Sure, but you bought a driver that had a posted graph, yes? Goes to prove my earlier point that drivers with "real" frequency response graphs tend to be of better quality.
I would include SEAS, Vifa, etc. on this category. I specifically do not include the house drivers sold directly and exclusively through some of the retailers.
I repeat: Do not buy any driver based on a T-S simulation plot. Insist on a real frequency response graph of a real driver in real space. There's a reason they don't post real graphs, and it's not because the dog ate their homework.
Grey
I would include SEAS, Vifa, etc. on this category. I specifically do not include the house drivers sold directly and exclusively through some of the retailers.
I repeat: Do not buy any driver based on a T-S simulation plot. Insist on a real frequency response graph of a real driver in real space. There's a reason they don't post real graphs, and it's not because the dog ate their homework.
Grey
I also don't want to turn this into one of those threads as you say.... don't get me wrong I do agree with most of you points, it is *very* prudent to cast a over sceptical eye over T&S paras and sims.
I do disagree that whan you say there are no speakers flat to 20hz in room without EQ.
The have been multiple anechonic tests of subwoofers that play flat to 20hz as long as they stay within power compression limits.
Take two 20hz tuned vented designs once of Bkelec in the UK and one form Svsubwoofera in the US.
http://www.avtalk.co.uk/forum/index.php?t=getfile&id=5987
Monolith DF.
A few db down at 20hz but with a few db room gain it can be flat.
http://www.avtalk.co.uk/forum/index.php?t=getfile&id=4710
SVS Same again very minor db roll off.
As long as the room is not too big and you smooth any room bumps out, flat is not impossible without EQ.
I totally agree with GRollins real life testing is very important a firm hold of reality is wise.
I do disagree that whan you say there are no speakers flat to 20hz in room without EQ.
The have been multiple anechonic tests of subwoofers that play flat to 20hz as long as they stay within power compression limits.
Take two 20hz tuned vented designs once of Bkelec in the UK and one form Svsubwoofera in the US.
http://www.avtalk.co.uk/forum/index.php?t=getfile&id=5987
Monolith DF.
A few db down at 20hz but with a few db room gain it can be flat.
http://www.avtalk.co.uk/forum/index.php?t=getfile&id=4710
SVS Same again very minor db roll off.
As long as the room is not too big and you smooth any room bumps out, flat is not impossible without EQ.
I totally agree with GRollins real life testing is very important a firm hold of reality is wise.
tinitus,
Phase is a nuisance, make no mistake. Especially considering the wavelengths involved. It's no wonder that subwoofers are usually set back from the main speakers. To get real control over phase, you have to go digital or use first order crossovers, but that opens yet another can of worms. It's a thorny issue.
micb,
"Multiple anechoic tests" of what drivers in what cabinets and how many PI of radiating space?
A little more homework is in order.
Your first link appears to me to be 6dB down ref. 50Hz. That's not my ideal sub, although it would certainly please a lot of people. Note that http://www.bkelec.com/HiFi/Sub_Woofers/monolith.htm clearly shows a plate amp. You're assuming there's no frequency tailoring going on. I imagine you'll find that there's quite a bit. Read the website carefully or e-mail them.
Furthermore, assuming that you're referring to the powered subs at http://www.svsubwoofers.com/subwoofers.htm they specifically mention EQ.
I repeat: 20Hz without EQ is a non-starter. The best you can hope for is about 30-35Hz; more commonly 40-50Hz, flat. It's amazing how many people think that's "real" bass. When I say I want 20Hz, I want it no worse than -3dB, but preferably -1dB. And certainly none of this "useable bass" nonsense, which seems to be bafflegab for -10dB.
Show me real drivers in real cabinets that achieve 20Hz without EQ and I'll buy them...and thank you for it.
Grey
Phase is a nuisance, make no mistake. Especially considering the wavelengths involved. It's no wonder that subwoofers are usually set back from the main speakers. To get real control over phase, you have to go digital or use first order crossovers, but that opens yet another can of worms. It's a thorny issue.
micb,
"Multiple anechoic tests" of what drivers in what cabinets and how many PI of radiating space?
A little more homework is in order.
Your first link appears to me to be 6dB down ref. 50Hz. That's not my ideal sub, although it would certainly please a lot of people. Note that http://www.bkelec.com/HiFi/Sub_Woofers/monolith.htm clearly shows a plate amp. You're assuming there's no frequency tailoring going on. I imagine you'll find that there's quite a bit. Read the website carefully or e-mail them.
Furthermore, assuming that you're referring to the powered subs at http://www.svsubwoofers.com/subwoofers.htm they specifically mention EQ.
I repeat: 20Hz without EQ is a non-starter. The best you can hope for is about 30-35Hz; more commonly 40-50Hz, flat. It's amazing how many people think that's "real" bass. When I say I want 20Hz, I want it no worse than -3dB, but preferably -1dB. And certainly none of this "useable bass" nonsense, which seems to be bafflegab for -10dB.
Show me real drivers in real cabinets that achieve 20Hz without EQ and I'll buy them...and thank you for it.
Grey
I have done my home work. Your amp querys were incorrect.
http://www.bkelec.com/Modules/bsbpv500.htm
As you can see on bypass mode the amp is it is flat down to single digits -3db @ 3hz.
SVS plate amps use PEQ only for cutting freqs only, so no EQ "boost" envloved.
And as for the freq response while that may be 6db down anechonic measured as I said before in room you should get least 6db gain so you are looking at a flat response.
I think we should lay this to bed now because there is little point going on as we don't not want to totally kill this thread.
So my final word for now "Too much bass" no such thing
http://www.bkelec.com/Modules/bsbpv500.htm
As you can see on bypass mode the amp is it is flat down to single digits -3db @ 3hz.
SVS plate amps use PEQ only for cutting freqs only, so no EQ "boost" envloved.
And as for the freq response while that may be 6db down anechonic measured as I said before in room you should get least 6db gain so you are looking at a flat response.
I think we should lay this to bed now because there is little point going on as we don't not want to totally kill this thread.
So my final word for now "Too much bass" no such thing
I've still got my old tempest cabs in the garage. I'm having a really bad week right now - my cars gearbox blew on Friday, and I just bought a replacement which overheated on the way home.... Still have no car to go to work and back and £2000 down.... Anyway I digress.. Over the next couple of weeks I'll try and measure a tempest outside to see how it looks against the model.
btw my tempests were ~Q 0.61, so they should be around -10dB / 20Hz outside anyhow. We need room gain to be happy
Cheers,
Rob.
btw my tempests were ~Q 0.61, so they should be around -10dB / 20Hz outside anyhow. We need room gain to be happy
Cheers,
Rob.
micb,
It says "+6dB Eq selectable at 15,20,25 and 30Hz" right up at the top of the page in the "Features" section. In other words, they're using a moderately high Q--about 2, let's say--high pass filter with selectable frequencies. The boost before rolloff (see filter response graph at the bottom of the page) compensates for the falling frequency response of the driver. Child's play. People have been doing this for years. One benefit of this approach--as opposed to, say, the Linkwitz circuit, or the method I chose--is that there's a subsonic filter built-in. The downside is that it's not quite as versatile. As with anything, there are tradeoffs.
Of course the amp is flat in bypass mode. I should darned well hope so. The question is what happens to the sub response as a whole when the EQ is cut out. No longer such a rosy picture.
Rob,
I'll be interested to see what you come up with. Here's hoping that your life straightens out.
Grey
It says "+6dB Eq selectable at 15,20,25 and 30Hz" right up at the top of the page in the "Features" section. In other words, they're using a moderately high Q--about 2, let's say--high pass filter with selectable frequencies. The boost before rolloff (see filter response graph at the bottom of the page) compensates for the falling frequency response of the driver. Child's play. People have been doing this for years. One benefit of this approach--as opposed to, say, the Linkwitz circuit, or the method I chose--is that there's a subsonic filter built-in. The downside is that it's not quite as versatile. As with anything, there are tradeoffs.
Of course the amp is flat in bypass mode. I should darned well hope so. The question is what happens to the sub response as a whole when the EQ is cut out. No longer such a rosy picture.
Rob,
I'll be interested to see what you come up with. Here's hoping that your life straightens out.
Grey
GRollins
Sorry to ask, but do you mind to take a look at these graphs and thell me if you think i can build usable HT subs with these?
I have already 2 of the 12`s and 2 of the 15`s
http://www.rockfordfosgate.com/rftech/library/1998/5_Subwoofers/RFR2212-TS.pdf
http://www.rockfordfosgate.com/rftech/library/1998/5_Subwoofers/RFR2215-TS.pdf
I do currently run the 12`s in the recommended sealed volume and dont really think the sound is so bad, but i am very curious about how the 15`s vould do in a pair larger ported boxes, like 160L ported to 23 hz . (atleast in Caad 4,0 from Monacor this looks like good Subwoofer, but what could i espect in a rather large livingroom?)
Since my only eq is an regular Technics 7 band graphic eq, i have really no equipment suitable for equing subs in my possesion
Sorry to ask, but do you mind to take a look at these graphs and thell me if you think i can build usable HT subs with these?
I have already 2 of the 12`s and 2 of the 15`s
http://www.rockfordfosgate.com/rftech/library/1998/5_Subwoofers/RFR2212-TS.pdf
http://www.rockfordfosgate.com/rftech/library/1998/5_Subwoofers/RFR2215-TS.pdf
I do currently run the 12`s in the recommended sealed volume and dont really think the sound is so bad, but i am very curious about how the 15`s vould do in a pair larger ported boxes, like 160L ported to 23 hz . (atleast in Caad 4,0 from Monacor this looks like good Subwoofer, but what could i espect in a rather large livingroom?)
Since my only eq is an regular Technics 7 band graphic eq, i have really no equipment suitable for equing subs in my possesion
Looks to me as though they're cut from the same cloth as the drivers I mentioned earlier. All my earlier comments still apply--in particular:
--Don't buy them unless you intend to apply EQ to get them flat.
It's your money, do as you wish, but don't say that you weren't warned. Personally, I wouldn't touch 'em with a ten foot pole. This class of drivers needs too confounded much fiddle-factor for the average critter to pound them into shape.
Grey
--Don't buy them unless you intend to apply EQ to get them flat.
It's your money, do as you wish, but don't say that you weren't warned. Personally, I wouldn't touch 'em with a ten foot pole. This class of drivers needs too confounded much fiddle-factor for the average critter to pound them into shape.
Grey
The 12 and the 15 seem to have quite similar specs (eg: fs, Qts). If you (for arguments sake) put the 15s into a closed box 2.5-3 times bigger than the 12s, the sound should be quite similar. The 15s do appear that they'll play a little louder below 100Hz without making any other changes to your system.FE3T said:
Doing a little Googling i ran across this
http://www.audioholics.com/productreviews/avhardware/OnixRocketDigitalEqualizationSystemp1.php
another maybe easyer to understand review with a few great tips
http://www.hometheaterhifi.com/volume_13_3/onix-r-des-subwoofer-eq-9-2006-part-1.html
Any qualified ideas about how this would help flatten things out.
The rewiew seems to indicate that there are gains to find
http://www.audioholics.com/productreviews/avhardware/OnixRocketDigitalEqualizationSystemp1.php
another maybe easyer to understand review with a few great tips
http://www.hometheaterhifi.com/volume_13_3/onix-r-des-subwoofer-eq-9-2006-part-1.html
Any qualified ideas about how this would help flatten things out.
The rewiew seems to indicate that there are gains to find
GRollins said:
Greets!
'Cheating' is a strong accusation, so decided to pursue it:
http://www.hostboard.com/cgi-bin/ultimatebb.cgi/ubb/get_topic/f/3729/t/2316#11
Frankly, since he makes no claims about how it occurred beyond high SPL, I don't see how it can be cheating even if true, so unless you have some proof that something other than high SPL did it, then a retraction/apology is in order.
GM
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