Better Bass vs Better Room vs Better Driver

[Warpdrv]

Direct match was probably a poor choice of wording, it doesn't output as high, but the distortion isn't all that bad for that driver. Its not a bad choice in driver, for the price. Obviously its not a TC-Sounds, but then again that company is defunct for the time being. I have heard that posssible middle of 09 that we might be seeing Audiopulse drivers becoming available once again - including the LMS (but it will be expensive)

BTW - Make sure you bench test those Axis drivers to make sure they are good, one of the new in box Revo's I got was bad, (voice coil was clanking) and they can't replace it, so I will get a refund. Just a heads up before they are totally out of stock.

 

[highfigh]

Highfigh. The seating position is about 3.5 feet from the back wall. The speakers are 4 feet from the front wall. I don't have much room to play with the position of either because I need room behind the speakers to get between the kitchen and the bedrooms.

Is your sub against the back wall, behind your main speakers? That will cause cancellations if you can't adjust the sub's phase with a continuously variable control. A phase switch won't work in this case. Also, is this a down-firing woofer or direct-firing?

 

[WmAx]

Direct match was probably a poor choice of wording, it doesn't output as high, but the distortion isn't all that bad for that driver. Its not a bad choice in driver, for the price. Obviously its not a TC-Sounds, but then again that company is defunct for the time being. I have heard that posssible middle of 09 that we might be seeing Audiopulse drivers becoming available once again - including the LMS (but it will be expensive)

BTW - Make sure you bench test those Axis drivers to make sure they are good, one of the new in box Revo's I got was bad, (voice coil was clanking) and they can't replace it, so I will get a refund. Just a heads up before they are totally out of stock.

Actually, I am lucky, as my friend has high level signal testing gear/hardware, and has tested them for me, as well as mechanical tested them for several hours.

-Chris

 

[Warpdrv]

Actually, I am lucky, as my friend has high level signal testing gear/hardware, and has tested them for me, as well as mechanical tested them for several hours.

-Chris

Awesome.... I should really invest in a WT3 myself....

But I figured I would at least throw that out there, just in case they were still layin in the box and you didn't get around to testing them out just yet....

At least I know If I don't end up using all my TC/Audiopulse drivers someone will be very happy to acquire them...

 

[WmAx]

Awesome.... I should really invest in a WT3 myself....

But I figured I would at least throw that out there, just in case they were still layin in the box and you didn't get around to testing them out just yet....

At least I know If I don't end up using all my TC/Audiopulse drivers someone will be very happy to acquire them...

Yeah, the WT3 is great. I have one. But like most all testing units, it only does low level signal testing. This fine for most uses. But for further consideration of variables, you need high level signal testing ability. But, a driver like the TC or W7 is so linear in performance and has such low compression and excellent suspension, that it acts very close to the low level signal as compared to high level signal, in the range you would actually use it for music program.


-Chris

 

[fredk]

Fred, is there a budget in mind, are you looking to start up a new build..?
What is the largest size box you can manage...?

I do stuff like this strictly on a cash in hand basis, its a tough economy and I work in automotive. So the answer is, yes I plan on a build, but I have no idea when or how much will ultimately be available. Size is limited by what will fit in my room. I figure thats around 10cf.

In the end, I want a sub that will deliver clean bass down to about 15Hz.

I have looked at the CSS sdx15. CSS and Mach5 are apealing because the are on the same side of the border as me and are both holding Canadian pricing down. If I have to spend $300+ on a driver to get what I want, so be it, but I am not looking for crazy low frequency or monster spl.

If the MJ18 played flatter down to 30Hz, with a low tuning, It would be an ideal candidate (since I plan on two subs down the road). It dosn't

 

[fredk]

you seem to be paranoid about getting 'perfect' performance

I like to think of it as obsessed. Why buy a Ferrari to drive to the corner store for milk when a Hyundi will do just fine.

With the MJ18, I was interested in what percentage of Xmax would be used for the spl levels I was looking at. Even if the driver is only linear through the first 50% of it stated travel, if that is all I used, in my application, it would be good enough at a considerably lower price.

In fact, it looks like that would be the case. I just don't like the way it rolls off all the way from 100Hz with a low tuning.

The other reason I ask so many questions is I like to learn. I have a need/desire to know how and why things work, not just that they do. If I won a million tomorrow, I would probably go back to school and do a technical degree.

 

[WmAx]

I like to think of it as obsessed. Why buy a Ferrari to drive to the corner store for milk when a Hyundi will do just fine.

With the MJ18, I was interested in what percentage of Xmax would be used for the spl levels I was looking at. Even if the driver is only linear through the first 50% of it stated travel, if that is all I used, in my application, it would be good enough at a considerably lower price.

In fact, it looks like that would be the case. I just don't like the way it rolls off all the way from 100Hz with a low tuning.

The other reason I ask so many questions is I like to learn. I have a need/desire to know how and why things work, not just that they do. If I won a million tomorrow, I would probably go back to school and do a technical degree.

Based on BL graphs, the average driver starts to deviate substantially from linearity after roughly 20 percent of it's factory rated x-max, and by 40-50%, severe deviation. An 'excellent' driver would have very linear motor force up to about 75-80% of factory rated x-max, with some moderate, but not severe deviation by 100 percent.

The commonly accepted linear x-max rating that is accurate, should be the point where motor strength decreases by 30 percent. But like amplifier power ratings -- it's all too easy and tempting for a manufacturer to, uhm, exaggerate....

-Chris

 

[fredk]

Thanks Chris. It is info like that which I am trying to dig up. I have seen BL curves on a car audio site that look like an inverted U and contradicted their published specs.

Having worked in marketing for a number of years I understand where the temptation comes from. Lyin... um, spin works remarkably well.

 

[fredk]

Almost forgot. Is distortion expressed as a function of the slope of the BL curve?

 

[highfigh]

I like to think of it as obsessed. Why buy a Ferrari to drive to the corner store for milk when a Hyundi will do just fine.

With the MJ18, I was interested in what percentage of Xmax would be used for the spl levels I was looking at. Even if the driver is only linear through the first 50% of it stated travel, if that is all I used, in my application, it would be good enough at a considerably lower price.

In fact, it looks like that would be the case. I just don't like the way it rolls off all the way from 100Hz with a low tuning.

The other reason I ask so many questions is I like to learn. I have a need/desire to know how and why things work, not just that they do. If I won a million tomorrow, I would probably go back to school and do a technical degree.

Yeah, but a Hyundai won't get you anywhere with the hot checkout girl.

One thing that can't be ignored- you can make a subwoofer that performs perfectly in an anechoic space but once it goes into a room, that all goes out the window. The room's dimensions will cause a great woofer to sound like it's terrible and sometimes, a smaller woofer works better. High excursion can help but the way it all works together is what really matters most.

 

[fredk]

Well, after a lot of intensive reading, some modeling and some thinking, things are starting to come together.

Improving the room comes first. Comments from TLSguy early in the thread made me realize that with the extension I am getting down to 22Hz, I am getting good coverage of most of the bass a pipe organ plays. Cleaning up the room will offer a lot of bang for the buck.

It also turns out that the huge peak I have at 52Hz is almost exactly the same in the entire listening area (did more measurements last night) and is an exellent candidate for equalization. This will clean up my bass a LOT.

On the driver side, the choice is not so clear. It seems like there are a series of tradeoffs to be made as you slide down the price/performance continuum.

The 12" drivers, even those of above average performance, are at the bottom of the scale for my application because I do want more bottom end extension. They might work, or might not. I may still end up with something like a Kappa Perfect 12 because they seem to come up used frequently. If the price is right, I can afford to experiment and sell the driver if I don't like the results.

On the top end, I just won't use the excursion and high spls of a driver like the MaelstormX

The Mach5 MJ18M also sits on the edge. It will give me a little more bottom end extension to reach solidly into the teens, but isn't flat quite low enough. It would probably work fine for music, but may fall a little short for movies.

Given where I live and current exchange rates, the CSS 15SDX is probably the best choice as I know it will deliver the frequencies and volumes I am looking at with a little extra headroom to spare.

It is going to be a while before I have the money to build and depending on the $ I can come up with, things may change.