I thought the smirk remark was for me actually... 😉
Regarding high Q's, I remember reading that market research done by some hi-fi manufacturers in the 70's or 80's showed most consumers preferred a Qtc of about 1 with an F3 of about 60Hz and that most musicians even thought the lowest tone on a typically-tuned electric bass guitar (41Hz) sounded best on such a speaker 😛
Regarding high Q's, I remember reading that market research done by some hi-fi manufacturers in the 70's or 80's showed most consumers preferred a Qtc of about 1 with an F3 of about 60Hz and that most musicians even thought the lowest tone on a typically-tuned electric bass guitar (41Hz) sounded best on such a speaker 😛
A 1980-model 18" Pyle driver in a 6.5 cubic foot sealed box. F3=high 50's, Qtc about 1. Best bass guitar speaker I ever heard. The bottom end just sounded right, and nothing Eminence made at the time sounded as nice in the upper mids.
Also had better bottom end (playing stuff like Planet Rock) than the W-bins that the big boys were all using.
Hehe... so like this for the OP:
LTW to tame the bump: F0 65Hz, Q0 1.9, Fp 65 Hz Qp 1.0 (zero gain)
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
LTW to tame the bump: F0 65Hz, Q0 1.9, Fp 65 Hz Qp 1.0 (zero gain)
The quality of mature audio judgment seems be increasing. The math of design such as InOtIn displays (which I never argue with, assuming for the moment it is all OK) are good to see. But the question, as understood by wg_ski is what is the listener experience we can infer from the sim information.
For sure, the curve with the modest 5 dB thump (assuming that is what would be heard at the listener's seat) would sound much better than the flat curve (typically advocated by the sim advocates) which would sound very bass-poor. Anybody doubt that?
But the low end is not as low as people would like today, except for unsophiscated pop, electric guitar, and dance music people who often love a thump at 50 - 60 Hz most of us would consider atrocious*. So, better would be a larger box with a lower frequency thump.
Ben
*and related in many minds to the upper resonance of ported boxes
For sure, the curve with the modest 5 dB thump (assuming that is what would be heard at the listener's seat) would sound much better than the flat curve (typically advocated by the sim advocates) which would sound very bass-poor. Anybody doubt that?
But the low end is not as low as people would like today, except for unsophiscated pop, electric guitar, and dance music people who often love a thump at 50 - 60 Hz most of us would consider atrocious*. So, better would be a larger box with a lower frequency thump.
Ben
*and related in many minds to the upper resonance of ported boxes
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AAMOF, the curve with the 'modest' thump represent a Qtc of 1.94 and the 'flat' curve is still a relatively high Qtc of 1.0.
Hi,
I do for one. I actually advocate sim alignments with less bass than flat.
The reason ? Room gain and deep bass extension. The 5dB "thump"
means one note low bass, and cutting back the bass control to
control it with the room gain = no low real bass extension.
Maximally flat bass responses can still sound one note in rooms,
especially if the cut off coincides with a major room mode.
Best speaker alignment depends on the intended placement.
Full freespace placement can utilise room gain for tight deep bass,
as long as the speaker has a slow well damped tight bass roll-off.
rgds, sreten.
FWIW the GRS driver is typical of old schoool "impressive" bass.
I doubt that, too. "Modest 5 dB" thump (Qtc=1.9) is the worst sound quality you can get from a sealed box. OK, you can get even worse sound quality with 6 dB thump. Much better sound quality come with Qtc=0.8 or less. And the best is with Qtc below 0.6.
At the listener's seat all of that is very easy to hear and measure. "No stinking sims" here! But the sims tells exactly the same. And the theory. Please, please take a look at the Figure 6 (Normalized step response of the closed-box loudspeaker system) from "Closed-box Loudspeaker Systems Part I - Analysis" by Richard Small.
Yes, I doubt that too, that bass bump will sound boomy in a typical domestic room UNLESS there's a room induced null at the same frequency AND a room mode boost lower in frequency to bring up the low end. A bump like this can be pleasing for a short while(especially if there's no low bass in the music, like 80's rock) but it quickly becomes distracting and then irritating with fuller spectrum music, it's annoying when all the low notes are missing. If there's going to be a bass bump built in I'd much rather have it at 25 hz or lower and OP's driver won't do that no matter how big the box is. With 32 hz fs you can't push the bump down anywhere near low enough for my personal taste.
I've told you many times, the boom from ported boxes that you don't like is not a resonance problem, it's the popular "max flat" response curve boosted in the low frequencies by room gain. If you design a ported box with a rising response similar to typical low q sealed boxes it will sound like a sealed box. You don't hate ported boxes because they use resonance, you hate them because you've never heard one that was designed to compliment the room gain curve properly so it didn't sound too boomy.
5 dB bump at 50 Hz (at the listener's seat, as I've been saying) is undetectable for this speaker except as an attractive but subtle enhancement over flat, esp since a modest sized room will have peaks and dips of 20 dB.
Ben
Ben
Why would you assume the 5 db bump at 50 hz would measure as a 5 db bump at the listener's seat if you know the room can chop the response up?
Since you haven't measured OP's room gain curve at the listening position it is naive and irresponsible to advise that he should have a 5 db peak built into the design and furthermore to claim that it is going to be undetectable and then later claim it would be an enhancement over flat response.
What if the 5 db box peak coincides with the same frequency as a 20 db room mode? What if there's a further 2 or 3 db of room gain at that frequency (which is possible if the room is small and fairly well sealed)? Then it's a 28 db peak at the listening position, not a 5 db peak. And it might have a 20 db room induced null on either side of it which would make it the literal definition of one note bass.
The fact is that we seldom (almost never) have any idea of what's going on in anyone's listening room, so often the best we can do is design for a flat response in a typical domestic room, which means a slightly rising response (like .5 or .6 qtc), NOT a 5 db peak. We have to disregard the room's peaks and nulls when we give advice since we have no way to predict them. Your naive opinion that the 5 db peak would be an enhancement may be correct or incorrect depending on the room, the listening position in the room, and the subjective user preference, none of which any of us know anything about. Most educated designers will prefer to err on the side of neutrality when giving advice in light of all this.
1. You can still pick out a boomy speaker, even with 20dB peaks and dips caused by the room. Every sound, from every source, that is made in the room is affected by it and your ear eventually tunes it out. A bass fiddle played in the room will still have 20dB peaks and dips - but will sound perfectly natural.
2. If this one were +5dB at 50 it might (will) sound pleasing with rock/pop. But it's at 70 Hz, which will sound like poo - like everybody else's cheap speakers. Make the box bigger until you DO get it down to 50-ish. Lower is better still but there are practical limits.
2a. You could probably force this speaker to be flat to 20 if you built an insanely long terminated quarter wave pipe enclosure, and stuffed it to the point of being down to 64dB/1M/1W. This goes back to "practical limits".
3. Next time get a lower Q woofer. Practice your crossover design on this one before you go and spend a great deal of money on the next. Better speakers aren't as forgiving of rookie mistakes.
Let's not forget that high-Q is symptomatic of cheap drivers that usually have other limitations as well.
In this case, I believe that driver has an Xmax of just 3.5mm. Even good 6.5" drivers have better excursion capabilities than that.
In this case, I believe that driver has an Xmax of just 3.5mm. Even good 6.5" drivers have better excursion capabilities than that.
Hi,
Its a cheap 12" driver designed as a replacement for cheap 12" bass
units in cheap 12" multiway speakers that are generally very poor.
rgds, sreten.
Its a cheap 12" driver designed as a replacement for cheap 12" bass
units in cheap 12" multiway speakers that are generally very poor.
rgds, sreten.
High Q id symptomatic of high Q and that's all. There are very high quality drivers made for OB.
There are also very high quality drivers with very low xmax made for horn loading.
It's symptomatic in the same way that high body temperature is symptomatic of having a fever. Yes, you can have high body temperature if you're just run a few laps on the track, but that doesn't invalidate the statement.
It's not a controversial observation that cheap drivers, especially cheaply produced subwoofer drivers lacking in significant motor, tend towards having very high Q.
It's not a controversial observation that cheap drivers, especially cheaply produced subwoofer drivers lacking in significant motor, tend towards having very high Q.
Hi,
Generally yes, but it depends on the driver and compromises.
Its not good if it requires a huge box over say Qbox = 0.7.
rgds, sreten.
With regard to the original question have you tried UNIBOX, its free and a spreadsheet with a fulsome driver data base thats east to add too. I found it very easy to use and simple to compare different drivers, box sizes etc. With regard to boominess it also plots transient response as well as Xmax for a given Pin. Hope this helps 🙂
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