S.P.Q.R. Model 2

[Harderror]

I would like to offer a new design fpr those interested in building: the S.P.Q.R. Model 2 for the Fostex FE126E. It sims extremely well and looks as though it will be a fantastic build. I, myself will be building within a couple of weeks. If anyone else would like to take the plunge and build let me know. I would be interested in following their progress. This plan and the design contained herein is for private use only. Any commercial use is a violation of copyright law. Thanks everyone!

Tom

 

[Harderror]

Another view of the cabinet.

 

[Harderror]

As you can see, it is quite compact. It should deliver a clean 55 Hz and a very usable 50 Hz. Room gain could take it even lower. It does not need to be corner loaded so that could be a plus for many builders.

 

[Harderror]

Here is the simulation plot. As I said, it hasn't been built yet but it looks promising.

 

[gurley123]

Hmmm...Nice wide baffle. You may not need a BSC. Plus it has that nice Hiro/Sachiko stepped path that should make it a fairly easy build. Kudos Harderror.

I really need to make out a list and prioritize my project schedual. Too many nice things to build .

 

[Harderror]

Hmmm...Nice wide baffle. You may not need a BSC. Plus it has that nice Hiro/Sachiko stepped path that should make it a fairly easy build. Kudos Harderror.

I really need to make out a list and prioritize my project schedual. Too many nice things to build .

Thanks! When designing this enclosure, one of my priorities was a wider baffle. That and a square footprint of modest but not minuscule dimensions. These two design requirements made for a bit of a shoe horn situation. Thanks to Scott, Ron, and GM some of the kinks of this sort of design were worked out.

I can't wait to build it either!

Next design will be a slightly more modest enclosure for the ANS8 than the one I built to begin with. I am hoping for a footprint of 15x15 and a height of no more than 4 feet with a tuning at the fs 37Hz of the driver. Now that will be challenge!

 

[Harderror]

Yikes! A small measurement error on the cut sheet and on the board numbering sheet (boards E and F) has been corrected! Here is the updated plan. Sorry for the problem folks!

Updated Model II plan.
http://www.box.net/shared/1uathoykg4

Tom

 

[gurley123]

Tom,

What do you think about putting a set of Tone Tubby's in your Model II's? Do think it would need a CC change? Or would it get to the point of a complete redesign before the performance was optimized?

Specs for the TT's are here.

 

[Harderror]

Tom,

What do you think about putting a set of Tone Tubby's in your Model II's? Do think it would need a CC change? Or would it get to the point of a complete redesign before the performance was optimized?

Specs for the TT's are here.

Well, I am going to be running some sims tonight on different drivers as there has been some interest in this so I will pop those numbers in as well and post my findings. At the latest, I will get it posted tomorrow.

Tom

 

[Harderror]

Alright, I sat down and did some plots tonight. I am really very surprised by the results. I knew any horn ready driver of around 4.5 inches would work great. What I wasn't ready for was that a few that don't look like they should work, will. They may be a bit bass heavy but that can be dealt with. The Hemptone and the CSS will all work reasonably well. With a bit of work the bass can be tamed and you should a have a fine sounding system. The Pioneer looks like it will work without any work at all! Not bad for an 11 dollar driver. Having had experience with this driver, after a good deal of tweaking, it can be passable and even enjoyable. So, there you go. The Model II will work with any number of drivers.

All that being said. The Fostex FE127E looks like it is a no go. I tested one other that was a no go but I did not include it. The Hemp Acoustics FR4.5c. It, like the fe127e just won't comply with the design which is understandable.

Good luck everyone. I hope some more of you will be interested in this enclosure now that you have some choices of driver. Obviously it was designed with the FE126E and the FE108 Sigma in mind but others will work, so...


Tom

 

[Harderror]

So, after reading the best 4" driver thread I thought: "I am going to test the Tang Band 4" Bamboo!" I have always been interested in the driver but have not purchased a set as of yet. I think I will now. I am super impressed with its response in the Model II. Here you go!

Tom

 

[planet10]

All that being said. The Fostex FE127E looks like it is a no go. I tested one other that was a no go but I did not include it. The Hemp Acoustics FR4.5c. It, like the fe127e just won't comply with the design which is understandable.

The published spec for the FR4,5c do not jive with actual measures. Pusblished is close to FE127 spec, measured is about half-way between FE126 and FE127.

dave

 

[Harderror]

So the Hemp acoustics may work a bit better in the enclosure? That is reassuring. I would love to hear from someone that is interested in using this driver in this enclosure. Thanks Dave!

BTW, does anyone have the actual measured specs on this driver? That would be great if they could send them to me. Thanks again!

Tom

 

[gurley123]

Thanks a lot Tom. Now even if I don't use the Tone Tubbies, I could still use a number of other drivers with it. Now I'm running out of excuses not to build them BTW, what kind of things would be helpful in taming the bass?

The pio's are interesting. I was thinking of getting some to be mod mules. Tweek 'em and see what happens. I'll get two(or more) sets and leave a pair stock to track the progress.

 

[Harderror]

Thanks a lot Tom. Now even if I don't use the Tone Tubbies, I could still use a number of other drivers with it. Now I'm running out of excuses not to build them BTW, what kind of things would be helpful in taming the bass?

The pio's are interesting. I was thinking of getting some to be mod mules. Tweek 'em and see what happens. I'll get two(or more) sets and leave a pair stock to track the progress.

I will look at some calcs but there are a few ways to go about it. I am going to try altering the back chamber volume with wedges. I am even considering trying hi density foam wedges as they will not reflect sound so readily and will be easy to get just the right size and shape. and should flatten things a bit. Altering the throat size can do similar things as well but that is one to be very careful with. I need to be careful not to lose the micro-dynamics in the process. Once I have a set built I will begin posting what I am doing with other drivers. I am going to pick up a pair of 108 Sigmas first and then I am really interested in the TB Bamboo so that may be next. I have the old Pioneers here as well so I will mess with those. Thes hemptones, I have no experience with them so they may be worth a look.

On an alternate note. This past weekend, my preamp went and took my amp and almost my Audio Nirvanas in the Model I with it. I guess that is the price for not enough surge protection as it was cause by a lightning strike directly to my house.

The lighter side to the story is that to replace my pre and solid state amp, I bought the Cambridge Azur 540a Version II. (this replaces the Azur 340 A). I am still running it in as it just came today, but, I have to say, it sounds better than the 340a and is really very impressive for a sub $1500 dollar amp (super sub being $420). Not too shabby. One thing to take in to account if anyone else is interested in this amp or any of the Cambridge line, let it run in before you make any judgment on it. I started running it in 4 hours ago, and though it sounds superb now and will only get better (it usually takes 100 hours to run in the cambridge gear) it sounded atrocious initially. If I was to make a judgment on the first hour, I would have sent it back. As it stands now, it sounds smooth and very tube like with the immediacy of solid state. It is getting better by the hour too.

Anyway, a good end to a bad story.

Oh, I almost forgot, my 300B amp went with it too. Fried the chokes which in turn took the tubes and I believe half the caps and resistors with it, as well as the output transformers. Ah well. Now, I just need to decide whether I want to build a new amp (I am enamored by the Darling and am seriously considering a high quality incarnation) or rebuild my old Dynaco ST70 in SET mode or maybe one of Nelson's amps. I really do want another tube amp though. Ah well.

Evening all!

Tom

 

[gurley123]

RE: New Amps

Ouch! Sorry to hear that. My fathers house was hit by lightning once. Luckily nothing was hurt. In fact he gave me an old Technics receiver that was plugged in at the time. He swore it sounded better after being hit(do NOT attempt this tweek )

If you have any money left over from your recovery, maybe you could start playing around with some of the nice sounding digital amps floating around. ChrisB and others have been impressed with the Kingrex T20. I love my Gen II Sonic Impact and I'm gonna purchase and mod that Sure Electronics Tripath board. Good sounds on the cheap. What could be better?

Back on topic. Looks like I'm going to try out the Model II with my Hemptones. I can't measure anything except with my ears but I'd be happy to offer any feedback your looking for.

 

[Harderror]

Funny you should mention the T-amp. I still have my super modified SI T-Amp. I am very pleased with it! More bang for the buck than any amp I have ever had. Good stuff. I completely recased, recaped, reinducted and re power supplied. Good stuff. Yeah, in fact that was what I was listening to all week until my new amp came today. I have pictures of it on the forum here somewhere. I used a rat shack box to put it all in. Total sleeper. Looked good though.

Tom

 

[mightym]

A11's in S.P.Q.R. II

Tom,

After the lashing I got for daring to suggest the A11 in the FH, I have to admit that I still do not completely understand ( nor am I sure I care, to be truthful ) why the cheap'lil booger won't work. I am willing to, as the say " take their word".

Now, onward and upward....

Some questions/comments reguarding your new cab designs

"Whut duz ES. PEE.KuhUU. ARR. stand for?

Seriously, the connection (Compression?) chamber directly behind the driver on the plan shows a vertical dimension of only 4.25". Some of the drivers shown on your Sim. plots are 4.5" drivers. Nearly every plan I look at shows chamfering the back side of the driver cutout to allow the driver to " breathe ". Is this an oversight or some deep dark speaker design alchemy?

As I am still looking for an inexpensive plan/driver combo ( though I haven't given up on the FH's, I am now also considering the Metronomes, and even some of the Changs. I do not wish to step on toes, just get equipment which will please me, for little $ as possible. ).

I have Two + sheets of the plywood .5" ( less 1/64th ). If I were to build S.P.Q.R. II's How drastic would the effect of the thinner ply be on this. I could double panels as necessary to reinforce .... My personal preference in constructing would be to make a reversible template for my router first, and dado the inside of both side panels, then glue/clamp assembly in one go. I would rather have more surface area in the joints than just simple butt joints.

These cabinets also address another of my concerns, that being sensitivity to placement. What do you estimate the best placement would be? what is your estimation of how these will image?

Another bit on the plan, what is the radius of the opening cutout for the horn exit, at the bottom of the side panels. What is the 17 & 7/16" measurement at the very top of the plan?

I am sure I'll think of something else right after I post this.......

All for now, and Thanks.

John B.

Ps Now I remember (doh), your comments Re: the Pioneer, were that it might be bass heavy, I recognize that they are limited in their extension on top ( hence my suggestion of a peizo tweet in the other thread ). What did you have in mind to alleviate ( tighten up ?? ) the aforementioned bass, and what would you recommend in terms of "Tweeks" for that driver ( I'm thinking dammar, maybe EnABL, possibly a Phase plug????

Thanks again.

Pps Hobe ur flu is bedder.

 

[Nikolas Ojala]

May I suggest something...

I guess that the drawing tells more than words.

 

[ScottG]

This plan and the design contained herein is for private use only. Any commercial use is a violation of copyright law. Thanks everyone!

Tom

Umm, not to bum you out, but a copyright does not protect the underlying design you have published here. It does however protect the digital image (which is an "expression" of that idea).