we have pretty much the same driver mike, i wouldn't say its bullet proof, the cone is only made of paper, but doesn't matter i cannot see that side
car audio woofers do seem abit more solid, because boy racers need them to be when there feeding them "1000w" from a "1000" amp which is clipped to ****, plus chavs like to kick things so there subs double up as punch bags, but in real life non chav use, a paper cone is fine so long as its ridged,
though with the eminence i was surprised that u have a massive die cast frame and huge vented magnet, and then just a thin paper cone with cloth surround, but then again i guess it needs it for efficiency
however less efficient car audio woofers seem to be more efficient at lower frequency's if u look at the response graphs so they may be better
car audio woofers do seem abit more solid, because boy racers need them to be when there feeding them "1000w" from a "1000" amp which is clipped to ****, plus chavs like to kick things so there subs double up as punch bags, but in real life non chav use, a paper cone is fine so long as its ridged,
though with the eminence i was surprised that u have a massive die cast frame and huge vented magnet, and then just a thin paper cone with cloth surround, but then again i guess it needs it for efficiency
however less efficient car audio woofers seem to be more efficient at lower frequency's if u look at the response graphs so they may be better
MaVo said:
MaVo and Naudio, let me try to educate you guys on a few things. I don’t know what your practical experience with horns and horn design is. While I have only played with tapped horns for about 6 months, I have 17 years of experience building conventional horns systems. I guess I need to say it once again; you don’t need large Xmax in order to make high SPL with a horn. The horn is an acoustical transformer. The horn does the work, not the driver and its Xmax. You guys may be mis/un-informed about speaker specifications as well. For example, B&C Speakers has an additional specification named Xvar. This indicates the 10% distortion point of the speaker. For the 8PE21 Xvar = 4.5mm. 18Sound only specifies Xmax in mathematical terms derived from the gap depth, top plate thickness, and coil length. They conveniently avoid any distortion figures because they know they would have to build a better product if the truth was known.
(I have real world hands on experience with most brands of speakers. The short of the matter is don’t believe the marketing department’s lies. It’s only true if they can prove it to me in person. Sadly, my experience with 18 Sound products have not impressed.) kstrain knows what he is talking about --> "It is tempting to be attracted by "triple demodulating rings" and the like, but it is worth a check if it really makes a performance difference."
The Xvar of the 8PE21 gives me about 110dB at the listening position, which is too loud for quality listening. I don’t know what you would call normal listening levels, but average continuous for me is 78dB to 82dB at the listening position. I have 28dB of reserve headroom with the 8PE21. Distortion at normal listening levels is virtually non-existent. Lastly, the 8PE21 is NOT exceeding Xmax at normal listening levels in my listening room. It may look like a mid-range to the inexperienced horn designer, but in the hands of a skilled and seasoned horn builder it becomes a woofer with serious bite.
The true reason why there is no subjective difference between my cheap $2 two woofer tapped horn and the 8PE21 horn is proper engineering of the horn. The cheap woofers are arranged in push-pull with one woofer reverse mounted and its polarity is also reversed. This cancels suspension non-linearity and second order distortion. BL factor in relation to excursion is also linearized. If you ran a Dumax test on the push-pull configured $2 woofers the incremental Kms vs. excursion graph would be perfectly centered. That you can’t buy in any speaker at any price. You have to design it into your plan. The very fact that the 8PE21 can perform as well as the push-pull mounted woofers is a testament to the high quality built into them.
There is nothing wrong with chasing the last 10% if you are willing to pay 90% more for it. The diminishing rate of return is very steep. However, if you got money to burn go ahead. I however prefer to spend that money in areas that can make a bigger difference in the quality of my play back system.
I meant bullet proof more in terms of power handling but I wasn't very clear now I've read it again. 
Poly cone and rubber surround would be more durable especially if it's used outdoors, so I guess these would be better if you plan to build a TH for outdoor parties and such like. Pretty much all prosound drivers use the good old paper cone cloth surround for less cone weight, which helps them get their high sensitivity. I think car drivers tend to have lower Fs which helps them achieve their higher output below 40hz, so I'm thinking a car driver is probably the way to go if you want a TH to be flat to 20Hz.
Personally, I don't want or need a TH flat to 20Hz, as my crossover cutsoff below 20Hz anyway, so making a larger box would be a waste.
Poly cone and rubber surround would be more durable especially if it's used outdoors, so I guess these would be better if you plan to build a TH for outdoor parties and such like. Pretty much all prosound drivers use the good old paper cone cloth surround for less cone weight, which helps them get their high sensitivity. I think car drivers tend to have lower Fs which helps them achieve their higher output below 40hz, so I'm thinking a car driver is probably the way to go if you want a TH to be flat to 20Hz.
Personally, I don't want or need a TH flat to 20Hz, as my crossover cutsoff below 20Hz anyway, so making a larger box would be a waste.
kstrain, i just wanted to gather data about different pro audio manufacturers. i do believe that one can build a driver with low and high tech approaches and also have different design goals like spl, low disortion etc. i dont belief that there is a direct connection from tech level to quality, but i take it as an indicator. also, since i am a nerd, i like high tech.
B&C Speakers knows that Xmax is a loose specification. Eminence also knows that Xmax is a loose specification. That is why both independently tried to create a more defined and meaningful specification. Previously, Eminence used a term named X10, this was the 10% distortion excursion point.
If the print in the data sheet is too small, here it is quoted: “For some transducers, the traditional method of specifying the limit of linear cone excursion as the amount of voice coil overhang is very conservative. In such cases, a measure of cone excursion based on the distortion produced can provide more information about how to best utilize a speaker. To this end, X10 is a measure of the one-way cone excursion that causes the speaker’s output sound pressure to contain 10% total harmonic distortion. This measurement is taken at the speaker’s resonant frequency in free air.”
Eminence dropped its use because most people ignored it, or didn’t understand what it quantified. This is unfortunate because it allowed you to know exactly what the distortion threshold of the woofer was. You could model more precisely before building prototypes. While Eminence abandoned this specification, B&C has embraced it and continues to use it under the name Xvar. No other manufacturer that I know of provides this much detailed information about the real world excursion based distortion limits.
Things get very interesting when you begin to compare previous models with current models. I pulled up the new Definimax 4012HO specs beside the discontinued Magnum 12HO. What I find very curious is even through the same motor structure, top plate thickness, coil length, and gap height are used in both models, the stated Xmax is different. The 4012HO is spec’ed at 6.2mm and the Magnum 12HO is spec’ed at 4.8mm. However, things get very interesting when you look at the Magnum’s X10 specification. Magically, they now both have the same Linear excursion, 6.2mm. While I have not confirmed it with Eminence, I believe they are using the X10 standard to specify all their new models. So, as it can be seen, even a trusted company like Eminence is not exempt from playing games with specifications.
This proves once again why practical hands on experience trumps any arm chair engineering. My hands on experience has shown me that B&C products usually exceed their stated specifications. You can at least take the B&C specifications at face value. Eminence products tend to be pretty spot on with their specifications. However, there is some interpretation needed to understand what some of their specifications really mean for real world applications. Ciare products usually meet most of their specifications. Qes and Qts tend to be a little higher than specified, but are within -15%. 18 Sound, well, I’m not even going to discuss that here. As far as the vintage products like Altec, Electro-Voice, University, TOA, Emilar, Gauss, Renkus, Taylor, RCA, and Jensen go, what specs were available tend to be pretty accurate. The biggest inaccuracy I see is Vas is often over stated. Alnico magnets can loose strength. Also, suspension compliance changes over time.
If the print in the data sheet is too small, here it is quoted: “For some transducers, the traditional method of specifying the limit of linear cone excursion as the amount of voice coil overhang is very conservative. In such cases, a measure of cone excursion based on the distortion produced can provide more information about how to best utilize a speaker. To this end, X10 is a measure of the one-way cone excursion that causes the speaker’s output sound pressure to contain 10% total harmonic distortion. This measurement is taken at the speaker’s resonant frequency in free air.”
Eminence dropped its use because most people ignored it, or didn’t understand what it quantified. This is unfortunate because it allowed you to know exactly what the distortion threshold of the woofer was. You could model more precisely before building prototypes. While Eminence abandoned this specification, B&C has embraced it and continues to use it under the name Xvar. No other manufacturer that I know of provides this much detailed information about the real world excursion based distortion limits.
Things get very interesting when you begin to compare previous models with current models. I pulled up the new Definimax 4012HO specs beside the discontinued Magnum 12HO. What I find very curious is even through the same motor structure, top plate thickness, coil length, and gap height are used in both models, the stated Xmax is different. The 4012HO is spec’ed at 6.2mm and the Magnum 12HO is spec’ed at 4.8mm. However, things get very interesting when you look at the Magnum’s X10 specification. Magically, they now both have the same Linear excursion, 6.2mm. While I have not confirmed it with Eminence, I believe they are using the X10 standard to specify all their new models. So, as it can be seen, even a trusted company like Eminence is not exempt from playing games with specifications.
This proves once again why practical hands on experience trumps any arm chair engineering. My hands on experience has shown me that B&C products usually exceed their stated specifications. You can at least take the B&C specifications at face value. Eminence products tend to be pretty spot on with their specifications. However, there is some interpretation needed to understand what some of their specifications really mean for real world applications. Ciare products usually meet most of their specifications. Qes and Qts tend to be a little higher than specified, but are within -15%. 18 Sound, well, I’m not even going to discuss that here. As far as the vintage products like Altec, Electro-Voice, University, TOA, Emilar, Gauss, Renkus, Taylor, RCA, and Jensen go, what specs were available tend to be pretty accurate. The biggest inaccuracy I see is Vas is often over stated. Alnico magnets can loose strength. Also, suspension compliance changes over time.
MaVo said:
This seventeen years of experience led you to use an eight inch driver, which has gross distortion as soon as you use it over 1mm excursion, as a woofer? Maybe we should reevaluate who has to be educated.
You are the perfect example of an arm chair engineer. You spew ignorant simpling speak from you mouth with no substantive experience to validate it. You personify what was, and still is wrong with the Audio Asylum Forum. It is your type that has ran off the more intelligent contributors. Since you have no desire to learn anything and have taken a liking to criticizing everything I have to share, I’ll cease contributing to this thread.
You are right SY, sorry for the sentence about education.
But still, my point stands and is valid: All other things equal, if you can use a driver with bigger linear excursion, you should do so. There lies no benefit in using a 1mm xmax driver as a woofer. You can do so, but you only limit yourself. The benefit of horns isnt limited to midrange drivers.
But still, my point stands and is valid: All other things equal, if you can use a driver with bigger linear excursion, you should do so. There lies no benefit in using a 1mm xmax driver as a woofer. You can do so, but you only limit yourself. The benefit of horns isnt limited to midrange drivers.
Well, seeing so many successful and fascinating experiences about this, I can't help playing with the hornresp and the woofer I have on hand.
It seems not so good. Loud and deep, yes. But what the xxxx of those peaks and dips!
Maybe this can only be used for 80Hz and down with a very very sharp xover....
Can it get any better than this? Or this big dump driver is just a big no go in such application?
This is the data:
It seems not so good. Loud and deep, yes. But what the xxxx of those peaks and dips!
Maybe this can only be used for 80Hz and down with a very very sharp xover....
Can it get any better than this? Or this big dump driver is just a big no go in such application?
This is the data:
Hi,
you are right to suggest that your TH sim indicates that it's use is restricted to ~<=80Hz.
The TH must by design have at least one fold and some are building multi fold versions.
It appears from reports that the folding is reducing the effect of the HF ripples and that an ultra steep Low Pass filter is not required.
The one concern left is whether a single fold and a 4pole filter will attenuate the 86Hz peak shown in your sim.
Comments please?
you are right to suggest that your TH sim indicates that it's use is restricted to ~<=80Hz.
The TH must by design have at least one fold and some are building multi fold versions.
It appears from reports that the folding is reducing the effect of the HF ripples and that an ultra steep Low Pass filter is not required.
The one concern left is whether a single fold and a 4pole filter will attenuate the 86Hz peak shown in your sim.
Comments please?
Personally I think Hornresp does over-exaggerates the peaks and dips a bit (I think it's theoretically very correct). On the other hand that is what the tapped horn is known for, per definition it doesn't have a nice mid response.
For the 2 tapped horns I build up to date Hornresp simulated similar peaks and dips but I suppose the hearing is very forgiving, down low. Crossed over at 120-145 Hz where 80 Hz looked the max, they sounded just fine (24dB/octave LR), tho crossing at 80 Hz is a good idea imo.
The bump at 20 Hz could be decreased by lowering the S3 value. You can also use a 2:1 compression ratio to make the tapped horn smaller and ultimately less efficient if you desire, by applying a similar ratio to the other area's and or length.
Using 1,0 Pi for instance gives a 5-6 dB boost but only under ideal circumstances (very rigid wall) you might find it's 3-5 dB in reality.
To give an idea (both are 2,83V 2,0 Pi):
Bad mid response
Horrible mid response
I think you could refine some aspects and should just build it!
Wkr Johan
G'day JLH
I'm interested to hear you've had bad luck with 18 Sound drivers. I've used many of their drivers, and without exception they have performed to spec. I was using the 15LW1401 in a critical monitoring installation for many years and received nothing but praise for their stunning sound. The 18LW1400 is one of the best in it's class, and has only recently been bettered by the likes of the BMS 18". Their horns and compression drivers work really well too, what is there not to like???
WRT faraday rings in the motor assembly, well I guess it's each to their own. If you don't think they are worth the money, then don't buy them. I guess AIC is worthless too? I personally demand control of the wild Le changes with displacement in all the bass drivers I use. THD/IMD is reduced and if it is done well there is a very real reduction in thermal compression in the loudspeaker driver. For me, this is worth the cost of entry, too. I stopped playing with the budget options years ago, and have never looked back.
Cheers
William Cowan
I'm interested to hear you've had bad luck with 18 Sound drivers. I've used many of their drivers, and without exception they have performed to spec. I was using the 15LW1401 in a critical monitoring installation for many years and received nothing but praise for their stunning sound. The 18LW1400 is one of the best in it's class, and has only recently been bettered by the likes of the BMS 18". Their horns and compression drivers work really well too, what is there not to like???
WRT faraday rings in the motor assembly, well I guess it's each to their own. If you don't think they are worth the money, then don't buy them. I guess AIC is worthless too? I personally demand control of the wild Le changes with displacement in all the bass drivers I use. THD/IMD is reduced and if it is done well there is a very real reduction in thermal compression in the loudspeaker driver. For me, this is worth the cost of entry, too. I stopped playing with the budget options years ago, and have never looked back.
Cheers
William Cowan
i dont see a problem with a debate JLH and mavo, it should just be kept non personal, and i learnt from what he said about xvar as both the woofer and midrange B&C speakers have the same xvar
in fact i contributed and personally agree with mavo, but im only 20 so i dont have anywhere near enough experience to argue, but each to his own at the end of the day
i don't think u should quit the thread over this point
im just loving my horn, just to lazy to paint it and post final pics at the moment, still waiting on a paintbrush
my main thanks goes out to mavo for directing me to this thred in the first place or i would of ended up with 2 passive radiator sub woofers that would have cost twice as much.
would also like to thank tb46 for his interest and help in understanding how to design the thing
in fact i contributed and personally agree with mavo, but im only 20 so i dont have anywhere near enough experience to argue, but each to his own at the end of the day
i don't think u should quit the thread over this point
im just loving my horn, just to lazy to paint it and post final pics at the moment, still waiting on a paintbrush
my main thanks goes out to mavo for directing me to this thred in the first place or i would of ended up with 2 passive radiator sub woofers that would have cost twice as much.
would also like to thank tb46 for his interest and help in understanding how to design the thing
