10" GRS subwoofers showed up today...

[Pete Basel]

Re: 10" GRS subwoofers showed up today...

Near field? Do you mean as close as you can get to the cone, less than an inch?
I'd need to see .5 m - 1m for any meaningful results.

Thanks for sharing

[johnnyrichards]

Re: 10" GRS subwoofers showed up today...

Near field? Do you mean as close as you can get to the cone, less than an inch?
I'd need to see .5 m - 1m for any meaningful results.

Thanks for sharing

Baffles are cheap and so are the drivers

I will not be doing far field measurements due to their intended use well below the point where far field tells us anything useful, actually.

That being said, I do not post measurements of that sort, anyways. People always complain about the information, so I just avoid that headache altogether. Measurement gear is cheap.

[donradick]

Re: 10" GRS subwoofers showed up today...

That woofer looks pretty outstanding for the price. I may have to get a couple of pairs.
Thanks Johnny!

[Beau]

Re: 10" GRS subwoofers showed up today...

I'd like to see how that 12" sub would do.

It looks like it would have to be sealed, but maybe OB would be an option?

[SPLEclipse]

Re: 10" GRS subwoofers showed up today...

Glad to see someone is giving these a shot!

Would you do me a huge favor an measure the mounting depth from the back of the flange to the end of the backplate bump? PE lists mounting depth as 5" but based on eyeballing it looks to be a bit more shallow than that. Depth is somewhat important for my intended usage (IB kickpanels in my car). Thanks and Merry Christmas!

[Pete Schumacher]

Re: 10" GRS subwoofers showed up today...

Near field? Do you mean as close as you can get to the cone, less than an inch?
I'd need to see .5 m - 1m for any meaningful results.

Thanks for sharing

Just curious, but what can you get from .5m that you can't get from 1"?

[Jay1]

Re: 10" GRS subwoofers showed up today...

Just curious, but what can you get from .5m that you can't get from 1"?

Wouldn't 1" only be valid up to a few hundred hz?

[Pete Basel]

Re: 10" GRS subwoofers showed up today...

Wouldn't 1" only be valid up to a few hundred hz?

Yes, exactly, anyone who doesn't get this should read Keele's paper, #6 here:

http://www.xlrtechs.com/dbkeele.com/papers.htm

Figure 10 is for a 4.5" cone and significant deviation between nearfield (b) and
farfield halfspace (c ) starts at about 1.5 KHz, a cone twice as big would start
at half that frequency or about 750 Hz. See Figure 8 for an 8" woofer where the
error starts at about 800 Hz, but halfspace farfield is not shown so you have to
correct for that difference.

I'd like to know, with reasonable accuracy what this driver does at least to 1 KHz,
preferably to 5 KHz - I'd like to see the shape of the roll-off.

We have been through this before, I think on this forum, I'd have to do a search.

[thekorvers]

Re: 10" GRS subwoofers showed up today...

Yes, exactly, anyone who doesn't get this should read Keele's paper, #6 here:

http://www.xlrtechs.com/dbkeele.com/papers.htm

Figure 10 is for a 4.5" cone and significant deviation between nearfield (b) and
farfield halfspace (c ) starts at about 1.5 KHz, a cone twice as big would start
at half that frequency or about 750 Hz. See Figure 8 for an 8" woofer where the
error starts at about 800 Hz, but halfspace farfield is not shown so you have to
correct for that difference.

I'd like to know, with reasonable accuracy what this driver does at least to 1 KHz,
preferably to 5 KHz - I'd like to see the shape of the roll-off.

We have been through this before, I think on this forum, I'd have to do a search.

I thought we were talking about a SUBwoofer here!

[Jay1]

Re: 10" GRS subwoofers showed up today...

I thought we were talking about a SUBwoofer here!

If it's clean enough up top it could be crossed to a tiny mid or full range driver. I dont see what the harm in having this info is?

[johnnyrichards]

Re: 10" GRS subwoofers showed up today...

Too cold to cut anything new right now, and even more too cold to make a baffle big enough to get the measurements that are desired. I have some cabinets out there that will fit these with some simple modifications, but it is not #1 priority at the moment. I just wanted to let people know that as a budget subwoofer, they bring a lot to the table. In fact, for not much more than the cost of a single RS265 you can buy ten of these and have a LOT of fun.

The nearfield will tell me everything I need to know about the driver. But just looking at the impedance curve, I would bet it to have a smooth enough roll-off to make for simple crossovers, and it is probably usable to 1K or so. The inductance curve doesn't start making its hockey stick shape until around then, and even then the impedance rise is better controlled than a lot of cheaper drivers.

In a few months, I may have weather and/or time and/or inclination to indulge in some "IEC" testing but it really isn't up my alley to do that kind of thing.

[thekorvers]

Re: 10" GRS subwoofers showed up today...

If it's clean enough up top it could be crossed to a tiny mid or full range driver. I dont see what the harm in having this info is?

I did not say there was any harm in having additional info.

However I do find it rather condescending for Pete Basel to imply that Pete Schumacher does not know what he is talking about and that that is because of a lack of knowledge, to be remedied by reading the article he linked to.

Having observed Pete Schumacher and his contributions over the years, I strongly suspect that he knows exactly what he is talking about and that his statement originated in the thought that we were discussing a SUBwoofer and it's capabilities. Hence my post. I am also sure that Pete Schumacher is very much aware of the necessity to modify his testing procedure when measuring higher frequencies.

[Jay1]

Re: 10" GRS subwoofers showed up today...

I did not say there was any harm in having additional info.

However I do find it rather condescending for Pete Basel to imply that Pete Schumacher does not know what he is talking about and that that is because of a lack of knowledge, to be remedied by reading the article he linked to.

Having observed Pete Schumacher and his contributions over the years, I strongly suspect that he knows exactly what he is talking about and that his statement originated in the thought that we were discussing a SUBwoofer and it's capabilities. Hence my post. I am also sure that Pete Schumacher is very much aware of the necessity to modify his testing procedure when measuring higher frequencies.

I agree and that's why I posed my question to Pete

[Pete Basel]

Re: 10" GRS subwoofers showed up today...

Baffles are cheap and so are the drivers

I will not be doing far field measurements due to their intended use well below the point where far field tells us anything useful, actually.

That being said, I do not post measurements of that sort, anyways. People always complain about the information, so I just avoid that headache altogether. Measurement gear is cheap.

I agree that if all you care about is subwoofer use then yes nearfield is probably
fine. I have lots of measurement tools, don't have any current use for this woofer
so I won't be buying one.

[Pete Basel]

Re: 10" GRS subwoofers showed up today...

This driver could be used in other applications if it has a smooth clean response
at higher frequencies.
I'm not going to discuss the near field far field thing again, we've been through
this before.
I respect the fact that Johnny doesn't want to do any more testing, that's fine it
was just a suggestion.