two 10s or a 15?

what are the advantages or disadvantages of having say two 10s or a single larger 15? sound quality? or bass response?

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tens will be tighter cleaner bass. the 15 will hit the lower notes better but has more "flabby" slower response and not do as well on the "higher" notes. just my opinion. get a pair of tens or 12's if you wont have a mid-bass sub to go with the 15

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Quad L Handyman services

space- a 15 will require a lot, you'll have more wiring options (1,2,4 ohms) with 2 subs, deeper bass with 15"
just a few things to think about

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owner of
Motion Marine & Car Audio
the florida keys

cool, i think ill keep my 10s, was just trying to find a way to make a little more trunk space with a single sub, but in the end i dont think its going to be worth it, ill just have to relocate my amp since i put it in a bad place for space saving! thanks guys

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...and another recent thread that addresses these differences can be seen here.

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Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.

Ketel22 wrote:

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tens will be tighter cleaner bass. the 15 will hit the lower notes better but has more "flabby" slower response and not do as well on the "higher" notes. just my opinion. get a pair of tens or 12's if you wont have a mid-bass sub to go with the 15

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Actually that's another one of those audio myths.  "Woofer speed" isn't effected by mass, but inductance.  Read this link to see why this is true: https://www.adireaudio.com/tech_papers/woofer_speed.htm

Steven Kephart

Adire Audio

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Thank you Steven! Good info! I am glad to see there is somebody out there who can explain things WAY better than I can!

Also, the 10's can go EVERY BIT as deep as the 15, and depending on the configuration of the enclosure, possibly deeper. I had an Eclipse Ti 10 inch driver that played LOWER (noticeably) on it's optimum box than the Ti 12 I presently have. I had a friend of mine at Harman, (in Northridge) Klippel both of the drivers, and we designed optimum enclosures for both of them, and the 12 may have more overall OUTPUT, but the 10 had better EXTENSION. It all depends on how the driver is built.

I would also like to address this "break-in" question that keeps coming up... It is not an engine, there are no friction parts that must be rubbed gently together until they mesh correctly... PLAY IT LIKE YER GONNA PLAY IT, every day of it's life... You ain't gonna hurt it, just 'cause it's "new"! I have never broken in a SINGLE driver my entire life, and no ill has ever befallen me. If there IS any break in, it will only loosen the suspension a little, and maybe give you a little different frequency response, but if this is the case, and you do not want that change, BREAK IT IN, (with your sine wave generator set for the specified Fs of the driver) OUTSIDE OF ANY ENCLOSURE, WITH LOW POWER, (say 10-15 watts, but in no case beyond the linear capabilities of the driver, and you'll hear it when you get to that point) for 24 hours, then test it, and build your enclosure based on THOSE numbers.

OK, enough ranting... off to bed with haemphyst...

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It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."

Ah haemphyst, I believe this is the first time I have disagreed with you.  I understand the controversy about break-in, but I have to say that for high-end loudspeakers a break-in period is imperative.  It's not because of friction, but because of elasticity in the suspension components (the spider and the surround.)  These parts flex, as you know, and right off the assembly line they are "stiffer" than optimum.  Allowing them to be "warmed up" via a break-in period ensures better excursion and more compliance with better efficiency.  I have tested loudspeakers and seen as much as a 3db improvement after break-in, and some larger midrange driverss seem 'warmer" to me (especially soft domes.)

Now, in car audio, most loudspeakers are made with different materials than are high-end home or professional drivers.  Car woofers are designed to handle much higher power (less efficiency) and to withstand the temperature extremes from being outside.  They seem to need a break in period less than do most home systems.

But if your point is that they won't "break" or fall apart without a break-in, then yes, you are correct.  I've never seen that happen unless something else was wrong.  But will they perfrom to their best or sound as good as they can right out of the box?  Not usually.  Break them in before you test the limits or judge the performance too harshly.

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I can't take credit for that paper.  My boss wrote it.  He's a brilliant engineer, and proves it in those white papers (and of course the product he produces).  You should check out the other papers in that section.  I'm sure you will enjoy them.  He get's into stuff like an adjustable Q on a dual voice coil driver, testing different types of RCA's to see which has the best noise rejection, and a description of our XBL^2 motor topology as compared to standard motors.  Here's a quick link: https://www.adireaudio.com/tech_papers/tech_central.htm

And as for the break-in part, I agree with DYohn.  This is becuase we supply a warning with our Brahma's that say to properly break in the driver.  But I personally haven't looked into the subject, so my point of view is strictly based on my boss's recomendation.  I will get back to you on that with more info when I get a chance to ask him about it.

Steven Kephart

Adire Audio

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...but this is why I mentioned the break-in OUTSIDE of an enclosure, before you test it and build the enclosure for it. If you build an enclosure for a driver, pull the driver from the carton, and install it, you are likely going to be disappointed in the response AFTER the suspension loosens up. I also said I never break in a driver, but this is a bit of a mis-statement. I do not break-in a driver after the installation, but before, using the above mentioned method. If you build the enclosure, pull the driver from the package and install it, whether you break it in gently or WFO, it does not matter... the driver/box alignment will be wrong after the break-in period. Basically, all I am saying is "Because the box can't change, but the driver will, if you got a box/driver combo installed, forget the break-in, cause it ain't gonna matter, unless you build another box."

Steven, (have I met you at CES?) I am not certain, but I was thinking that that warning is for break-in outside of an enclosure, not in the box after the install. Also, (and PLEASE do not think I am trying to steal your thunder, I am NOT!) I have been thinking about adjustable Q on drivers for years... actually more along the lines of "passive post-amplification equalization". By driving a single VC in a DVC driver with an amp, and measuring its' response in an enclosure, you can build a semi-adjustable passive tuning circuit hung off the other voice coil, to adjust the damping of the driver selectively, thus, effectively equalizing the response of the driver IN THAT enclosure.   ...it was a pipe dream, and I never sat down to do it... (sounds like MANY of my projects...) Honestly, I like the idea of a simple resistor... much easier to adjust, and no funky calculations, either... but, by selectively EQing the resistance at X frequency, you could adjust the OUTPUT of the driver at just X frequency, where a resistor adjusts the output at all frequencies being fed to the driver, by applying broad-band damping, and attenuation (Qts adjustment).

As an example of my idea, if you have a box/driver alignment with a 6dB hump at 80Hz (blech! sounds like many car stereos today, doesn't it?), by using an RLC network, you can say "this is a lower resistance at 80Hz, therefore the output from the driver at 80Hz will be down by Y dB", but attenuated Y/2 at 40 or 160Hz. Also, an RLC network will give a nice notching ability, and you can build the notch Q right into the network... it is simply a bandpass passive crossover, placed on the second terminals of a DVC woofer. Flexibility come with the various alignments available... 6, 12, 18, 24 dB slopes with Butterworth, Zobel, etc. functions available. A passive circuit will apply selective resistance to the secondary VC, and thusly, apply selective passive damping i.e. equalization.

At least it all works on paper! LOL... And I don't want to see Adire using this idea witout (at a minimum) proper credit!

Thanks for reading this, for those of you that bothered with the whole thing. I know I do go on, but I hope I get my point across effectively.

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It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."

Here's what our Brahma user manual says about break-in:

"Break-in is best accomplished once the driver is installed. The first 2 days of use, keep the volume way down. Over 99% of all break-in problems are not from the driver, but from the setup of the system. Any time you change out any piece of gear in your system – including a driver – there is the chance that wires will be knocked loose, gains/controls bumped and set wrong, etc. Spend the first few days finding all these problems. Only after the system has proven to be very reliable and solid (no cutouts as you go over bumps, well balanced, etc) for a minimum of 48 hours should you begin turning it up."

As for CES, unfortunately I have never been.  I got hired at Adire only a couple months ago.  But I will be at CES next year.  So if you go, look me up. 

Your above idea is intriguing.  I will have to pass it on to my boss to see if it will work right.  It sounds good to me though.  Although no offense to you, but I wouldn't be surprised if he has looked into it before.  IMO we have some of the most intelligent engineers in the industry working for us.  If you haven't read about the XBL^2 motor, I recomend you doing so.  It is rather ingenious.  Also look at our new arachnid spider.  It is the one used on the Parthanon subwoofer found here: https://www.adireaudio.com/Files/Dan/Parthenon/  It keeps the Kms curve perfectly flat.  We rate it's linearity to 10% of K instead of DUMAX's standard 400% of K.  And tolerances per spider are less than .1% rather than the standard 30% tolerances on standard spiders. 

Steven Kephart

Adire Audio

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Wow, I thought I had a pretty good understanding of how car audio worked but you guys are talking so far over my head I feel like Im 6 feet under. Super interesting stuff though.

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double-secret reverse-osmosis speaker-cone-induced high-level interference distortion, Its a killer

thats why i love this site. learning new stuff every day....

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Quad L Handyman services

I believe Tesla (one of my heroes) invented an adjustable impedence voice coil for use in telegraph systems that has been used by Altec Lansing in an adjustable Q loudspeaker.  I'll have to look that up tomorrow at work.  We use some adjustable low frequency drivers in one of our test rooms to create different Q room environments... but that's different from what you're discussing.  Also, take a look at the technology n the KEF Reference Series Model Four, which was an amazing loudspeaker system back about 8 years ago that maintained a single Q number acrosss the entire audible spectrum.  Amazing stuff.

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Isnt the infinity perfect avalible with an adjustable q

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double-secret reverse-osmosis speaker-cone-induced high-level interference distortion, Its a killer

Ravendarat wrote:

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Isnt the infinity perfect avalible with an adjustable q

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Yes it is.  By removing one of the plugs, you make the pole piece smaller saturating it earlier.  This reduces the B field, thereby effecting Qes, and from that Qts.  What they don't tell you is that by lowering the BL, Fb drops which can effect your in car frequency response.  Also efficiency and Re are also effected.

By using a resistor, I don't think as many of the parameters are effected.

Steven Kephart

Adire Audio

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