I hate cars

This is just a theory or even a guess so bear with me.

I've always regarded a lighter sub or midbass having more detail in the bass as a myth. Many other semi-educated audiophiles do, at least it seems that way on the internet. I no longer have my mind made up either way.

My IB15s are extremely light for a 15" sub. The moving mass is only 152g and 830cm^2 of cone area which is on the large side for a 15". In fact, there are many 10s that have a higher moving mass than these 15s. These subs have always done it all, they dig incredibly low with authority but they're "quick" "tight" "snappy", and even detailed and articulate for a sub. These subs play everything great, nothing is missed, no double or triple drum beat, nothing. Is it the low Mms or the very low inductance or something else...

I always thought and still do that the motor strength (Bl) makes up for the weight of heavier subs when it comes to the "quickness". The Qts and more importantly Qtc determines the "quickness" and "tightness" and the overall response. But maybe additional motor strength can't make up for the potential loss of detail of a heavy cone.

Since going with the 10s in the doors (small 10s, more like 9s before someone says something) I've noticed something different. With a highpass of 63hz, an area the subs used to cover with the 6.5s up there, there seems to be more detail in the lower bass that the 10s cover. These 10s have a low 36g moving mass, low for a 10" or a 9". They use a 4" voice coil so I can only imagine how light the actual cone is.

I've noticed the 60hz area to be more articulate now. I don't think I would even call it "quicker" but I swear there's more detail now. The sub bass and bass range is just perfect right now. I never would have imagined that the 20hz-100hz range could be so accurate and articulate. I never realized there was supposed to be detail in this area but you can hear so much more going on now. So the question is, will a lower Mms allow a speaker to have more detail than a heavier Mms speaker? Many people run their subs pretty high into the midbass area as I used to for a long time but are you losing some detail when you do this?

I used to always say to run the subs up high to get more dynamics that a 6.5" just can't physically produce at higher volumes and I still think that might be the better compromise but maybe I accidentally found another advantage of having a large midbass and being able to cross it lower, additional detail in the bass range. Anyone agree, disagree?

rich20730

I read through this entire thread on DIYMA recently. The article linked in the first post seems to make sense to me, but I admit that there are parts that I don't completely understand. If Mms does in fact have an effect on detail/woofer speed/transient response, then someone smarter than me should be able to point out some flaws in the article.

http://stereointegrity.com/docs/WooferSpeed.pdf

Another way to approach the issue would be to explore what other factors could contribute to the bass sounding more detailed with the MW182's covering the bass region that your 15's used to cover.

A couple of possibilities that come to mind:
1. Location. The upper bass content is now actually coming from the front of the car instead of behind you leading to less localization issues and better blending of the sub and midbass frequencies.
2. The subs being mounted behind the back seat blocks some of the higher frequency bass from coming through to the listening position.
3. Inductance. What is the inductance of your 15's compared to the 10's?
4. Lower crossover point.

I hate cars

I agree on every point. The back seat definitely blocks some frequencies but I have played the subs up to 2khz before and they do female vocals surprisingly well. It's definitely possible that the seat blocks enough of the "details" that the lower bass covers them up, especially coming from behind me. Putting the arm rest up makes it much worse from 60hz and up.

It's possible if I would have crawled in the back seat and listened carefully, those details might have been there.

Le is .18mh on the subs, midbass is .5mh. My midrange is .19 lol. These subs have excellent inductance performance, on par with some midranges. They're -3db at 2.2khz and -6db down at 3.9khz.

I'm not really arguing the quicker or faster argument but rather guessing that a heavy cone *might* not give as much detail and I'm not talking a couple grams, I mean the difference between say the 152g 15" and 36g 10".

What got me thinking lately is on the MSS board one of the well respected members mentioned that most widebanders can't be as articulate as a dedicated midrange or tweeter because they have to be heavier in order to produce the low end material without too much distortion.

I'm still up in the air about this, your points are appreciated.

jda123

I have no real answers based in anything other than my own observations and experience (which nobody should take seriously), but an appropriately motored sub, even being heavier to move, should be the same. This is where academia and the real world don't mix, IMO. Manufacturing price points and trying to make money have a lot of companies skimp on motors... and if their assembly is too heavy, then they sound "slow." This is especially true when companies use the same motor on a 15 that barely works on a 8 or 10. Some companies use a 15" motor on an 8, and that works.

...so academically, I don't think that it matters either way if you assume that the motor is appropriate. In reality, it is no coincidence that better drivers are lighter and the motors are heavier since the builders know what it takes to make quality sound waves.

Like a lot in car audio, this is both a myth, and not a myth, depending on which level of academia or reality you are in at the moment, IMO. You see people get laughed at for saying that 8s are "faster" than 15s, but in most lower end subs (which 95% of the public has experience with), the motor on the 15s is probably too weak so that the manufacturer, middle man and retailer can all make a profit... so they are not wrong, in reality, for saying that the subs are "punchier" and "faster," but it is wrong in academia where assumptions come into play.

Then, I can also argue the usefulness (and reliability) of the manufacturers numbers regarding QTS, QTC, BI, efficiency, etc. since we have all had speaker that we thought would perform one way, yet sound totally different.

The main difference that I see is gas (watts) to move the weight. I don't care that my 4700 pound steel tank needs a 500+ cubic inch big block to get to 11 seconds. If you need small amps, then this might be a bigger concern, but this does not bother me.