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Question High pass filter

tazzo1

Active Member
Hello all,

I'm getting a subwoofer built by Wilmslow Audio and am thinking of having it ported, but I read somewhere on the message boards that you need to have a high pass filter to protect the driver, hw would I fit this? Amp will be the Monacor SAM 300D and I'm using a stereo amp with low level connection.

Thanks
 

xxGBHxx

Well-known Member
Hello all,

I'm getting a subwoofer built by Wilmslow Audio and am thinking of having it ported, but I read somewhere on the message boards that you need to have a high pass filter to protect the driver, hw would I fit this? Amp will be the Monacor SAM 300D and I'm using a stereo amp with low level connection.

Thanks
It's done on the amp (usually) but your amp doesn't seem to have the capability. What are you getting built? That amp seems underpowered for a sub amp depending on what you're getting built and trying to drive.

G
 

tazzo1

Active Member
I'm getting a subwoofer built using the Scanspeak 28W 4878T00 driver, 45 litre size enclosure and the driver is 4 ohms so the amp has enough power. The amp is pretty good, I've used it before but I'm not sure whether to go for a ported or sealed design as ported goes lower but I'll only be using it for music.
 

xxGBHxx

Well-known Member
Never seen that driver before and not really an expert on driver specs I'd have to bow to other experts on the forum. ISTR that they're a very good company though.

If it's purely for music then sealed is generally preferred (though I only have ported). That said I've roughly thrown the specs into WInISD and that driver seems to prefer a ported enclosure. It's also eye wateringly expensive for a driver that size. I'm sure you could get as good for a lot less at that size or a lot better for the same money.

As I said I'm no expert so I'm guessing you know what you're doing more than I do!

G
 

tazzo1

Active Member
The 28W 4878T01 was recommended to me by Falcon Acoustics if I could stretch to it, however I went for the 4878T00 as it went lower but not as efficient. I'm looking to build a real quality subwoofer that can match expensive subs. I looked at the Seas L26ROY but I'm looking to aim higher. Is WlnISD available for free? If not can anyone recommend a subwoofer calculator that can work out the frequency response based on volume size?
 

xxGBHxx

Well-known Member
The 28W 4878T01 was recommended to me by Falcon Acoustics if I could stretch to it, however I went for the 4878T00 as it went lower but not as efficient. I'm looking to build a real quality subwoofer that can match expensive subs. I looked at the Seas L26ROY but I'm looking to aim higher. Is WlnISD available for free? If not can anyone recommend a subwoofer calculator that can work out the frequency response based on volume size?
Winisd is free and good for a fairly accurate view. Hornresp is more accurate but a steeper learning curve. Google for both.

Dont be fooled that you need expensive speakers to create an outstanding sub. Almost any of the tried and tested designs and drivers will give you results as good as or better than high end subs and all are usually cheap. High cost doesn't always mean better.

G
 

tazzo1

Active Member
Yea, my previous subwoofer was IPL Acoustics SW5, that sounded really good and was cheap but I was wanting to better it. The Scanspeak has already been ordered and is on its way, I have Scanspeak drivers on my fronts and they sound great, hopefully I have not made a mistake in buying the driver and that the advice I got from Falcon Acoustics was good, time will tell I guess.

Originally my budget was £350 for a driver and the Seas that they recommended was over £120 cheaper, I would assume that they know their stuff?
 

xxGBHxx

Well-known Member
Yea, my previous subwoofer was IPL Acoustics SW5, that sounded really good and was cheap but I was wanting to better it. The Scanspeak has already been ordered and is on its way, I have Scanspeak drivers on my fronts and they sound great, hopefully I have not made a mistake in buying the driver and that the advice I got from Falcon Acoustics was good, time will tell I guess.

Originally my budget was £350 for a driver and the Seas that they recommended was over £120 cheaper, I would assume that they know their stuff?
Who knows!

I tend to be really wary of any retail store recommendations having worked as a scummy Comet store salesman about 25 years ago I'm forever tainted. I know exactly what goes on in retail and the backroom incentives that are given to sell things not on merit but on which offers the best commission. Many of the sales people there would sell their own grandmothers instead of a brick if it gave them another £1 in commission. That is probably grossly unfair to them as I know I personally wasn't like that so (s)he may genuinely be offering you a great buy I just don't know enough to advise.

They also, at best, generally only know about their stock and the product lines they sell that may, or may not be any good. The best line they sell may be the worst line someone else sells for example. Again I don't know anything about Falcon Acoustics so I don't want to say either way.

As for the Scanspeak I'm sure it's a great driver but I'm a terrible consumer in that I'm fanatical about finding and buying the best I can for my money. If I could have got something which is 1% better for the same price or something the same performance for £1 cheaper I will. I spend weeks and even months researching and seeking out the optimum I can get for my money and even I sometimes feel I overdo my analysis and take too long to make the committent. Sometimes 99% is good enough ;)

Also remember that while drivers do of course make a big difference the box size, positioning and room treatments almost certainly make more of a difference.

Incidentally, by "better" what do you mean? Lower? Louder? Faster response? All those are considerations that drive your choices for driver, box size, box type, number of subs, positioning, room treatment etc.

G
 

simonb3665

Active Member
There some test bench reviews online and klippel tests for that driver and I'm sure it will be a great 11 inch subwoofer. Its definately not the most cost effective way to go but if you are limited to a very small enclosure and a small room then you should still have a very nice subwoofer. Its not going to have the output and will start distorting sooner than most of the usual cheaper 15 inch drivers many use but that may not be an issue depending on your use. If its already ordered though then there no point in looking at alternatives. Can I ask why have you gone for the most expensive driver of that size and the cheapest plate amp available?
I am guessing the tune is going to be in the high 20s so you should really have a hpf. Did you design the enclosure or did WA do it for you?
Dayton do some plate amps that have capability of adding eq and a hpf and pretty sure the hypex do as well but have a quick check of the manual.
It would be interesting to hear how you get on.
 

tazzo1

Active Member
Hi and thanks for all the responses, what I am after over my previous sub is better bass clarity and texture. I'm not too concerned if it does not go as low.

The reason I chose the Monacor over others is because it is a pretty good amplifier. I have used it before with an IPL Acoustics subwoofer kit that I bought and it sounded really great. IPL claim that their subwoofers can match commercial ones 2-4 times the cost, and to be honest it was the best subwoofer I have heard. Wilmslow Audio also use the Monacor SAM series in their subwoofer kits.

The reasoning behind the driver was Falcon Acoustics recommended me the Seas L26ROY at £226 as the best subwoofer driver under £350, but to be honest I did not think it would be much better than the driver I got with the IPL Acoustics SW5 kit. They also recommended me the Scanspeak 28W 4878T01 if I could stretch to it. However the subwoofer would not go low enough in a 45L enclosure, so I opted for the 4878T00 which I am hoping is a good step up from the IPL Acoustics driver.

With regards to the amplifier again, I am looking at Hypex Fusion plate amplifiers. but the software looks a bit fiddly with loads of options.

Wilmsow Audio are going to be designing the enclosure, I am thinking of increasing the size of the enclosure to 50L, but with a 3.5 X 3M room, I don't want the enclosure any bigger than that.

Would the hpf be absolutely necessary? Someone on here advised me it would be required if I was going to make the sub ported, but it will be sealed.
 
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simonb3665

Active Member
Hi, sorry I misunerstood. I thought you were going ported. No need for a hpf then.
For box size are you using winisd for the driver and the rms in the box sizes you want or are you just putting it in as big a box as you can accomodate.
The 4878T00 doesnt handle a large amount of power so the sam may be fine but you may find the quality may be limited by the amplifier not the driver when pushed. Probably not an issue it just seemed strange to have a 500 driver powered by a 100 amp (102 on amazon today and has been cheaper). Ive not seen any test of the amp so it may well deliver a clean 300rms in which case it would be a bargain.
 

tazzo1

Active Member
I had WA do the calculations providing them the volume, I'm basically going for a box that would fit in my room. For a 45L enclosure the frequency response at -6db is 31hz. I think a 50L enclosure would suffice. And yes the amp and driver pairing does seem strange but its a great amp for the money .
 
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