Oh, no! A swapping speaker driver thread!!!

[Bill Fitzmaurice]

The description '6.5" 4 Ohm Hi-Fi Speaker Driver' confirms it's not a musical instrument driver. It's main shortcoming is that it won't have the durability of a musical instrument speaker that's designed to handle high level transient peaks.

 

[Phil Starr]

Bill's right, the other problem is the nature of the suspension, in an instrument speaker the suspension is likely to be progressive stopping the cone from leaving the magnetic gap. The roll surround will be designed for linearity. I've had a look at WinISD and this is the frequency response. I've assumed 9l for the cab volume the same as mine. The green plot is the Fane and the red the Farnell/Monacor.

You get a lot more deep bass out of the hi fi speaker and it's flatter in response, what isn't shown here is that below 50Hz and with just 20W input it exceeds the excursion limits by a lot and this would lead to failure of the speaker in short order without an HPF. this isn't a problem with the Fane (or the other PA/bass drivers) I'm guessing that's why they rate it at 35W

The Monacor is probably going to sound fine and will be an improvement on what you have which won't handle bass either but i don't think it will last long if you play it at any volume. £28 isn't much more than a set of strings so I'd still go for the Fane.

[Pea Turgh]

What a great forum this is!  Thanks Phil!  And Bill!

[Pea Turgh]

Just ordered the Fane 👍🏻

[Phil Starr]

Hope you love it, I'm quite loving the clarity I get out of mine. good for practice because it shows off your mistakes. Ouch!

[Pea Turgh]

Need to get round to replacing the 12” driver in my Peterson combo, too.  It had one of those EV 12Ls that guitarists love.  I wasn’t that bothered, so I sold the driver, intending to replace it with something a lot lighter.

[agedhorse]

On 17/11/2020 at 09:40, Phil Starr said:

Bill's right, the other problem is the nature of the suspension, in an instrument speaker the suspension is likely to be progressive stopping the cone from leaving the magnetic gap. The roll surround will be designed for linearity. I've had a look at WinISD and this is the frequency response. I've assumed 9l for the cab volume the same as mine. The green plot is the Fane and the red the Farnell/Monacor.

You get a lot more deep bass out of the hi fi speaker and it's flatter in response, what isn't shown here is that below 50Hz and with just 20W input it exceeds the excursion limits by a lot and this would lead to failure of the speaker in short order without an HPF. this isn't a problem with the Fane (or the other PA/bass drivers) I'm guessing that's why they rate it at 35W

The Monacor is probably going to sound fine and will be an improvement on what you have which won't handle bass either but i don't think it will last long if you play it at any volume. £28 isn't much more than a set of strings so I'd still go for the Fane.

IF the cabinet tuning resulted in the same curve shape (translated to filter terms this would be Q and slope) than the red trace has the potential to provide better performance with both tuned to slightly under critically damped. Now the elephant in the room is what the relative sensitivities are between those two drivers (which would be the gain term of the filter equation). Is the red driver significantly lower sensitivity than the green driver by chance?

[Phil Starr]

51 minutes ago, agedhorse said:

IF the cabinet tuning resulted in the same curve shape (translated to filter terms this would be Q and slope) than the red trace has the potential to provide better performance with both tuned to slightly under critically damped. Now the elephant in the room is what the relative sensitivities are between those two drivers (which would be the gain term of the filter equation). Is the red driver significantly lower sensitivity than the green driver by chance?

I didn't save the data so this is from memory, which may of course be faulty.

I agree with you about the potential 'better' performance from the red speaker. That's certainly a cleaner curve and showing 'better' damping of the hi-fi driver. Resonant frequency is lower as you would expect with a slightly heavier cone and a less stiff suspension. The sensitivity was very similar if I remember correctly, at the expense of lower excursion limits. I've met PeaTurgh and he says in this thread some of this stuff goes beyond him so I made the assumption what he wanted was a practical solution and a fun project rather than an extensive breakdown of options. I was concerned about the excessive excursion below 50Hz but wanted to show him the frequency plots so he could see the gains the hi-fi drive potentially offered for himself and ask about that if he wanted to and all of this is there in what I've said. I must admit I had reservations about recommending a £12 speaker with potential reliability issues against a speaker I had actually in a similar cab in my room in front of me. I pm'd him with a recording of my bass through the cab to see if he was happy with the sound I was getting. I'd deliberately tailored the response of my own cab and it wouldn't necessarily suit him.

So yes, this was a recommendation based upon practicality. I quite like my little practice amp. the lack of bass means it doesn't annoy my neighbours, the 2db hump at 120hz gives it a gentle suggestion of bass and it sounds OK just plugged and played. Above that it's nice and clean, revealing enough to show up my every mistake which is what I need for practice. Unlike the cheap beginners amp it started out as it now sounds like a bass. The Monacor speaker would probably have sounded great with noticeable extra bass and probably survived quiet practice but i couldn't really recommend something that I thought might not be reliable long term.

[Pea Turgh]

10 hours ago, Phil Starr said:

I've met PeaTurgh

... and he is a clown who needs simple crayon drawings to explain things 🤣🤣🤣🤣🤣🤣

A driver-sized box arrived this morning, so all will be revealed later!

[Phil Starr]

1 hour ago, Pea Turgh said:

... and he is a clown who needs simple crayon drawings to explain things 🤣🤣🤣🤣🤣🤣

A driver-sized box arrived this morning, so all will be revealed later!

you've heard my bass playing, I'm saying nothing

 

[Pea Turgh]

Ok, so progress has been slowed by possible Covid infection - been sleeping most of the weekend!

However, the transplant is done and I am very happy with the results!  I’ve made a video demonstration, but you really need headphones to appreciate the difference - you can’t hear it through phone speakers at all.

I still need to put some wadding in there, and I do wonder if the ports could be improved.  Need to play it in now.

 

[Pea Turgh]

One thing I forgot to mention was that I EQ’d the amp to make it as good as possible with the standard driver, and didn’t touch the settings when recording it with the Fane driver.  With a bit of twiddling, it sounds better again.

Edited November 30, 2020 by Pea Turgh

[Balcro]

48 minutes ago, Pea Turgh said:

One thing I forgot to mention was that I EQ’d the amp to make it as good as possible with the standard driver, and didn’t touch the settings when recording it with the Fane driver.  With a bit of twiddling, it sounds better again.

That calls for another video and test. Nice video work.

 

[Phil Starr]

I do like a happy ending, and yes good video too.

If you measure up the inside of the cab and the diameter of those holes I'm happy to do the calculations for you, I may even have some port tubing the right size I can post.

Hope you feel better soon.

 

Edited November 30, 2020 by Phil Starr

[stevie]

 I can see (hear) why you wanted to change the driver. That's much better!

[Pea Turgh]

40 minutes ago, Phil Starr said:

If you measure up the inside of the cab and the diameter of those holes I'm happy to do the calculations for you, I may even have some port tubing the right size I can post.

 Ooh, lovely!  12cm x 30cm x 23.3cm, and 2x 4cm holes for ports.

Thanks again, Phil 👍🏻

[Phil Starr]

OK I'd go for two tubes 6.5cm long which will give you a little bass lift at 120 Hz. Not real bass but it will make things sound just a touch punchier/warmer. That speaker actually models just a little better in your cab than mine

[Phil Starr]

Oh forgot to say the only 4cm tube I have to hand is the liner of a toilet roll, I'm sure you have them at home  ? if not you might find a round shampoo bottle the right size. Cardboard is quite a good material for a port if it is thick enough. you can stiffen it up with papier mache, (soak newspaper in watered down glue and wrap it round the outside).

[Pea Turgh]

This is bringing me much joy!  I have found some tubing to use for the ports, and still on the hunt around the house for wadding.

Ive also taken the SubZero plate off the front and painted it metallic black, upon which will go my “Pea Turgh” transfer that didn’t get used on my last bitsa.  OTT, but fun 😁

[Phil Starr]

I quite like carpet felt but it is heavy. You'll find most pillows and Duvets are packed with polyester wadding which is also sold for speakers.  Don't let it cover the ports.

[agedhorse]

What about that "fur" thing that's draped on the back of your couch (chesterfield?) That looks like it will work...

Edited December 2, 2020 by agedhorse

[Pea Turgh]

That would be exactly the sort of thing I’d do, just to know the inside would be sooo fluffy!

Unfortunately, Mrs Turgh would remove parts of my anatomy with a rusty spoon if I were to interfere with her carefully styled room!

[agedhorse]

Speaking of fur and such, going back decades acousticians used to refer to sound absorption or anti-reflection as "dead cats". If you needed to reduce the reverb time, you would stick some more "dead cats" on the walls. Not a very PC way to describe it though.

[Woodinblack]

57 minutes ago, agedhorse said:

 If you needed to reduce the reverb time, you would stick some more "dead cats" on the walls. Not a very PC way to describe it though.

Works for me

 

[Pea Turgh]

Not an update as such, but my son re-edited the video.  Looks absolutely ace!