The Metronome

[chrisb]

I think that in his haste to punch the post button, Dave forgot to state that the location, CSA and volume of the port/terminus are among the significant factors in whether a tall skinny enclosure works as a well modeled MLTL would be expected, or accidentally as a BR (perhaps for reasons unknown or overlooked by the designer)

 

[planet10]

I see. This is an awesome forum for learning stuff!

So, what is this speaker? -- dynavoice

It's behavior will be somewhat different than the usual ML-TL as the driver offset is large & the terminus is not at the end. It is still an ML-TL but not optimal. This kind of thing is often done to try to bring the measured performance closer to the BR sim when the designer does not understand ML-TLs.

dave

 

[planet10]

I think that in his haste to punch the post button, Dave forgot to state that the location, CSA and volume of the port/terminus are among the significant factors in whether a tall skinny enclosure works as a well modeled MLTL would be expected, or accidentally as a BR (perhaps for reasons unknown or overlooked by the designer)

All true.

A typical ML-TL will have the terminus at one end and the driver at the other. To minimize the amount of damping required (and get more bass), a driver offset is often employed (about, but not exactly 1/3). To learn more one should start by reading everything on Martin's website.

For some historical background and more projects my TL site. And Bob Brines has (or at least had) some good comments on actual modeling.

dave

 

[Rullknufs]

Dave, do you sell any FE127e?
And will a Metronome with FE127e fit well with my amp?

 

[planet10]

I have the last FE127 in captivity in North America. They are all destined to be FE127eN. EL70/CHR-70 are better suited to your amplifier (or EL70eN or CHR70eN for the tricked out ones -- something you can diy yourself with some practise).

dave

 

[planet10]

Digression into Lotus-land split off
http://www.diyaudio.com/forums/full-range/164832-lotus-chr70-sweden.html

dave

 

[AmadeusMozart]

Have just read through the whole thread. Somewhere there was talk of using the bamboo Tang Band 4" (W4-1320SJ) driver and that it's spec's were close to the FE108eS so it could use the 108 design for the TB.

Shipping costs to our part of the world are quite prohibitive and they have notched up quite a bit last year. I found locally a supplier (advertising on this board) who has the TB W4-1052SD in stock at a very reasonable price.

I have not found a metronome design for this driver and wonder if someone more capable than myself can calculate the numbers for me.

Many thanks in advance, AM.

 

[AmadeusMozart]

Have just read through the whole thread. Somewhere there was talk of using the bamboo Tang Band 4" (W4-1320SJ) driver and that it's spec's were close to the FE108eS so it could use the 108 design for the TB.

Shipping costs to our part of the world are quite prohibitive and they have notched up quite a bit last year. I found locally a supplier (advertising on this board) who has the TB W4-1052SD in stock at a very reasonable price.

I have not found a metronome design for this driver and wonder if someone more capable than myself can calculate the numbers for me.

Many thanks in advance, AM.

Update:

Same supplier informed me that on indent he could supply me with the W4-1320SJ at a very generous (to me) price. I have now ordered these and will be putting them in a metronome designed for the FE108e Sigma and see how I go from there.

AM

 

[theskintman]

XO, BSC etc.

I now have two lovely new FE207eN sitting in boxes (thanks Dave). I am thinking how these would be best crossed over with FE17H when used with the Baffle-Step Compensation circuit. Would the following be correct? (a simple combination of the FE17/R80B and Metronome FE207e BSC circuits):

An externally hosted image should be here but it was not working when we last tested it.

 

[planet10]

i'd connect the tweeter circuit before the BSC. I'd also try the single small cap approach 1st.

dave

 

[Pit Hinder]

Skintman (welcome to the club - we all are),

go and find yourself a bottle of booze before you try that one.
The 17H is a real find for the price, and kiling it with a cheap attenuator...if you find a matched pair of the latter, let us know where.

Some of the Fostex recommended cabinets are nice if you use them with any driver but what they are recommended for (@Scott - 206 in the 208 horn?), but their Xover ideas...no.

 

[chrisb]

and FWIW, after the requisite 200hr heavy-petting driver conditioning period, you might want to try without any BSC at all

 

[Pit Hinder]

Quite the frugal Canadian, ain´t you? Better spend some hours annoying the neighbors than buy expensive parts that become redundant later...

 

[theskintman]

This is exactly the sort of wallet-friendly advice I like

I will try a few caps between the driver and tweeter and see how it goes. Thanks!

 

[Pit Hinder]

Skintman,
experimenting there might have benefits not thought about yet. Half a dozen caps combined (parallel, just add the values) bought cheap can sound nearly as sweet as a superbrand single one bought at boutique price. Don´t tell it to salesmen.

 

[viertelnach8]

CHR70 vs. EL70

I would suggest that your amps are not well suited for the FE126 (for now lets assume the FE126En is going to be close to the FE126e). CHR70 or EL70 are probably better best. I have drawings for EL70 met, and CHR will follow soon. EL70 & CHR70 come packaged 2 to a box.

dave

I wonder if these plans fly around somewhere or if the drivers may work in the same enclosure...?! The golden CHR would look awesome in a Met! And it would save me 40 bucks that I can spend on a good veneer

Thomas

 

[GrahamAshton]

Hi folks,

Am very interested in the metronome design.

Being uk based i've found Wilmslow Audio on the web as a supplier of Fostex FR units and am interested in the FE166en due to its extended LF range,
Have followed the link to the frugal horn metronome table but can only find the FE167 listed. being new to diy speakers i dont know if these are interchangeable. The specks seem similar but sufficiently different to make me think "ask first pay later" n avoid possible disappointment!

Can any one help please? Also are there any other uk suppliers of Fostex speakers? most other web searches seem to throw up foreign suppliers.

Regards G.

 

[planet10]

I wonder if these plans fly around somewhere or if the drivers may work in the same enclosure...?! The golden CHR would look awesome in a Met! And it would save me 40 bucks that I can spend on a good veneer

I think i have numbers in an email for CHR, EL70 certainly does well in a Met.

dave

 

[planet10]

Being uk based i've found Wilmslow Audio on the web as a supplier of Fostex FR units and am interested in the FE166en due to its extended LF range,
Have followed the link to the frugal horn metronome table but can only find the FE167 listed. being new to diy speakers i dont know if these are interchangeable.

FE166En is probably interchangeable with FE166e, but FE167e is a different beast. FE167 probably has greater bass capability in a met.

What kind of amp do you have?

dave

 

[GrahamAshton]

Hi Dave

Thanks for responding. Was worried thatt his thread had gone cold.

I'm currently driving a pair of rogers LS3s with an old n decrepit kenwood amp. however i'm currently in the middle of tda 2050 chip amp project, a test run to see if i remember which end of a soldering iron to get hold of! before embarking upon a gainclone project probably using a rod elliott PCB

Regards G,