lighten up some subs

[Jeff Babcock]

Re: lighten up some subs

Originally Posted by Alan Sledzieski
Lab 15 with a sensitivity of 88.5 db, this will be interesting, let us know how it works out.

The sensitivity number does not always "apply" when you horn load a sub.

Alan, if something doesn't make sense to you, instead of publicly rejecting the idea, why not ask a question? Contrary to what you might think, asking questions is not a sign of weakness......

 

[LiamSmith]

Re: lighten up some subs

So, you guys are saying the lab15 driver has different physical dimensions to the OEM driver?

 

[Tim McCulloch]

Re: lighten up some subs

So, you guys are saying the lab15 driver has different physical dimensions to the OEM driver?

What we're saying is "make sure the damn thing will fit." Nobody is saying it won't, but we don't have access to the specs of the OEM driver to say yes or no.

 

[LiamSmith]

Re: lighten up some subs

Ah, thanks tim. I bit the bullet on the lab15. I'll report back to you guys when they arrive.

 

[Caleb Dueck]

Did you ask Yorkville about the Lab15 first?

 

[Alan Sledzieski]

Re: lighten up some subs

The sensitivity number does not always "apply" when you horn load a sub. There are many other things to consider. A higher sensitivity driver does not automatically mean it will be louder-in a horn. It may be louder in a front loaded situation (which is where the number comes from)-but in this case, that is not where it is being used.

Look at the LAB SUB-that uses a pair of the LAB12" drivers. The drivers by themselves have a very low sensitivity (upper 80's if I remember). But when you put them in a PROPERLY designed horn (designed for those particular drivers), the sensitivity jumps WAAYY up. Like to the mid 100's.

Proper horn loading can be a very good thing.

Thanks,

But would it make sence to use a driver that's 98 db and need a lot less amp to get the same output?

 

[Caleb Dueck]

A subwoofer with higher sensitivity, yes; our point is that driver sensitivity doesn't mirror sub sensitivity.

 

[Alan Sledzieski]

Re: lighten up some subs

A subwoofer with higher sensitivity, yes; our point is that driver sensitivity doesn't mirror sub sensitivity.

So if you put a 88 db driver in a box, then a 98 db driver in a box, they will have the same output for given input?

 

[Tim McCulloch]

Re: lighten up some subs

So if you put a 88 db driver in a box, then a 98 db driver in a box, they will have the same output for given input?

There are other T/S parameters that come into play; those determine the suitability of a given driver for a particular loading. Many of the drivers that are happy in horns have relatively low electrical sensitivity.

So while in context, yes a driver with 10dB more sensitivity would take less voltage to reach Xmax, there is the likelihood that it would destroy itself physically (horns do not exhibit equal pressure on each side of the cone) or exhibit poor acoustic performance with horn loading. Ivan or Art can explain...

 

[Bennett Prescott]

Re: lighten up some subs

So if you put a 88 db driver in a box, then a 98 db driver in a box, they will have the same output for given input?

At what frequency is the sensitivity measured? I guarantee you it's not 40Hz. If the two drivers have different sensitivities at 1kHz but the same at 40Hz, well... I'll take the one with the lower sensitivity! Less to EQ out.

 

[Caleb Dueck]

The focus with horn subs is first the horn, then secondarily on the best driver- for that particular horn.

This is why I asked if the manufacturer had been contacted first - they can tell if 'xyz super driver' will even work, much less work better - however that is defined.

Caleb

 

[Ivan Beaver]

Re: lighten up some subs

Thanks,

But would it make sence to use a driver that's 98 db and need a lot less amp to get the same output?

There is A LOT more at play than a simple single number.

I remember when one light bulb turned on-decades ago.

I was running a lot of JBL scoop cabinets. I was running JBL E140's in them because they had a higher sensitivity than the JBL 2225.

But after a number of people told me the 2225 would work a lot better in the cabinet (even though the sensitivity was lower).

So I bought a 2225 and tried it. It ran circles around the E140 (in the intended passband of the cabinet (below 150hz).

Then I started looking at the specs (limited as they were-especially back then) closer. And I noticed that the E140 (which is a bass guitar speaker) was rated at a higher freq range the the 2225 (which is a sub speaker).

AH HA It was not important to look at the specific freq range.

Exactly what Bennett said.

And a single number tells nothing what the speaker actually does-simply that it will produce that SPL-at some freq. There is one major manufacturer who has a 2x18" sub that has a rating that is really high-and is stated as Sensitivity 20-20Khz. But if you look at their published data-you will see that this peak SPL is around 1800Hz. Not exactly in the sub range.

Just like you have to look at the ACTUAL freq response of a loudspeaker-not just looking at the simple numbers. Look at THE CURVE.

ALSO-different speakers respond differently in different cabinets-especially horn cabinets. In a front loaded cabinet-there is not as much "going on" in terms of how the driver and the cabinet interact.

Not all drivers can be horn loaded.

And yes there are all kinds of situations/products out there in which the cabinet with a lower rating will actually be louder. it depends on how they were measured-and what the marketing dept does to the numbers and so forth.

 

[Chris Van Duker]

Re: lighten up some subs

There is no Danley horn in any Yorkville box.

I thought the Paraline was a DSL technology-- it shows up in a vertical array box by Yorkville, and in the line arrays by their subsidiary VTC.

 

[Ivan Beaver]

Re: lighten up some subs

I thought the Paraline was a DSL technology-- it shows up in a vertical array box by Yorkville, and in the line arrays by their subsidiary VTC.

Yorkville actually built the first Paraline prototype-under Tom Danleys direction-to his specs. It was a test of concept. I think their current products are using a different version-just like the Danley products are using a different version of the same idea.

I will say it again. Yorkville is licensing the technology. Their engineers do the actual design-based on the "guidlines" of the technology.

Tom Danley did not do any of their designs. But he is friends with the guys at Yorkville.

What they (Yorkville) do with the technology is up to them. As with anyting-it is the little things on how it is implemented that often make a difference.

Just like the Unity horn. It is Yorkvilles design of Toms idea-to meet a particular target. If you look at the Yorkville and the Danley designs-you will see qutie a few differences.

The Danley products are different (although using the same "ideas").

 

[Brad Weber]

Re: lighten up some subs

A bit surprised that no one has mentioned that you might want to try to determine what caused the original driver to fail and address that first regardless of what you use for a replacement. If you don't do that, well at least you'll know the process for getting the next replacement.

 

[LiamSmith]

Re: lighten up some subs

I am not entirely certain why the driver failed. However, it seems to have failed in between uses (likely in transport). I'll be cutting the driver out of the gasket tomorrow evening. Hopefully I'll get a good look at the voice coil then.

Anywho, on the update side. I got two lab15's in yesterday. It seems to be an identical gasket. It fit in the cabinet seemingly perfectly. After getting the cabinet back together I tested it up against my other ucs1. They both seem just as sensitive and sound relatively identical.

I'll take some pictures tomorrow of the lab15 next to the ucs1 driver.

I only tested it with about 100 watts through the cabinet. I'll do a full test tomorrow. Is there any way to test for air leakage as a just in case?

 

[LiamSmith]

Re: lighten up some subs


This is the yorkville driver from above


this is the lab15 from above


yorkville driver from below


lab15 from below


yorkville driver profile


lab15 profile

An then I cut out the cone to find the voice coil severed from the cone, yet cleanly. It doesn't look burned or anything. This further leads be to the conclusion that it must have been knocked loose in travel somehow.



(sorry for the blurred photo. Couldn't get a clear one close up)

 

[Tim McCulloch]

Re: lighten up some subs

More likely over-excursion. A dropped cabinet usually results in a de-centered back plate & pole piece, which frequently pinches the VC between the magnet and pole piece.

 

[LiamSmith]

Re: lighten up some subs

If it was over excursion that would be very strange considering the order of events. I tested everything the day before at low volumes. Loaded up the day before. Got to the gig the next day and set up and then tested and found it like this.

 

[Tim McCulloch]

Re: lighten up some subs

If it was over excursion that would be very strange considering the order of events. I tested everything the day before at low volumes. Loaded up the day before. Got to the gig the next day and set up and then tested and found it like this.

I agree that it doesn't make sense for you, but really... speakers die from either a thermal failure or mechanical failure.... and this is clearly mechanical. Can you describe what kind of force would create this kind of *symmetrical* failure? The alternative is adhesive failure, so if there is cone paper on the coil form/adhesive bead, it had to get torn off somehow... and dropping or vibration will not, in my experience, result in the failure mode shown in your pictures.