So I changed the specs. best I could to match Bjornos calculated specs, and the response curve didn't change. The excursion DID change and sensitivity vs power went way up. You know winISD tried to warn me I just didn't know any better. So people are giving fake specs now? Thats allowed? the lack of xmax would be disappointing when expect much more. =(
IH8 - if a woofer moves more air it would require less travel to create the same spl of bass which in turn would make it more accurate, thats why using a large woofer for bass is a good thing.
IH8 - if a woofer moves more air it would require less travel to create the same spl of bass which in turn would make it more accurate, thats why using a large woofer for bass is a good thing.
If a big wheel covers more ground per rotation they why aren't cars fitted with 40" wheels?
Because they would be less agile, less responsive, require more energy to get moving and more energy to stop.
Bigger is not always better.
The size of the tire should also be complimented by the motor. A huge motor doesn't move very fast with skate board wheels either. What about a medium motor with helicopter blades, or a horse running in grass with horse shoes.
Seriously, I'd think it'd be a matter of power/work, and maintain a standard of how much power is being applied to the amount of work to be done. A smaller speaker with a lower motor power to speaker size ratio isn't more responsive.
Seriously, I'd think it'd be a matter of power/work, and maintain a standard of how much power is being applied to the amount of work to be done. A smaller speaker with a lower motor power to speaker size ratio isn't more responsive.
Correct! There's been a surprising number of folks on the various forums over the years that don't understand this mass Vs motor strength 'thing', so after one particularly 'lively' thread on the subject a technical paper was done for us to refer to: http://stereointegrity.com/wp-content/uploads/WooferSpeed.pdf
GM
GM
Dayton has a pretty good 'track record', so wouldn't worry about them, but mobile audio is a highly competitive market of folks with different [total] performance requirements, i.e. price, size, ease of installation, performance and usually in that order, so like occurred in the '60s era 'muscle car' horsepower 'wars' there's a lot of questionable marketing in mobile audio.
What's worse though is it too often occurs in high end/boutique audio. In short, I've always limited any serious sound system design to prosound components that prove themselves to be worthy of the cost/effort.
GM
You bet, that's correct. What I mean is that in my setup with 2 of them sealed provides no "practical" limitations because it provides adequate output. I don't need more. Essentially my point is that I would simply use more sealed woofers than you might need vented. Thanks for clarifying that.
I mean, when I put in the "corrected" thiele parameters the performance went up sooooooo. Xmax was the only thing that went down. Cerwin Vegas aren't exactly out of the picture yet. The xmax hypothesis wasn't exactly dead science either, but based off a 2d picture. But I digress, I'm finding bass arrays pretty interesting.
Last edited:
Theres two aspects that seem to stand out. group delay, which is how long it takes for the speaker begin producing a signal. WinISD can show us this. The other is how long it takes for the speaker to stop moving when signal has stopped, which is spectral decay. Spectral decay would be affected by the damping characteristics of the speaker and also the amp.
I think thats how it goes.
You can't blindly say that a sealed speaker has a lower group delay than ported, you better run the sim, like for me, trying to stick with a fixed box might not be optimal for a speaker though acceptable, and the ported optimal box had better group delay. I think it is safe to say that acoustic suspension does however win, in the terms of spectral decay.
Bjorno - When I look at the Dayton Ultimax 15"s surround...it makes it a lot more obvious that you are most likely right!
Last edited:
I know many disagree with me, but the longer I'm in this hobby, the more skeptical I am of attributing too much of subjective quality to measured or simulated quantities. Like amplifiers, we have found some stuff to measure, we focus on that, not realizing that it only explains a part of the subjective quality. Now, it's a big part, don't get me wrong, but saying that the bass quality a driver is capable of can be predicted very accurately by certain measurements /sims might be a stretch. My experience is that a huge magnet and an aluminum cone seem to be a help, but I'm not sure that will be reflected well in any Sim.
Whats not a stretch is that your ears will lie to you. If you had of read the article GM posted you would known, that a large magnet, as well, as a more powerful magnet type, directly attributes to better transient response.
You need to understand the concept that something can sound more accurate but not actually be. Accurate, to our ears, is a subjective term. Accuracy, measured by numbers, is not, because our measuring equipment has no feelings nor any preconceived notions of what accuracy should sound like.
Here is an example of how to get "tighter" bass which has nothing to do with accuracy to the signal but everything to do with our perception of what accuracy is. Take a high pass filter and place it at say 40hz....way tighter now, not accurate to the signal. You just eliminated some of the signal load, ie bandwidth, but still have access to the same out of power. The driver doesn't have to make as large excursions, thus it can focus even more energy on its new pass band. Still, its not accurate.
You need to understand the concept that something can sound more accurate but not actually be. Accurate, to our ears, is a subjective term. Accuracy, measured by numbers, is not, because our measuring equipment has no feelings nor any preconceived notions of what accuracy should sound like.
Here is an example of how to get "tighter" bass which has nothing to do with accuracy to the signal but everything to do with our perception of what accuracy is. Take a high pass filter and place it at say 40hz....way tighter now, not accurate to the signal. You just eliminated some of the signal load, ie bandwidth, but still have access to the same out of power. The driver doesn't have to make as large excursions, thus it can focus even more energy on its new pass band. Still, its not accurate.
Something has never made sense to me regarding the article gm posted. If you apply a line level digital xo filter to the signal going to the driver under test and obtain an impulse response, the result will show slower rise time just as it would if an inductor was used in series with the driver. In other words, doesn't the change in impulse response simply mean that some higher frequencies were filtered from the signal? Since every woofer has xo filtering supplied anyway in use, what relevance is the impulse response of the bare driver? I know it sounds like it should be a good indicator of driver "speed" but I'm not sure it means much since the impulse response of any woofer with crossover applied will look "slow". Perhaps I am missing something.
I think redordar (correct any rude error please):
It is not the L (inductance) but the impedance that the manufacturers measure at different frequencies.
There are no defined standards, but it is considered that the twoofers are measured at 100 hertz, the average ranges and / or extended range at 1000 hertz and the tweeters at 10000 hertz.
And the VC (voice coils) are not only inductances that vary the final impedance according to the working frequencies, they also involve the capacitance (C) (between the coil and the pole piece) and the resistance (R) typical of the wire (number of turns), all simultaneously as the coil moves within the magnetic field of the speaker.
In electronics, the three combined values form a reactance, and according to the pre-eminence of the other two values, it will be a capacitive (XC) or inductive (XL) reactance
I imagine that in the calculations of the final impedance of a speaker they should be considered, but ... they will do it? Maybe they are insignificant influences .....
It is not the L (inductance) but the impedance that the manufacturers measure at different frequencies.
There are no defined standards, but it is considered that the twoofers are measured at 100 hertz, the average ranges and / or extended range at 1000 hertz and the tweeters at 10000 hertz.
And the VC (voice coils) are not only inductances that vary the final impedance according to the working frequencies, they also involve the capacitance (C) (between the coil and the pole piece) and the resistance (R) typical of the wire (number of turns), all simultaneously as the coil moves within the magnetic field of the speaker.
In electronics, the three combined values form a reactance, and according to the pre-eminence of the other two values, it will be a capacitive (XC) or inductive (XL) reactance
I imagine that in the calculations of the final impedance of a speaker they should be considered, but ... they will do it? Maybe they are insignificant influences .....
<- This, thats why I posed the information above, there seems to be a connection to impedance. Also, people think that lower impedance is more efficient when in actuality its not, its less.
First we must be clear that efficiency is not the same as sensitivity, the latter measured in decibels (dB) and called SPL (sound pressure level)
And yes, the lower the impedance (speaking of solid state circuits) the power delivered by the amplifier rises, but the distortion increases.
You can see it clearly in the specifications of an amplifier.
Agree for the most part, though we can within the range of the box sim, which is limited to the bandwidth between the driver's upper and lower effective mass corners:
Flc = Fs*Qts'/2
Fhm = 2*Fs/Qts'
Qts' = Qts + any added series resistance [Rs]: HiFi Loudspeaker Design
GM
An amp ran at higher ohms is more efficient, though you may increase output as a whole, by running at lower ohms, to a higher percentage, you lose signal to THD and heat. Apparently we also add transient response degradation to that net less.
Last edited:
Did I say this backwards? For some reason that I can't remember I lead myself to believe that a higher impedance would result in lower inductance, but from some post I came across on this board, it seems that with a DVC woofer wired in parallel, the inductance decreases
DVC Woofer- Does series vs parallel alter T/S parameters?
DVC Woofer- Does series vs parallel alter T/S parameters?
The thread tells it like it is, so you're correct in that the higher the impedance the more it's voltage controlled/sensitive and lower is current controlled/efficient, ergo increase's thermal power distortion. etc..
Motor design will determine VC inductance, then series wiring of multiples increases it and in parallel lowers it.
GM
Motor design will determine VC inductance, then series wiring of multiples increases it and in parallel lowers it.
GM
- Status
- Not open for further replies.