Why 12" drivers can't be musical in the 40-80hz? (1 Viewer)

[Jack Gilvey]

WinISD (only program I'm familiar with) doesn't show total system Q. How is this calculated?

It certainly does for a sealed cabinet, which is the only enclosure where is technically applies...I think.
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[Alan Ross]

I have replaced a neat little 12 in. Infinity subwoofer (BU-2) with a dual 18 in. DIY monstrocity. Both are vented. The main speakers were Magnepans, by most accounts "a fast speaker", whatever that means. Well the 18 in. subwoofer integrated a lot better with the Magnepans and produces a much tighter, and obviouly deeper, base. The Infinity was very boomy in comparison.
The speed of a woofer depends on how hard you throw it
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Best regards,
Alan

 

[Alan Ross]

Here is a picture of my closet sub http://gallery.consumerreview.com/au...es/Closet2.asp
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Best regards,
Alan

 

[SteveEdwards]

In WinISD, is the transient response shown in the "Group Delay" graph? I don't see anything about a system Q.

 

[Jack Gilvey]

When you select "closed" for your enclosure, the "Box" tab has a box for volume, under which is the resulting system Q, or Qtc.
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[John E Janowitz]

Daniel writes:
"This is dependent on the used drivers. In general the cone of a 12" driver weights more compared to a 8" driver. So it's possible that the cone move slower."
This is complete BS, and one of those marketing things that is totally wrong. The speed of the bass is the frequency. You take the frequency in cycles per second and can then determine the speed the cone is moving in m/s or in/s, whatever. If the cone moves slower it's playing a lower frequency, plain and simple.
Jones quotes from n0hr:
"The reason we use small woofers (8") is that a large woofer has more mass and therefore is slower than a smaller woofer. A large woofer is slow to start and slow to stop. A smaller woofer will react much faster".
Again, one of the marketing "lies" that many companies use to misinform buyers. If the woofer was slower, then it's not playing the same frequency anymore. It's a shame that many companies now days don't let their products speak for them and have to misinform buyers to make sales.
When you are talking about producing higher frequency bass accurately a few things are important. The size of the cone is not one of them in the 50-80Hz range. For example, the Lambda woofers can all be use up to 500Hz, and some such as the TDX15's can be used up to 2000Hz. These woofers will put most 8" and 6.5" drivers to shame over this range.
As far as the 40-80Hz range goes, a well designed 12" woofer will have much lower distortion than a similarly designed 8" woofer. An 8" woofer with Sd of around 230 sq cm will have to move almost twice as far as a 12" woofer with Sd of around 540 sq cm. This leads to much higher distortion from the smaller woofer at equal output levels.
As Dan said, if both drivers are in the same Q enclosure, say both sealed, Q of .707, the bass should sound the same from both woofers, with the exception of the lower distortion from the larger woofer.
John

 

[Anthony F.]

Jones? You still there?
In answer to one of your questions, here is a 10" sub from Parts Express that seems to have attracted something of a following. I think it's designed for use in a ported cabinet, but I know they sell kits in a sealed design. At the Parts Express site there is a forum where you should be able to get lots of help with this sub. Maybe it's what you're looking for.
Good luck and hang in there....

 

[Jones_Rush]

Anthony,
Thanks for the advice, but I don't think that I will go with a 10"/8" sub after all. I guess that I was just wrong, but you can't blame me with all the marketing BS going around here.
I must say that I really don't think that nOrh is a company which need to promote their products using marketing BS, they sell some of the best 2-way speakers in the world, each 9.0 speaker weigh 80 pounds, due to the fact that they are using marble cabinets for their enclosures, this means that a pair of 9.0 speakers in shipping boxes weigh something like 170 pound , please don't tell me that they are going with 8" sub drivers only because they weigh 10 pound less than 12" drivers, that just doesn't make any sense.
I really think that nOrh believes that a pair of 8" subwoofers will integrate better for music with their speakers. Please don't tell me that nOrh doesn't have a clue of how to design speakers. I own their 9.0 speaker, and took it to my dealer's shop for comparisons, we both preferred the 9.0 over the Nautilus 801, I guess that B&W just doesn't know how to design speakers as well, right ?
Anyway, do you think that adire Shiva 12" driver is one of those drivers which is able to produce 80hz frequencies at the same accuracy of a good 8" driver ?, judging on it's looks, it doesn't seem to be built as good as some other drivers (but looks doesn't count, I guess...)

 

[Jack Gilvey]

Quote:

Unless, of course, the consensus runs contrary to what you want to believe. Then, all bets are off, it seems. Why don't more companies build wonderful 8" subs?
Look,no one will ever be taken to task on this board for sincerely trying to learn, no matter how stupid the question seems. You , on the other hand, choose to make outlandish statements with neither the resources nor the ability to back them up. You are not asking, you choose a stance, then feebly attempt to defend it in the face of those who have infinitely more experience.
Then, as you are wont to do, you leave a thread to start a new ridiculous tangent.
You clearly believe what is posted on the Norh website. Great. Then go with it. Build that 8" sub. If you don't believe that the contrary advice you've received here is worth anything, then why keep posting?
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[Anthony F.]

Jones,
A LOT of people have reported good success with Adire Audio products, especially the Shiva. Dan (who also posted to this thread) seems rather devoted to making a high quality product, and is great with support to this forum and others. If you have an idea of the application you're looking for, I'm sure Adire can help. They recently released the RAVA sub which uses the Shiva in a sealed cabinet with a beefy amplifier for not much more than it would cost you to build (and it looks great). With a sealed design it might be closer to what you're looking for. Good luck.

 

[Jones_Rush]

Jack,
You wrote:
"You clearly believe what is posted on the Norh website. Great. Then go with it. Build that 8" sub. If you don't believe that the contrary advice you've received here is worth anything, then why keep posting?".
In an earlier post, I wrote:
"Thanks for the advice, but I don't think that I will go with a 10"/8" sub after all. I guess that I was just wrong,".
You also wrote:
"That's a good guess, but what marketing BS is taking place in this DIY forum?".
What I meant by "here", is generally on the internet, not specifically at this DIY forum.
You wrote:
"You , on the other hand, choose to make outlandish statements with neither the resources nor the ability to back them up. You are not asking, you choose a stance, then feebly attempt to defend it in the face of those who have infinitely more experience."
First of all, you and I both know that nOrh is NOT the only company saying that. Also, it's a fact that every mid-fi subwoofer with greater than 12" caliber, is usually criticized for not being able to perform well with music, and if you want, I can back it up, both from my own experience and from reviews posted on the net by others.
I have quoted nOrh, only because they have never let me down before. When they said that their 5.5" woofer will reach 27hz -3db in my room, nobody believed it, not at this site, not at any site (not even me), well, it does!.
I belive that nOrh know what they're doing, and when I asked them about their sub, they told me that no, their 8" sub won't perform as good as 12/15" below 30hz, but above, it will reach much better integration with the fronts,
no one believe them here, not even I, does it mean that they are wrong ?.
Since I'm interested in frequencies below 30hz, I will not go with their advice, and it surely helps that experienced people here saying that a good 12" sub will be as good if not better than a good 8" below 80hz.
Regardless to what you might think, Jack, I think that people at this forum have been a great service to me, and I want to thank everyone who replied to my posts including you.

 

[ThomasW]

1)Yes the 5.5" speaker that nOrh uses will produce 27Hz note, so will my headphones and they only have a 2" diaphragm. The issue is 27Hz at what output and how much distortion?
2)The nOrh marble enclosures weight 90lb each. Great! do you understand that this means nothing as far as the QUALITY of the sound is concerned? As long as the resonant frequency of the cabinet is higher or lower than the frequencies being produced by the speaker in the cabinet it doesn't matter what material is used in the construction of the speaker, or how much it weighs. The marble is pretty to look at though.
3)As far as the comparison between the nOrh 9.0 vs the B&W 801 I have serious doubts about the conclusion drawn. For many years I owned a B&W franchise, as a result I'm quite familar with their performance.
The info from nOrh regarding the 9.0 says

-3dB at 29Hz and 22kHz

This makes me wonder how your comparison was done. I seriously doubt that several unbiased listeners in a double blind test would reach the same conclusion.
nOrh speakers have a very loyal cult following, and I'm sure you're pleased with your purchase. But understand that if nOrh had created the holy grail EVERYONE would be beating a path to their door, and as of this point in time I don't see that occuring.

 

[Jack Gilvey]

Quote:

This tone is merely confrontational. Who told you that nOrh doesn't know how to design speakers? The fact is, they choose to present certain facts in a way that is flattering to their product line. This had become too much about nOrh,though...nOrh is irrelevant to me.
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[Jones_Rush]

Jack,
You wrote:
"So now it's greater than 12"? And who's talking about "mid-fi"? You just introduced that to try to make a point about crap commercial subs, but we're talking DIY here, so stick to the discussion on a good one,like the Shiva, in a proper alignment, not a boomy mess."
I have used the commercial subs argument just to make the point that when all things being equel (even if equel = bad quality), you can clearly see the difference between larger cone subs to smaller. There is a lot of positive reviews about 10/8" commercial subs saying how well they integrate with music. The Shiva is in another category, right, but since we talk DIY, the DYI 8"/10" drivers are also in the same categoty as the Shiva, and when all things being equel...
Anyway, since experienced people here have given some very strong arguments about why a good 12" sub can easily beat a 8" sub, and since I don't have the experience to claim otherwise, I thought it will be interesting to see what will nOrh have to say about it, here is their reply:
"Not long ago, the goal was to find a woofer with the lowest possible moving mass for a subwoofer. This is because a woofer with lower mass is easier to control. It has less overshooting and is easier to stop.
Some of the best subwoofers ever are based around 8 inch designs. The Shahinian Double Eagle Subwoofer and the Steward Hegeman Contra Bombarda (spelling) are two such subwoofers.
Generally speaking, to get good bass from a ported design, an 8 inch woofer will need about 50 liters, a 10 inch will need over 100 and a 12 inch will need over 200 liters.
The problem that a larger woofer has is that it has more mass and it also has more resistance as it pushes air. It is not that different that trying to have a race between a sports car and a dump truck. No matter how much power you give the dump truck, the sports car will genearlly perform better.
Recently, a new generation of subwoofers have appeared. The goal was to create subwoofers in small cabinets. This would be less expensive for the manufacturers to build and it would be cheaper to ship. To do this, the manufacturers increased the moving mass. Most of this mass was added
to the voice coil so that they could extend the excursion of the woofer.
Even so, the natural rolloff for these woofers would be about 40 to 50 hz in a 20 liter cabinet. To extend the bass further, equalization is applied.
I believe that allowing a woofer to operate in its normal limits without equalization will have less distortion. I believe that an 8 inch woofer will work better than a larger woofer for music. An exception to this might be the Scanspeak 25W-8565. This woofer has a very low moving mass
for a 10 inch woofer and will produce -3 dB at 23 Hz in a 161 liter cabinet.".

 

[Jack Gilvey]

Goody, more from nOrh.

It is not that different that trying to have a race between a sports car and a dump truck. No matter how much power you give the dump truck, the sports car will genearlly perform better.

That's a pretty bad analogy,also. If you design a transient-perfect, 0.5 Q sub, around a 12" driver, that means that the motor is sufficient to allow the cone to start and stop when the signal does. That's what transient perfect means. That type of thing is put in there to impress beginners such as yourself, being pretty easy to understand. That is a commercial site designed to sell speakers to folks who have little or no knowledge of the actual workings of a loudspeaker. It relies on people's experience with the same bad commercial subs that form the sole basis of your experience.
If you choose to respond, please do do with actual independent sources, not commercial sites.
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[Chris_Campbell]

I'm not really all that eager to participate in a flame war here, but come on guys, let's take it easy here. No need for the inflammatory comments.
Jones, I think you'll typically find on this forum that most people will defend 12 and 15" subs to the last, because most of the DIYers here have built one. You know how people are about products that they own. But in this case, I have to agree with them, as the owner of a recently built DIY sonosub (using not a 12, but a tempest 15). And let me tell you, this thing is tighter than my old velodyne sealed 12 (with PR). I really think you'd be amazed if you heard a properly built (not to imply my hack job is) sub using a larger driver. I mean can so many people here (some of which pretty much devote their lives to the accurate reproduction of bass, such as TV and TN) really be lying to you? While I agree that a well built 8" is definitely going to be tighter than a comparable 12 or 15", there are the tradeoffs. For home theater and music, I would gladly trade a bit of musical precision for much lower extension. I believe it's your call. Good luck
To everyone: I meant no disrespect in any part of this post, and I know most of the individuals here have much more experience than me in this field, I'm just offering my 2 cents.

 

[Deane Johnson]

Chris:
Actually, I don't think you will find that this is a flame war. It's simply that Jones has made some provocative statements in several threads, including one on the BFD, that are not based on fact. To let these go unanswered misleads other forum members into thinking they are true. Then they get repeated or fixed in someones mind, and away they go.
Given the misleading comments Jones has made in several instances, though I suspect innocently, this has
remained pretty civil and informative.
And I do have to say in his defense, he takes his beatings well and I hope something benefical is coming out of it for him.
Deane

 

[Jeff Rosz]

jones,
do you know of anyone who has built a 12 or 15 inch sub along the lines of the shiva/tempest/mass/sonosub? seek out such a person and bring your fav cd with you and give it a listen. its like that first time yer paw gave ya the keys to the buick and a $20 bill. anyway, the sound is truely room filling and you will get a nice warm feeling. and the first thing you will say is "HOLY ****!". it WAS the first thing i said and i wouldnt have been ashamed at offending my mother if she would have been there. i think you will be surprised at the "accuracy" such a sub will produce. the folks on this forum are not lying to you. and if someone was lying, it would be caught right there on the spot too. like i said, give it a listen. thats the true test.
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*why build one when you can build two for twice the price*
jeff

 

[Jack Gilvey]

I meant no disrespect in any part of this post

None taken at all. Just interested in facts.
I second Deane's comments. Well said. Anyone reading the whole thread will come away with the same impression.
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[TysonN]

Hmm, thought I would throw in my .02 here for what it is worth. I own both the SVS 20-39 sub and the nOrh subs. Just a few observations on both subs (BTW, I am extremely happy with both subs & I am not going to dis either one, just trying to stick to facts here). That said, the norh subs are definitely tighter sounding & "faster" on transients than the SVS, but not by a whole lot. The SVS sounds better with music than any commonly available commercial sub in its price range that I have heard, all of which tend to sound loose and boomy to me. For 2 channel music at up to around 103db, I prefer the nOrh subs. But for HT and music that is very loud (around 110db), I prefer the ultra deep bass and output capabilities of the SVS (and it stays linear even at very loud levels, which is very nice). The nOrhs are definitely limited in overall output, especially down low. They are flat to 24hz in my room at moderately loud levels, but once you hit higher SPL's the below 30hz stuff drops off quite a bit & then they bottom out soon after that. But I very rarely ever listen that loud. For most music at moderate to moderately loud levels, the nOrhs still have a very full but very precise sound with excellent tonal variation in the bass notes & excellent transients. This is not suprising since they tune the sub for a low Q (around .5 I believe), use Vifa's top of the line 8 inch woofer, and have an absolutely monster power amp behind them (one of the nOrh transformers is bigger than BOTH of the transformers in my Bryston amps). That is the strength of the nOrhs. But, on the flip side, the nOrhs don't really cut it in HT apps or other high output/SPL apps. Just not enough output overall & not enough output down low. For that you are much better off with a sub like the SVS, which can shake the walls, kick you in the chest, and STAY LINEAR. Since I have 2 systems, one for music & one for HT, I just got the sub I felt was optimized for each application. If I could only afford 1 system, I would probably go with the SVS as it is able to do a good job with music & a great job with HT, while the nOrh is great at music but does not do a very good job with HT (I don't think it was really designed for HT apps, though). In fact, I will go further & say that IMHO, the norh subs were not designed to be "subs" at all, but were specifically designed to compliment the 2 way bookshelf speakers that nOrh makes & turn them in to full range tower speakers. If looked at that way, then there really is no debate as to which is "better", they simply perform different functions.