in a 23 liter sealed box too but then you will need 830W! power to reach xmax at 20Hz)

Now let's suppose that I buy low Qts PA drivers, namely the Beyma 15WR400 and put two of those in a sealed DOS config
In a 66 liter sealed box those will produce 99dB SPL at 1 meter at 20Hz (so only <2dB less then the 32W)

View attachment 310503

And to reach xmax you can drive them with 900W max and then you will get 104.6dB at 20Hz at 1 meter

View attachment 310504


View attachment 310505

To summarize: 350 EUR for two 15" Beyma drivers in a same size cabinet driven at 250W losing 2dB of SPL or driving it with a beefier amp gaining more SPL vs the 32W

A few notes:
- notice the cone displacement curve in case of the 32W vs the Beyma - usually lower cone travel results in lower distortion too
- for the Beyma (or any other PA driver) you will probably need a low shelf filter depending on your room gain

Excursion and surface area (displacement) determine the max SPL in a sealed box, the rest is just about efficiency.

 

[earik]

I used this driver as part of my Pandemic project:

Sorry, only have the pic with the grille attached to show at the moment. But it's a 4-way using two 6.5" Purifi woofers and a Bliesma T25B tweeter. The 32W takes over at around 225hz. It's around a 45-50L space, sealed, and has some boost on the low end. This sub is super articulate, has low distortion, and sounds amazing for all kinds of music.

To the OP: I'd take some of the negative comments about this driver with a grain of salt. Yes, there are more budget friendly options out there, but to be fair, there are also quite a few drivers that cost a lot more than this one. And unless someone has ACTUALLY used the driver and listened to it, it's hard for me to believe that they really can give you an accurate review. There was another guy here who built speakers with this and liked it, and I'm a second voice from another user who loves mine. As long as you are comfortable with the price, I'd say go for it. I don't think you'll be disappointed. They're incredible drivers.

 

[Salt]

Hmm,
Nice refrigerator design.
Any more insights?

 

[earik]

Hmm,
Nice refrigerator design.
Any more insights?

LOL. Yeah, blue monkey coffins. High WAF on that design choice, especially the blue part. But after she heard them, she begrudgingly let them stay for the SQ.

 

[Palmspar]

I used the Scan Speak 12 inch discovery drivers for a closed 60 liter dual opposed subwoofer with Hypex FA501 amp.
The sub looks a lot like the Arendal 1723 2S, but smaller in al directions.
It sounds great tuned with HFD @ 22hz+-3db, the SVS SB2000 has 23hz+-3db in REW.
For fun i test a single driver in the same 60 liter box, it tuned easy to 15hz+-3db with little low freq boost.

 

[concorde1]

I went against some of the recommendations and bought a couple of the Scan-Speak Revelator 13" drivers for a very good price.

Am going to build ported to get down to 20 Hz.

Will be using a sub amplifier on my desk - not plate amps.

Will probably use a MiniDSP Flex for DSP.