Dayton RSS315HF-4 12" Subwoofer

[Steve81]

Does this show up in any of the measurements from Data Base?

I have had a long term frustration over not being at all happy with many of the subwoofers that are considered very good by most here. I have no idea if it falls back to the Q values, but would like to investigate it further.

Lets consider two systems from DB, one using a relatively high Q driver (RE XXX) in an enclosure that's way too small for it:
http://data-bass.com/data?page=system&id=92&mset=99
and one very low Q driver (Rockford Superwoofer):
http://data-bass.com/data?page=system&id=125&mset=137

The Qtc of the RE XXX system is over the 1.0 mark, while the Qtc of the Rockford system is under 0.5. You can see the obvious differences in FR and some stored energy around the hump of the RE XXX in the waterfall chart.

The discussion of the Rockford system on that forum is interesting, as Josh replaced his old RE XXX system with a Rockford setup, and he offered his thoughts on that comparison:
http://data-bass.ipbhost.com/topic/496-rockford-fosgate-t3-19-discussion/

 

[TLS Guy]

Does this show up in any of the measurements from Data Base?

I have had a long term frustration over not being at all happy with many of the subwoofers that are considered very good by most here. I have no idea if it falls back to the Q values, but would like to investigate it further.

Hi Kurt,

To put it simply, the situation with the Qts of any type woofer or driver to be used as a woofer in a box, as per my own experience, is as follows:

If the driver is to be used in a ported enclosure and you want it to have a very good low frequency response, the woofer should have a low Fs and a Qts ideally between 0.4 and 0.45.
On the other hand, if the driver has a low Fs but its Qts is around 0.2-0.25 for instance, its low frequency cutoff will be appreciably higher, unless you install it in a huge box. In the big cabinet, it will lose some of its efficiency.
As for sealed enclosures, higher Qts are desirable but you lose in efficiency and you get higher distortion levels. IMO, the only advantage is that the driver can be installed in smaller boxes.

Cheers,

André[/QUOTE]

You are shooting to high. I think you are used to somewhat over resonant reproduction.

This is the Sub driver Saul Linkwitz designed for SEAS. Qts is 0.27 and he uses it open baffle. So system Q of that system is 0.27!

 

[shadyJ]

Hey, I offered the caveat in the beginning of my post that the difference could be purely situational with using the same box. Some drivers work better in smaller boxes than others do. The surround on the RSS315 is measurably smaller on the RSS than the UM. Xmax is less, and the cone mass is substantially less just for starters. I have no reason to like one over the other since I own both and nothing to prove otherwise, except perhaps, with regard to efficiency in smaller spaces, where one can not feasibly put the larger, ideal vented enclosure for specific types of subwoofers in their room, when all they need to do with it is listen to music.

But in the time it took to switch drivers in the same cabinet, which was just under 10 minutes, I noticed a rather remarkable, audible and musical difference.

The price difference between the two is not all that great. Why would they make two different styles of subwoofer drivers if both should perform the same? Dayton labels this one for "High Fidelity" (HF) in it's model designation. Apparently, the tradeoff is that it's not perhaps the all around best for HT as well, compared to the UM.

A further observation being, the 12" Eminence Delta Pro-12A in the Tempests is also cleaner for musical bass down into the 40hz area and with mid bass, to where I was running them full range because of it and just using the UM for 55hz and below and well subdued at that for best overall bass performance.

As I said, for the same frequency response. Swapping the driver in the same cabinet will likely produce a different response curve.

 

[shadyJ]

Lets consider two systems from DB, one using a relatively high Q driver (RE XXX) in an enclosure that's way too small for it:
http://data-bass.com/data?page=system&id=92&mset=99
and one very low Q driver (Rockford Superwoofer):
http://data-bass.com/data?page=system&id=125&mset=137

The Qtc of the RE XXX system is over the 1.0 mark, while the Qtc of the Rockford system is under 0.5. You can see the obvious differences in FR and some stored energy around the hump of the RE XXX in the waterfall chart.

The discussion of the Rockford system on that forum is interesting, as Josh replaced his old RE XXX system with a Rockford setup, and he offered his thoughts on that comparison:
http://data-bass.ipbhost.com/topic/496-rockford-fosgate-t3-19-discussion/

Since we are discussing drivers alone, I think the cabinet of the XXX makes that a bad example. Put it in a larger cabinet and you will get a much smoother response. It will still have a high end that is rolled off relatively soon compared to the Rockford Fosgate driver or anything else that has a low Q.

 

[KEW]

Since we are discussing drivers alone

Maybe it is not relevant to the rest of your comment, but I think we are talking about how a specific characteristic of the driver effects the sound of the system it is used in.
This thread started with MrBost swapping drivers in the same cabinet and Q was offered as an explanation of the difference he heard.

 

[MrBoat]

I commend Mr Boat on his experiment which has drawn attention at least on these forums to a very important issue regarding speakers.

Also as a budding speaker builder, he has experimented with full range drivers. I would bet that the frequency response is far from perfect, but I think through it all he has detected the harm that crossovers cause.

One of the basic points of design of my reference speakers, is that much of the crossover design is very much a sleight of hand.

My years of using full range drivers were truly formative. I think every designer should have played about with full range drivers. It is highly educational. I was lucky that I had easy access to Ted Jordan and especially Donald Chave of Lowther, who was nearby in my formative years.

Full range drivers is just another way. There's some pleasing things to be found with that approach. I don't mind being caught stepping outside of the measurements and letting my ears decide for a more personal experience. I'm not out to entertain anyone else most times, so I don't have to adhere to popular, broad range generalizations. Still, every single person that walks thru here or spends a bit, remarks how wonderful it sounds, certainly compared to what they get a chance at most days.

I have a cut on now where a piano and a xylophone are sort of dueling back and forth and crossing each other on matching notes. It's absolutely brilliant through these odd little speakers. Violin, you can almost sense the friction between the bow and the strings, right down to the texture of the hair the bow is made of. Horns that make me get up out of my chair sometimes and physically walk thru it even though it's everywhere. The thing about it is, I am not familiar with this music. This is just random things that are happening. Steel drums just came out of nowhere. I was not expecting it and. . . .all I can say is; "wow."

I am going to be at this full range driver treat for a spell. God help me if it gets better than this.