DIY TL606 1 x 15 - revisit, alternative plans?

[lowrentdiscographer 7]

Hi,

A long, long time ago (well about 11 years) I built an EV TL606 1 x 15 loaded with an Eminence kappa 450w 8 ohm driver, with help from this forum.

It turned out surprisingly well given I had no idea what I was doing (and still don't) however it turned out very heavy. I built it in MDF.

I'm considering a fresh box, maybe made from 9mm ply to lose a bit of heft, but would like to ask a couple of questions before I go any further...

1) is there a more suitable, freely available cabinet plan for this driver? I researched the driver and the cabinet specs when I built it but part of the driver choice was informed not just by technical (which I'd be lying if I said i really understood) specs but by a bang-for-buck requirement, and the ability to handle "half" of the Hartke LH500 that I was bought to drive it (about 350w at 8 ohm iirc).

2) if I elect to simply rebuild a lighter 606, will it be ok with a straight box with the same internal dimensions or would it need some extra internal bracing?

I'm not sure im going to press ahead with this anyway, and I'm definitely not in the market for a bought boutique or branded cab. I'm not looking for anyone's latest and greatest either, just whether there are anys alternative known, solid, free (or at least cheap) plans that might be better suited to my other kit.

Motivation is that I may have a gig, and the mantra of the fledgling band I'm in, is rehearse with what you'll be using, and ideally I want a little less heft to deal with, but getting spendy is frankly off the cards.

I've seen a few recent threads featuring a BassChat project 12 inch cab, don't suppose there's a 15 inch equivalent?

Thanks in advance...

Steve

 

Edited December 26, 2020 by lowrentdiscographer
Speedy = meant to say speedy...

[Phil Starr 1,031]

Hi, I don't think 9mm is a good idea unless you love complex woodwork as such thin walls with a big cabinet will need a lot of bracing. There are available plans on the Eminence website and there is a probably a small ported cab design there. Go for that, it will have the best power handling and be the lightest cab. If I get time today I'll have a quick look at running the Kappa through the design software and suggest a cab for you that matches your speaker. 

[Phil Starr 1,031]

The Eminence designs I'd go for the medium sized box if you choose one on these to go with Eminence Designer 

Edited December 27, 2020 by Phil Starr

[lowrentdiscographer 7]

44 minutes ago, Phil Starr said:

 If I get time today I'll have a quick look at running the Kappa through the design software and suggest a cab for you that matches your speaker. 

Phil that's awesome but please don't put yourself out - unless you really want to! When I asked for a cab plan I only really meant if someone could say "Matey you want a JoeBloggs123 ..." off the topnotch their head and to be fair I was half expecting to be told to pull my finger out and do more research first...

I'll have a look at the Eminence website now.

Ta.

[Phil Starr 1,031]

Here you go. The EVTL606 is a good design for your speaker. the low end frequency response is in red below. The green line is your speaker in the Basschat Mk 1 cabinet. You can see there is a loss of bass below 100hz by squeezing this 15 into the smaller cabinet, partly compensated for by a 2db bump at aroung 120 Hz which will add a bit of warmth and punch. For comparison the Blue line is the original 12" speaker I used. 

I gigged the BC mk1 (blue line) for a couple of years what I found was that the extended bass response was sometimes a problem, in smaller rooms which equate to the average UK pub the bass was sometimes a bit too overpowering and needed to be rolled off at the lowest frequencies and boosted a bit at 120Hz something your speaker will do naturally in the smaller cab.

rebuilding your TL606 in 12mm ply will save about 8kg but you will need to think about bracing the bigger panels, putting the Kappa into the 50l BassChat mk1 would be feasible if you are happy to lighten your bass sound and will work well in a live band situation. It will be a loud shouty cab though because of the Kappa's huge midrange frequency peak which won't change. I don't think the eminence design has any advantage over the TL606.

Basically you can use the BC design and lose maybe 12Kg total using birch ply or lose a bit less and keep the bigger cab with the extra bass. Remember though that carrying a cab is about size as well as weight, it's easier to get a smaller cab through doors and into your car. Either way you have decent designs available to you so all you have to do is build. The choice is how much bass you want.

 

[lowrentdiscographer 7]

Brighter could work - its not a sound I instinctively like but I've had a thread running in the effects forum where I've been trying to get some cut-through/presence back after acquiring a new bass that was becoming lost in the rock/alternative 4 piece band im playing with.

It looks to me like you've put a lot of effort into this q for me Phil, and on a Sunday morning (in the UK anyways) to boot. So again thanks.

I'll see if I can find the appropriate bc plan on the site and compare that with my existing 606. 8kg saved would be great, 12, well, better by half again!

[Phil Starr 1,031]

Your Kappa is going to be intrinsically bright for bass it has a huge peak in the midrange which is likely to completely dominate the sound of the speaker whatever cab you use. The weight saving depends upon exactly which type of ply you can source and I used a timber merchants site to estimate the savings in mass you might get so treat that as approximate. The speaker calculations take no time as all the Eminence drivers are pre-loaded into WinISD. It took longer to type than to calculate  the cost is that if you do build to put up some pics of the build here to encourage others to have a go.

 

[lowrentdiscographer 7]

25 minutes ago, Phil Starr said:

It took longer to type than to calculate  the cost is that if you do build to put up some pics of the build here to encourage others to have a go.

Oh I will, I do have form...

[Bill Fitzmaurice 835]

2 hours ago, Phil Starr said:

 The speaker calculations take no time as all the Eminence drivers are pre-loaded into WinISD.

Not necessarily. The WinISD driver data base dates to 2004. Drivers introduced after that won't be there. Even those that are there may have incorrect specs. Back in 2004 Eminence had to change their voice coil former supplier, as DuPont stepped away from the Kapton former business. As a result the specs on most of their drivers changed, some slightly, some significantly. At that same point Eminence switched to Klippel Analysis, and remeasured the entire line with it. Over the years as I've modeled with Eminence one by one I replaced all of the old entries with the most recent. As for the TL606, it was a good enough box where first generation T/S designed cabs were concerned, but was obsolete even before EV stopped making the EVM drivers it was designed for.

[Phil Starr 1,031]

34 minutes ago, Bill Fitzmaurice said:

Not necessarily. The WinISD driver data base dates to 2004. Drivers introduced after that won't be there. Even those that are there may have incorrect specs. Back in 2004 Eminence had to change their voice coil former supplier, as DuPont stepped away from the Kapton former business. As a result the specs on most of their drivers changed, some slightly, some significantly. At that same point Eminence switched to Klippel Analysis, and remeasured the entire line with it. Over the years as I've modeled with Eminence one by one I replaced all of the old entries with the most recent. As for the TL606, it was a good enough box where first generation T/S designed cabs were concerned, but was obsolete even before EV stopped making the EVM drivers it was designed for.

Thanks Bill, I had noticed some of the already entered data can be false. I've always entered the parameters manually for my own designs and I didn't check this time. As for the box for the EV it's a 90l cab tuned to 55 or 40Hz I checked both and I'd go for the 55Hz tuning with this speaker. I think Steve has enough to make some choices about which way to go and I'm happy to answer questions and tweak the design as he goes if that's what he wants.

[lowrentdiscographer 7]

13 minutes ago, Phil Starr said:

Thanks Bill, I had noticed some of the already entered data can be false. I've always entered the parameters manually for my own designs and I didn't check this time. As for the box for the EV it's a 90l cab tuned to 55 or 40Hz I checked both and I'd go for the 55Hz tuning with this speaker. I think Steve has enough to make some choices about which way to go and I'm happy to answer questions and tweak the design as he goes if that's what he wants.

Actually, and in that spirit...

The one bit I'm missing is the basschat mk1 plan... is there a files section or similar I should be looking for? Everything I've found so far has been for 12" driver. Or would I need to be doing some conversion work from the 12" design (scary)?

On the 606 I built, I configured the centre port permanently plugged - the 55hz tune is with this port also open?

Edited December 27, 2020 by lowrentdiscographer
I can type, honest, just not on a mobile touch screen...

[Bill Fitzmaurice 835]

22 minutes ago, Phil Starr said:

Thanks Bill, I had noticed some of the already entered data can be false. I've always entered the parameters manually for my own designs and I didn't check this time.

When you get the 'driver data fails integrity check' message it's usually because many data sheets only go to two decimal places, while WinISD goes to three or more. The resulting data may be off, but not by enough to be of any consequence.

With a direct radiating fifteen I prefer 100L, with 40Hz tuning, otherwise you don't take advantage of what a fifteen can do on a low B, and it takes over-excursion down low out of the equation. If you don't do low B then I'd lean towards 50-55 Hz. When designed in the 80s there was no point in going larger with the TL606 when using the recommended low Qes EVM-15L. Other aspects of the TL606 that I haven't employed since the 80s is 3/4 inch construction, cleats in the corners where they're not required, and no panel to panel bracing that is required for maximum strength with minimum weight.

[lowrentdiscographer 7]

Quick update:

I think I'm going to remake a standard 606 cab, from 12mm ply.

If I remake to the same internal dimensions, including port area, this means that the top of the port will be thinner material that on the original plan and in turn the baffle will need to grow in height slightly to compensate, I'm assuming this is no issue?

Also, I intend to build this without all the internal cleats. Currently my plan is simple butt joints, but pinned with dowels added after the joints are made, and silicon sealed. I'm concerned this might not be road-worthy enough?

With respect to bracing - would a couple of braces running top to bottom and side to side, with maybe 4 arranged around the driver radius, from baffle to the back panel, be sufficient?

[RichardH 257]

I would work out how much of a weight saving this would be before going over to 12mm ply. I can't see the slight dimension change you mention making a difference.

The panels will definitely need bracing (adding more timber to the total), and don't forget the weight of the kappa driver will remain the same - so the cab may not end up that much lighter. Poplar ply would be much lighter - in fact 18mm poplar would probably be lighter than 12mm birch. Poplar is softer though and can "ding" without a decent covering - rat fur, tolex or tuffcab (which has the advantage of being easy to touch up if scraped/dinged). 

[Phil Starr 1,031]

11 hours ago, lowrentdiscographer said:

Quick update:

I think I'm going to remake a standard 606 cab, from 12mm ply.

If I remake to the same internal dimensions, including port area, this means that the top of the port will be thinner material that on the original plan and in turn the baffle will need to grow in height slightly to compensate, I'm assuming this is no issue?

Also, I intend to build this without all the internal cleats. Currently my plan is simple butt joints, but pinned with dowels added after the joints are made, and silicon sealed. I'm concerned this might not be road-worthy enough?

With respect to bracing - would a couple of braces running top to bottom and side to side, with maybe 4 arranged around the driver radius, from baffle to the back panel, be sufficient?

If you are going with the 606 cab then some of the panels are quite big and will vibrate, ply is intrinsically more bendy than MDF and also has less internal damping. You'll need to compensate for this by bracing all the panels.Adding dowels to 12mm ply isn't going to add much in the way of strength, if you used 6mm dowel hat only leaves 3mm of plywood either side of the dowel which will weaken the ply. The only reason to use dowels on something so thin is to locate the panels whist the glue sets. It's quite possible to build a cab with plain butt joints and a glue joint will be stronger than the ply but a 12mm glue join isn't inherently very strong simply because the area is so small and the plies in plywood can easily separate. Reinforced butt joints as in your original cab design are stronger and because you can screw them in from the inside make the construction simple as they pull the panels together hold everything square without clamping and increase the glued area. They will also provide some damping of the panels. If your woodwork is competent though and you have good access to clamps whilst the glue sets many cabs have been built without them so this is a decision for you to take.

8 braces are a lot but it depends where they are placed. It is possible to  put them in after the cab has been built, more later about that.

[lowrentdiscographer 7]

In the interest of knowing what we're up against, I thought I'd post a few pics of the current cab.

The build is mdf, the joint reinforcement is pine, all joints are screwed and glued EXCEPT for the back panel which is screws & weatherstrip gasket.

It was lined with roof insulation but I've torn this all out because I was trying to brighten the sound a bit, so that's why it looks a bit scruffy inside.

The speaker cables are soldered at both ends, I might not do that again and use push on connectors.

The black finish on the bottom panel is some sort of rubber sealant - can't remember exactly what it was now. (I think a rebuild would not get lined in the same way, rather I think I'd give the whole interior a coat of automotive underseal?)

The grille is perforated ali.

Weight (according to highly accurate bathroom scales...) is 29.75 kg...

I was lucky when I built this that the guy who ran the saw station at my local B&Q was happy to do whatever cuts were needed, including the thin pieces for the port construction, and I pretty much walked out with a full panel kit. Now they limit the number and minimum sizes of cut, so I will be stuck with a hand-held circular saw and making a saw fence.

 

 

Edited January 3 by lowrentdiscographer
Typos

[Phil Starr 1,031]

The speaker weighs 8kg so this is a really heavy cab. That's MDF for you. you can play with this Large panels | OSB board | MDF board | Plywood | Chipboard | Weight | Calculator (timberpolis.co.uk) ready reckoner  and work out for your self how much lighter just changing the board material will make your cab. MDF is great unless you have to carry it

Change the volume to area and thickness will come up

[lowrentdiscographer 7]

8 minutes ago, Phil Starr said:

The speaker weighs 8kg so this is a really heavy cab. That's MDF for you. you can play with this Large panels | OSB board | MDF board | Plywood | Chipboard | Weight | Calculator (timberpolis.co.uk) ready reckoner  and work out for your self how much lighter just changing the board material will make your cab. MDF is great unless you have to carry it

Change the volume to area and thickness will come up

Thanks Phil I'll have a look.

[Bill Fitzmaurice 835]

2 hours ago, lowrentdiscographer said:

It was lined with roof insulation but I've torn this all out because I was trying to brighten the sound a bit, so that's why it looks a bit scruffy inside.

Roof insulation is the wrong material, but in any event a bare cab interior doesn't brighten the sound, if anything it dulls it. Without damping sound waves reflect off the panels back to the cone, causing peaks and dips, mostly dips, in the midrange response, and if anything a boomy tone in the midbass.

Edited January 3 by Bill Fitzmaurice

[lowrentdiscographer 7]

1 hour ago, Bill Fitzmaurice said:

Roof insulation is the wrong material, but in any event a bare cab interior doesn't brighten the sound, if anything it dulls it. Without damping sound waves reflect off the panels back to the cone, causing peaks and dips, mostly dips, in the midrange response, and if anything a boomy tone in the midbass.

Hi Bill.

The exact material name I can't remember now, it was a wool-type material but it was made from recycled plastic fibres rather than fibreglass, and it's texture was somewhere between fibreglass insulation and cotton wool. 

I think at least one problem with the stuff I used is it might have been just too thick, a couple of inches depth at least, and it filled A LOT of the cab space. When I'd lined the sides, back and top, it was like the driver had it's own little fluffy nest to sit in! (There was a picture of this on my original build thread, but the photos have been lost, both from the thread and my originals).

Because it's taken more than a decade to break the cab out of my house and into a live band situation, I've never had the need to crank up the volume (other than to very occasionally torment the wife or neighbours) and I wondered if maybe it was being strangled (very haphazard layman-ism) somehow by being over-stuffed. It also occurred that thermally insulating a hard working electromagnet/coil/thingy might not be good. So I pulled it all out in the heat of battle. I ultimately believe that the real problem with my sound is simply we play too loud for the rehearsal space - possibly a bigger example of the sound-wave reflections you describe?

I know Bill you have a great deal of experience and produce some very highly regarded designs for various purposes - I gave some consideration to building a pair of your (now discontinued?) Omni 10's as a second build when I finished this first cab, but being as it hasn't really seen the use, there wouldn't have been much point.

I do like (having a cheeky go at) making "stuff" - but I'm not really a gear head or GASser and I've no delusion that I'm any sort of audio engineer (Nor a musician, but that's a different conversation).

It's like the old adage of a little knowledge being dangerous! When you see peeps doing good work on the interweb it's sometimes a bit too easy to convince yourself to jump in and have a go.

My original build requirements were a gig-able high-ish power handling cab for not much outlay, these requirements are not fundamentally different now, with losing a bit of weight being the main one (again, now it's getting frequent use it's biggest shortcoming is ever-more apparent, although it will be less so now tier 4 lockdown is in full effect).

This is a bit of a ramble. Sorry! I guess I'm trying to excuse myself for not knowing exactly what I what or how to do it...

Edited January 3 by lowrentdiscographer
Typos

[Bill Fitzmaurice 835]

You can use too much damping in a ported cab. An inch to inch and and a half is sufficient. I mainly use open cell foam mattress topper, which works better than acoustical egg crate foam at a much lower cost. Omni 10 was replaced by the Jack 10 in my lineup twelve years ago. I feel that if you can't carry on a conversation when in a small rehearsal place it's too loud. If you ask Pete Townshend's opinion on the subject, or any subject, his usual reply will be "sorry mate, I can't hear you!"

[lowrentdiscographer 7]

13 minutes ago, Bill Fitzmaurice said:

You can use too much damping in a ported cab. An inch to inch and and a half is sufficient. I mainly use open cell foam mattress topper, which works better than acoustical egg crate foam at a much lower cost. Omni 10 was replaced by the Jack 10 in my lineup twelve years ago. I feel that if you can't carry on a conversation when in a small rehearsal place it's too loud. If you ask Pete Townshend's opinion on the subject, or any subject, his usual reply will be "sorry mate, I can't hear you!"

I don't disagree. However, (and I made this point in another thread)...

Guitarists.

I'll give mattress topper a whirl in the new build.

Ta

 

Steve

[Bill Fitzmaurice 835]

In semi-defense of guitarists they need to overdrive the speakers for tone. The problem is how loud that's going to be with even a 1x12, let alone anything larger.

[LukeFRC 1,959]

On 02/01/2021 at 12:37, lowrentdiscographer said:

Quick update:

I think I'm going to remake a standard 606 cab, from 12mm ply.

If I remake to the same internal dimensions, including port area, this means that the top of the port will be thinner material that on the original plan and in turn the baffle will need to grow in height slightly to compensate, I'm assuming this is no issue?

Also, I intend to build this without all the internal cleats. Currently my plan is simple butt joints, but pinned with dowels added after the joints are made, and silicon sealed. I'm concerned this might not be road-worthy enough?

With respect to bracing - would a couple of braces running top to bottom and side to side, with maybe 4 arranged around the driver radius, from baffle to the back panel, be sufficient?

@Bill Fitzmaurice can't suggest it... but I can.... 

Look at his designs for cabs. You will need to check if your speaker works for one of the Simplexx range but I would think given the time and materials you will be putting in there's nothing wrong in buying a proven, tested design. 
https://billfitzmaurice.info/Simplexx.html 

For my 2p - by the time I'm buying lightweight ply Ild probably consider buying a new driver and see what existing designs are out there that suit what I'm after...

[lowrentdiscographer 7]

1 hour ago, LukeFRC said:

@Bill Fitzmaurice can't suggest it... but I can.... 

Look at his designs for cabs. You will need to check if your speaker works for one of the Simplexx range but I would think given the time and materials you will be putting in there's nothing wrong in buying a proven, tested design. 
https://billfitzmaurice.info/Simplexx.html 

For my 2p - by the time I'm buying lightweight ply Ild probably consider buying a new driver and see what existing designs are out there that suit what I'm after...

The only thing that stopped me looking deeper at the simplex - I know there is a non-tweeter 1x15 bass cab version in the plan set- is a significant height and width increase over the ev. I've little doubt it would be a great cab, but it would be very tight in it's live-in space.

That said I'm not sure I follow the logic of your 2nd point. Ply cost, even nicer stuff, is nowhere near the cost of ply + posh new driver.

Still, might be worth thinking about some more.