Fiddling around on the net the other day looking for some beefy midwoofers to use I stumbled across something that I had not realized before. Now I know how touchy this subject is with some believing and some not, but bare in mind the possibities.
I was doing some adjustments on my stereo after switching from the three 10" subs back to the single Dayton. In retuning I noticed I had some noise in one of the front door midbass's. Went to switch them with some 8 ohms I had been playing around with and they was making some noise as well. I proceeded to go to my storage and pull out a brand new pair of the first set, but out of curiosity I wanted to take some measurements first.
Out of the box the Audax's were measuring a Qts of around .55 or so with a corresponding Fs of 57hz. I thought this was odd as the manufacturer specs state differently. So I took out one of the older ones and took a reading. It's Qts were around .35 or so with Fs around 33 as well. Strange!!!
Since the older ones were getting replaced I neatly removed the surround and cone to see if there was voice coil damage. To my surprise there wasn't any. But what I did find was the cone was rather a tad bit thinner than I first thought and the spider was definitely of a thin (cheap) material. I concluded that the cheap spider was allowing the woofer to "snap" in it's excursion causing the bad sound. I was a bit rough on them but, I don't think I bottomed them out as the coil bobbin was intact..
It also occurred to me that because of the cheaper materials, break-in changes was more apparent, perhaps designed that way. Still to go from .5 to .3 is major in my books and possibly suggests a lack of quality in construction & materials.
I was going to use the spares but now I think I need to wait for something a little more tougher... THINK
Ash,
Replies (8)
swez on 03/30/2008 20:03:48
This almost makes one wonder if the older speakers were made with inferior materials and PE got a large lot of them at bargain basement prices and sold them cheap? (Out lots or non-spec speakers that were rejected from Audax for QC reasons and sold to various Disty's anyway???)
Swez
Ash on 03/30/2008 20:42:53
That could be true.... This the first time that I had tested a new one out of that lot so it is hard to say. Manufacturers specs (from Audax site) are in line with the used drivers so that kind of negates it somewhat. It is also possible that a specs were drawn from drivers fully broken in, which could make their QC more accurate. Hard to tell now that Audax is gone.
I believe with nominal usage the new drivers will yield about the same specs as the old. One has to figure that if a break-in period is viable it is going to happen with less resilient materials used. The spider on these surely isn't the toughest around and can totally affect all mechanical parameters. Some electrical parameters will be as well since compliance will change.
Wonder how many speakers on the market are tested before or after..... Since some don't think it is real would they?
Ash on 04/6/2008 19:16:17
Well, despite the long tussle with the Audax, I decided to move on. I won't put them down for they do have a place, just not the capabilities that I'm looking for. Too bad though, because they are nice drivers with a lower powered setup. Plus to add to the fact that they are no longer making them, that doesn't help the diy crowd.
Maybe I'll find another use for them like in my sons ride when he gets one hopefully this summer. I've got just enough components to do one or two 3-way setups that will be just a step above stock.
In the meantime I did some heavy research and opted for the Dayton RS180's. Should be a perfect match sonically for the HO 10". This time I'll be sure to test them before and after to see if break-in is a true factor and of how much.
Ash on 04/12/2008 19:57:53
The Dayton mids have arrived and it will probably be a little while before they're installed. I did test them after a small evalution of their build.
There definitely has been some thought into their design. The baskets are cast with much larger windows for the cone to breath. The cones are very stiff (metal properties attribute of course), but they are quite small despite the large basket diameter. These are stated as being a 7" driver, yet when compared to maybe a 6.5" or 6.75" driver, the cone area is pretty much the same. Not much gain in that.... The 6" version would have been a no go as it would probably wound up a 5.5".
The magnets are quite heavy, but not too bulky for door installs. Seems like the 60 watt thermal handling should be more with it's weight. No rear venting as there is a hole but is blocked off internally possibly with a shorting ring, The tinsel leads are glued and/ or stitched to the outer edge of the spider. Not sure if it will affect throw, but at least lead slapping won't be a problem.
Parameters were off with P.E.'s site as stated Qts is supposed to be .40, but tested .54 on both drivers. Vas is around 1.4 ft (.6 ft^3 higher). 40hz Fs tested on spot as well as sensitivity. All could change once the suspension is loosened up, but I hope not.
With those specs it should make a nice IB midbass bandpassed between 80-250hz. Before I can confirm this I will have to do some minor cutting on the baffles and door skins as they were never really meant to hold speakers. The Audax just so happen to fit in the access holes with the use of some mdf baffles. Weird how the holes just so happen to be in the right place for a lower door install....
swez on 04/13/2008 09:57:35
Hey Ash, can these T/S parameters be run when the speakers are installed and had some break in time? (W/o removing them from the doors) It would be interesting to see if any measured parameters change with time and in what direction.
Swez
Ash on 04/13/2008 12:21:41
An impedance sweep can be done to see how the doors are affecting the response. As far as full parameters, they would have to be removed as I like to test Vas with weight (grams) rather than sensitivity or a test box. More reliable and pretty simple. Won't be a pain to remove them so as soon as I get some time on them I'll do that and keep you posted.
Ash
swez on 04/13/2008 17:44:55
As you wish Ash. It's nice that you can do these tests and I find them very interesting too. When you can, as you can...
Best regards,
Dave
Ash on 04/13/2008 19:47:04
In my learnings from a while back (still learning) it was always said not to trust manufacturer specs. Now that I have actually started testing them it's amazing how far off the specs can be. I wonder how much QC is overlooked in these facilities as they churn out mass numbers. I know in the plant that I work in, you'd be surprised!
You could say that I'm kinda on a "Bose mission" so to speak. Still trying to find the truth to building a better system for cheap, but it's getting hard to do because the market keeps changing. Sources aren't as good as 10 years ago, and prices for even the cheap stuff has gone up.
I was doing some adjustments on my stereo after switching from the three 10" subs back to the single Dayton. In retuning I noticed I had some noise in one of the front door midbass's. Went to switch them with some 8 ohms I had been playing around with and they was making some noise as well. I proceeded to go to my storage and pull out a brand new pair of the first set, but out of curiosity I wanted to take some measurements first.
Out of the box the Audax's were measuring a Qts of around .55 or so with a corresponding Fs of 57hz. I thought this was odd as the manufacturer specs state differently. So I took out one of the older ones and took a reading. It's Qts were around .35 or so with Fs around 33 as well. Strange!!!
Since the older ones were getting replaced I neatly removed the surround and cone to see if there was voice coil damage. To my surprise there wasn't any. But what I did find was the cone was rather a tad bit thinner than I first thought and the spider was definitely of a thin (cheap) material. I concluded that the cheap spider was allowing the woofer to "snap" in it's excursion causing the bad sound. I was a bit rough on them but, I don't think I bottomed them out as the coil bobbin was intact..
It also occurred to me that because of the cheaper materials, break-in changes was more apparent, perhaps designed that way. Still to go from .5 to .3 is major in my books and possibly suggests a lack of quality in construction & materials.
I was going to use the spares but now I think I need to wait for something a little more tougher... THINK
Ash,
Replies (8)
swez on 03/30/2008 20:03:48
This almost makes one wonder if the older speakers were made with inferior materials and PE got a large lot of them at bargain basement prices and sold them cheap? (Out lots or non-spec speakers that were rejected from Audax for QC reasons and sold to various Disty's anyway???)
Swez
Ash on 03/30/2008 20:42:53
That could be true.... This the first time that I had tested a new one out of that lot so it is hard to say. Manufacturers specs (from Audax site) are in line with the used drivers so that kind of negates it somewhat. It is also possible that a specs were drawn from drivers fully broken in, which could make their QC more accurate. Hard to tell now that Audax is gone.
I believe with nominal usage the new drivers will yield about the same specs as the old. One has to figure that if a break-in period is viable it is going to happen with less resilient materials used. The spider on these surely isn't the toughest around and can totally affect all mechanical parameters. Some electrical parameters will be as well since compliance will change.
Wonder how many speakers on the market are tested before or after..... Since some don't think it is real would they?
Ash on 04/6/2008 19:16:17
Well, despite the long tussle with the Audax, I decided to move on. I won't put them down for they do have a place, just not the capabilities that I'm looking for. Too bad though, because they are nice drivers with a lower powered setup. Plus to add to the fact that they are no longer making them, that doesn't help the diy crowd.
Maybe I'll find another use for them like in my sons ride when he gets one hopefully this summer. I've got just enough components to do one or two 3-way setups that will be just a step above stock.
In the meantime I did some heavy research and opted for the Dayton RS180's. Should be a perfect match sonically for the HO 10". This time I'll be sure to test them before and after to see if break-in is a true factor and of how much.
Ash on 04/12/2008 19:57:53
The Dayton mids have arrived and it will probably be a little while before they're installed. I did test them after a small evalution of their build.
There definitely has been some thought into their design. The baskets are cast with much larger windows for the cone to breath. The cones are very stiff (metal properties attribute of course), but they are quite small despite the large basket diameter. These are stated as being a 7" driver, yet when compared to maybe a 6.5" or 6.75" driver, the cone area is pretty much the same. Not much gain in that.... The 6" version would have been a no go as it would probably wound up a 5.5".
The magnets are quite heavy, but not too bulky for door installs. Seems like the 60 watt thermal handling should be more with it's weight. No rear venting as there is a hole but is blocked off internally possibly with a shorting ring, The tinsel leads are glued and/ or stitched to the outer edge of the spider. Not sure if it will affect throw, but at least lead slapping won't be a problem.
Parameters were off with P.E.'s site as stated Qts is supposed to be .40, but tested .54 on both drivers. Vas is around 1.4 ft (.6 ft^3 higher). 40hz Fs tested on spot as well as sensitivity. All could change once the suspension is loosened up, but I hope not.
With those specs it should make a nice IB midbass bandpassed between 80-250hz. Before I can confirm this I will have to do some minor cutting on the baffles and door skins as they were never really meant to hold speakers. The Audax just so happen to fit in the access holes with the use of some mdf baffles. Weird how the holes just so happen to be in the right place for a lower door install....
swez on 04/13/2008 09:57:35
Hey Ash, can these T/S parameters be run when the speakers are installed and had some break in time? (W/o removing them from the doors) It would be interesting to see if any measured parameters change with time and in what direction.
Swez
Ash on 04/13/2008 12:21:41
An impedance sweep can be done to see how the doors are affecting the response. As far as full parameters, they would have to be removed as I like to test Vas with weight (grams) rather than sensitivity or a test box. More reliable and pretty simple. Won't be a pain to remove them so as soon as I get some time on them I'll do that and keep you posted.
Ash
swez on 04/13/2008 17:44:55
As you wish Ash. It's nice that you can do these tests and I find them very interesting too. When you can, as you can...
Best regards,
Dave
Ash on 04/13/2008 19:47:04
In my learnings from a while back (still learning) it was always said not to trust manufacturer specs. Now that I have actually started testing them it's amazing how far off the specs can be. I wonder how much QC is overlooked in these facilities as they churn out mass numbers. I know in the plant that I work in, you'd be surprised!
You could say that I'm kinda on a "Bose mission" so to speak. Still trying to find the truth to building a better system for cheap, but it's getting hard to do because the market keeps changing. Sources aren't as good as 10 years ago, and prices for even the cheap stuff has gone up.
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