Old Mesa Diesel 115 EVM cab... upgradeable?

[agedhorse]

On 06/04/2023 at 12:43, Downunderwonder said:

I seem to recall something about blocking out half the shelf port at the same time.

Which also drops the mechanical power power handling on a driver with already limited power handling.

[Shaggy]

On 09/04/2023 at 01:37, chris_b said:

Hey @Shaggy. . . . that's exactly the rig I had.

 

I started with a Mesa 400+ then went to an Ampeg SVT-3PRO.  Fabulous sound and volume.

 

I also looked at the 1516 but had to say no, I couldn't fit it into my car.

 

 

A man of taste sir! 👍. Beautiful bass too, spoilt only by having one string too many 😉

I did used to gig the 1516 or 2x15 when I had a huge Mondeo estate, but yes the 2x10 plus 1x15 is very much more portable.

[BassmanPaul]

2 hours ago, Shaggy said:

 

A man of taste sir! 👍. Beautiful bass too, spoilt only by having one string too many 😉

I would agree with the first part but to me it has one string too few!

 

[Bill Fitzmaurice]

What I can't do with four strings doesn't need to be done. 😉

[Joebethell]

On 08/04/2023 at 18:30, Shaggy said:

 

Likewise! 🙂. 

With current (not very loud) band I’m now using Ashdown 1x15 and 4x8 mini-cabs with Neo drivers; superbly practical / portable, but just doesn’t move the air in the way the Mesa stack did. 🙁  

Mind, if I had a roadie it’d be the Diesel 1516 every time.....

 

D180 don't see many of them I had a none Eq version at one stage one of those amps I should never have sold. 

[BassmanPaul]

On 12/04/2023 at 16:00, Bill Fitzmaurice said:

What I can't do with four strings doesn't need to be done. 😉

Ah but! I love what my B string can do and the other strings just give me a wider choice of fingerings.

 

[stevie]

The answer to the question is, yes, you could upgrade your cab using a modern driver and achieve a worthwhile performance boost. As good as the EV driver was in its day, it's only rated at 200W and has a relatively modest xmax. You'll need to find out a bit more about the cabinet, however, such as its internal volume and tuning frequency, so that you're not working in the dark and can select the optimum replacement.

Edited April 17, 2023 by stevie

[Jaybeevee]

24 minutes ago, stevie said:

The answer to the question is, yes, you could upgrade your cab using a modern driver and achieve a worthwhile performance boost. As good as the EV driver was in its day, it's only rated at 200W and has a relatively modest xmax. You'll need to find out a bit more about the cabinet, however, such as its internal volume and tuning frequency, so that you're not working in the dark and can select the optimum replacement.

Hei, thanks for this, I have the volume and I see the cab is based on a TL606, but struggle to find the tuning frequency for this cab. And even after that, I actually don't know how to match the drivers. Any tips on that?... this is probably a technical deep dive...

[stevie]

What's the volume? You can test the cab's tuning frequency using the rice-on-the-cone method and a downloadable frequency generator. I did post a link but the forum didn't like it. Do a Google search for loudspeaker rice grain test. Here's an online tone generator: https://www.szynalski.com/tone-generator/

Edited April 17, 2023 by stevie

[DGBass]

These might help. EV mention a specific response for a 3.2cu ft TL606 enclosure and that can't be far of the mark if i recall the size of my old Mesa/Boogie Diesel 1x15 cab. The power rating on that cab was 400watts @ 8 ohms for what that is worth. There may have been a 200 watt version as well.

 

[Bill Fitzmaurice]

It's more likely to have a 15B.

[Jaybeevee]

31 minutes ago, Bill Fitzmaurice said:

It's more likely to have a 15B.

It's a 15L in my cab. Ribbed cone as apposed to smooth.

[stevie]

There's some debate on the forums as to whether the later versions are actually 400W drivers. However, they have a 2.5" coil and even with today's technology a 2.5" coil is normally limited to 300W.

[Jaybeevee]

2 hours ago, stevie said:

What's the volume? You can test the cab's tuning frequency using the rice-on-the-cone method and a downloadable frequency generator. I did post a link but the forum didn't like it. Do a Google search for loudspeaker rice grain test. Here's an online tone generator: https://www.szynalski.com/tone-generator/

Super thanks..

 According to TB...

 

Box Resonance Frequency:
Normal: 55Hz
Step down: 40Hz

 

and a volume of 4,6 Cu ft

[Bill Fitzmaurice]

TL606-606DX%20EDS.pdf

 

1 hour ago, Jaybeevee said:

It's a 15L in my cab. Ribbed cone as apposed to smooth.

Somebody goofed there. The 15B goes lower. The 15L goes higher, but I never found my 15B lacking for highs.

Quote

 According to TB...

Go to the horses mouth. The EDS shows a later version, loaded with the DL15X, a later iteration of the 15B.

Edited April 17, 2023 by Bill Fitzmaurice

[agedhorse]

Most of the Mesa Diesel 115 cabinets were loaded with EVM-15L drivers. This was specifically for the mid voicing.

 

The EVM 15L/B drivers are good for about 200-250 watts RMS mechanically above 50Hz. The series 2 and proline drivers are mechanically the same, the only difference is a coating on the VC which helps bind the coil to the bobbin.
 

The pro line drivers have pretty much the same mechanical power handling as the series 2, the way they were rated changed some.

[Downunderwonder]

Before doing anything else get a high pass filter on the case. That'll let you get a heap of 60hz on your low B without breaking it, by not having to cut bass on the EQ. Night and day difference with vintage gear ime.

[Balcro]

To clarify, in which cabinet are you thinking of installing a new 15" driver? The old MESA or the TL606. There's quite a difference in INTERNAL volume between the two boxes. This EV specsheet shows a TL606 design that is in excess of 85 litres internal volume. Whereas my best guess for the MESA box is around 60 litres.

https://www.realoldiesradio.com/docs/EV/ElectroVoice_TL606.pdf

 

 

 Take a look at the graph below for the EVM 15L (orange line) and reference Bill Fitzmaurice's earlier comment from a few  days ago. I found the T/S parameters from here:-
https://www.manualslib.com/manual/169588/Electro-Voice-Pro-Line-Evm-15l.html?page=4#manual

With a cabinet volume of 60 litres and tuning set to 55Hz as an example that was quoted earlier, the output at 50Hz is down over 11dB! In short, you're quite right. Loud it may be, but it's all in the low mids  200-500Hz. By comparison, it's upper frequency response is only down -3dB @ 1800Hz.

 

If you have the EVM 15B (light blue line), things get better, but only a litttle. There are small improvements in bass volume around the 70 - 220Hz area, so even more thump, otherwise the two speakers are similar up to about 1200Hz from where the "B" output drops away.

https://www.manualslib.com/manual/43648/Electro-Voice-Evm-15b.html

 

 

In short, I suspect you're probably handicapped by the size of the MESA cabinet. 60 litres, if that's the true volume, is today, a bit of an in-between size. Many 15" drivers will still work but prefer 70litres or more to give of their best.

If you consider the Kappalite 15LF into 60 litres (grey line), it's response curve is much like the "B" just as BFM said. However, it's output from 50 -100Hz is beyond the "B".  Lastly, the Kappalite LF into 84 litres (mauve line) and tuning is @ 47Hz.

All inputs set to 150W. All slot ports set to 30cm x 4.7cm. EV speakers set to a system tuning of 55Hz. Kappalite examples tune to 47Hz.

 

 

PS.   ?? 4.6cu.ft = just under 129 litres.

Edited April 18, 2023 by Balcro

[Jaybeevee]

Some great wisdom, guidance and opinions in this thread. I appreciate, but some are a bit above my pay grade..

@balcro To be clear, it's an upgrade to the Mesa cab I am considering. just looking at volumes of the TL drawing you pasted, and a quick calc from the mesa cab dimensions. The TL drawing states 3.2 cu ft which google calculates a to be 90 litres. The Mesa cab Is coming in at 4,5 cu ft which is 127 litres?

A few TB users seem to feel the Kappalite 3015 is a good match, but how to interpret driver specs and consider cab dimensions and baffle design to enable selection of a suitable driver is beyond me.

I played the amp (M6 carbine) through my TKS 1126s and it is awesome.... which confirmed the need to change the driver or move on the Mesa cab. As legendary as it is, I miss the lows (or I am not used to the voicing of the mids). 

 

[Bill Fitzmaurice]

If yours is a 15L then going to a 3015 would give better lows, mainly due to it's longer excursion. At only 3.3mm the EVM is limited to only 100w through much of its range. But don't do the 3015LF, as it is a subwoofer driver that doesn't have much in the mids. It still may be necessary to lower the tuning on the Mesa cab. Given the exact internal dimensions we can calculate what the tuning frequency is now.

[Owen]

3 hours ago, Jaybeevee said:

I played the amp (M6 carbine) through my TKS 1126s and it is awesome....

 

And there is the end of the thread. You spend on messing with the Mesa cab and then you will remember that the TKS 1126 is awesome. Sell the Mesa and buy another TKS 1126. Job done.

[Jaybeevee]

5 minutes ago, Owen said:

And there is the end of the thread. You spend on messing with the Mesa cab and then you will remember that the TKS 1126 is awesome. Sell the Mesa and buy another TKS 1126. Job done.

Almost. In Norway, band generally have a rented rehearsal space with their own gear, and so more with than one band it's useful to have more than one rig. The M6 is a recent purchase to support a new project. The TKS cabs I use with my Thunderfunk. The Mesa cab came to me cheap (and I have another 15 in a TL606 cab which I´ve had for years) and is why I´m at this point now. The M6 as it turns out and no surprise I guess is freakin fantastic and may well end up on top of the TKSs, but either way I need to upgrade the mesa and other 15 cab or move then on, and find me something more suitable. A nice luxury problem.

[Downunderwonder]

Try the two together for giggles. Should have enough low end and might sound good enough for rehearsal purposes.

[agedhorse]

The Diesel is based on the tuning concepts in the TL cabinet, using the EVM-15L for the driver. The internal volume is pretty close to the stock EV recommendation (actually EV recommended a range of internal volumes, a range of porting versus internal volume and thus a range of tunings).

 

In that box, the EVM-15L is good for right about 200 watts RMS down to ~60Hz  and does so with very high sensitivity. 

These were calcs/plots that I did on the Diesel 115 w/ EVM-15L when designing the Subway speakers, in order to understand the legacy products and why they were as successful as they were. In this case, there was very little driver performance left on the table and because of the sensitivity (at the expense of power handling, it's only a 200 watt RMS driver regardless of the 400 watt numbers applied to the proline series), it will generally take about twice the power of most suggested "upgrade" drivers to achieve what this cabinet achieves with 200 watts.  unfortunately both the driver and the box are very heavy which was a non-starter for the new product line.

 

[converse320]

What have you tried driving it with?  I've got an old diesel which sounds average without a beefy amp.