New driver for Peavey 1x15"?

[Beer of the Bass]

The band I'm playing electric bass with is looking into doing more gigging, so I'm thinking about getting my scruffy valve rig back on the go. I'm using an old Carlsbro CS100 valve head (which is ace!) into an old Peavey 1x15". The cab is currently loaded with a 70s Celestion G15B-100. I've been playing around with WinISD, but I'm unable to find any specs for this driver, so I have no idea whether it's a good choice for this cab or not, or whether I'd get better sensitivity and tone with a more modern driver. The cab sounds good at low volume, but gets a bit woofy and indistinct as the volume is increased.
The cab has an internal volume of 90.5 litres and (as far as I can gather from WinISD) has the port tuned to 50Hz. It's a tubular port, so there would be scope to lengthen or shorten it if necessary. So can anyone with some knowledge recommend a driver which would work well? Since I'm using a 100 watt valve head, sensitivity is probably more important to me than ultra deep bass or huge power handling. Of course, I could always pick up a different cab used, but my budget is pretty limited, and seems like I could get a decent driver more cheaply than a new cab. Any suggestions?

[Mr. Foxen]

Eminence Kappalite 3015, spensive, but happy in that box, and sensitive. If you are only running 100w don't need to worry much about the port either, more power and it wants to be bigger/two of them.

[Bill Fitzmaurice]

[quote name='Mr. Foxen' post='972094' date='Sep 29 2010, 04:20 PM']Eminence Kappalite 3015, spensive, but happy in that box, and sensitive. If you are only running 100w don't need to worry much about the port either, more power and it wants to be bigger/two of them.[/quote]
This is one case where the 3015 might not be right. Low power amps tend to rely on high Qts drivers that give a midbass response bump to get adequate volume, at the expense of low end. The Eminence Beta 15 is one example.

[Mr. Foxen]

I'll have a go with my Carlsbro 60w into a Barefaced Compact tomorrow and see what its like. Shame this isn't in a week or twos time, jsut spoke to Umph and my CS100 is fixed bar some valves.

Beta 15 is cheaper, so that's a plus.

[Phil Starr]

As a temporary and cost free solution you could try blocking the port. It seems possible that the cab was not re-tuned properly when the Celestion was fitted and there is no real loading on the speaker at low frequencies. It is equally likely that a 1970's speaker has a fairly short voice coil and it is simply exceeding it's excursion limits. Either way making a sealed cab might help clean up the bass a bit and it will cost you nothing to try. Putting 100W through a speaker like this is likely to blow it fairly quickly though and you need a new speaker. The beta looks good.

[stevie]

Yes, that Beta is great for recreating the vintage sound of your grandad's radiogram.

[Bill Fitzmaurice]

[quote name='stevie' post='972650' date='Sep 30 2010, 08:28 AM']Yes, that Beta is great for recreating the vintage sound of your grandad's radiogram. [/quote]
Or a Portaflex. Delta 15s are the preferred replacement drivers in the lower powered models, where the 2.7mm xmax is of no concern.

[Beer of the Bass]

Cheers for the suggestions. The price of the Beta is definitely attractive compared to the 3015. So higher Qts is a desirable property in this situation? Is the Delta also worth looking at, or does the bigger Xmax of the Beta make it a better option?
I think I'd rather go with a new driver than keep the Celestion and block the port, as I feel a little wary about how reliable a 40 year old speaker might be when driven by a 100 watt amp.

[Mr. Foxen]

Xmax is for when you have lots of power. Not so much the thing with valve amps.

[Bill Fitzmaurice]

[quote name='Beer of the Bass' post='973104' date='Sep 30 2010, 02:45 PM']Is the Delta also worth looking at, or does the bigger Xmax of the Beta make it a better option?[/quote]The Delta response is smoother, though it has only half the displacement limited power of the Beta. But it still probably has twice the displacement limited power of that Celestion.

[stevie]

[quote name='Beer of the Bass' post='973104' date='Sep 30 2010, 07:45 PM']Cheers for the suggestions. The price of the Beta is definitely attractive compared to the 3015. So higher Qts is a desirable property in this situation? Is the Delta also worth looking at, or does the bigger Xmax of the Beta make it a better option?[/quote]
A high Qts is not desirable at all. On the contrary; it's what you get when you reduce the size of the magnet in an attempt to build a speaker as cheaply as possible. In your cabinet, the Beta will give you one-note bass centred on 100Hz with nothing below that. To see what I'm talking about, go and have a look at the cabinet suggestions for this driver on the Eminence site. The optimum cabinet size for this speaker is around 800 litres, which should tell you something.
When you try to get a little fatness out of your sound by boosting the fundamental, you will have very little power left to do anything else. Trace Elliot get away with that approach (the Trace Elliot contour), but their amps are more powerful than yours.
At the moment, the best specification 15" driver on the UK market is the Fane Sovereign Pro 15-500, which costs about £80. There is also the Fane 15-500, which is cheaper (£68) but doesn't have a cast chassis - which is worth the extra IMO. I know that you don't need the power handling, but high power handling is a characteristic of a good quality driver nowadays. Any of these drivers will be considerably heavier than your Celestion, by the way.
AFIAK, if you pay less than £70 for a new 15" driver it will have been built down to a price.
If you're not in a rush, you could keep your eyes open in the For Sale section here. Used 15" cabinets don't seem to retain their second-hand value as well as others, and there have been some real bargains on here lately for £100 and under.

[Beer of the Bass]

Hi Stevie, have you played a cab with the beta and had a bad experience? I'm open to all suggestions as to what may work for me, but it'd be useful to know where you're coming from. I'm not trying for a flat sounding rig with this setup, so a bit of a mid-bass bump could be acceptable, but then I also don't want something that sounds like an elderly mobile disco cab!
Are there really any cabs I could pick up used for £100 or so that would have better drivers than the mid-range Eminences anyway?

[Phil Starr]

Just thought I'd try to clear up the high Q issue. Q is all about the control of the speaker at resonance. A big magnet will control the speakers oscillations more than a small magnet. Of course it will also control the cone better at other frequencies and transients will be better. A high Q speaker will need a bigger cab and will tend to have a bass hump and any note near that hump will excite the oscillation in that area and sound bassy and wooly or warm and rich depending upon your prejudice. Cheap hi-fi exploits this phenomenon to make them sound bassy but it makes all bass notes sound alike cos your hearing the speaker not the music, hence the one note bass tag. A really low Q speaker gives you extended control of the bass and much better behaviour in a reflex cab but can squash the bass a little and it can roll off at 6dB/octave from quite high up. Because it is controlled a little eq sorts this out.

For most purposes Qts above 0.4 is high and below is low. I wouldn't normally put a speaker with a Q above 0.4 in a reflex cab by choice and I don't think the beta is suitable for a reflex cab. If you go for this solution block the ports, it'll save worrying about tuning.

The advantage of the bass hump in an instrument speaker is obvious; it will make the cab sound bassier and if you combine this with the midrange hump of the beta it will sound quite lively. A bit like switching the loudness control on a cheap hifi and I guess this is why BFM suggested it. The Fane which I've used in a design will be much better behaved and will sound quite 'polite'. With no real midrange hump it probably needs something else with it to help it cut through the mix.

Coincidentally I'm currently messsing around with some 10" Fanes. I built a 4x10 for the 10-275's (big magnets, lowQ)
and then because I had them to hand put the 10-125 (small magnet, highQ) in half the cab, which is partitioned so now I can compare the two speakers and see for myself the effect of the 'one note bass'. It is surprisingly subtle, very distinct on recorded music but certainly none of the rest of the band have noticed me swapping over at gigs where so many other factors affect your sound.

Yeah, you probably can get something better for £100 if you look long enough but the beta is only £50 from Blue Aran and you could also look at the Fane 15-400 with a slightly bigger magnet at £56 or the Eminence Delta at £61

[Bill Fitzmaurice]

[quote name='Phil Starr' post='974909' date='Oct 2 2010, 07:38 AM']The advantage of the bass hump in an instrument speaker is obvious; it will make the cab sound bassier and if you combine this with the midrange hump of the beta it will sound quite lively. A bit like switching the loudness control on a cheap hifi and I guess this is why BFM suggested it.[/quote]
A high Q driver is the last option I'd take if I had plenty of power, but the OP doesn't. He may find a lower Q driver works perfectly well with only 100 watts, but then again, he may not, and I doubt he's inclined to embark on a driver testing regimen. Many users of older lower powered amps have replaced the original drivers with Betas and Deltas and found they work quite well. No surprise that, as the Betas and Deltas have specs very similar to vintage drivers, but with higher excursion.

[Beer of the Bass]

OK, cheers for the input everyone. I think I'm going to go with the Beta or Delta, and embrace the bump. This is kind of a "character" rig, and I'm not going to throw loads of money at it. I actually like the sound of the existing Celestion at rehearsal volumes before the excursion weirdness kicks in, so something with a non-flat response at the low end will probably do the job for me just fine. I like some of the older style hairier bass sounds, as long as there's a bit of upper mid response for articulation.
It helps that I'm not a professional musician who needs to be able to cover any sound or style at the drop of a hat. And for any gigs where I want to be clean and even sounding, I can use my other setup (AI Clarus head and EA Wizzy 10 cab) and let the PA do the heavy lifting...

[stevie]

Beer, if the budget is limited, try for one of these on eBay: [url="http://cgi.ebay.co.uk/CELESTION-TRUVOX-1525e-15-EXTENDED-BASS-SPEAKER-DRIVER-/280566084688?pt=UK_ConElec_SpeakersPASystems_RL&hash=item41530ab450"]http://cgi.ebay.co.uk/CELESTION-TRUVOX-152...=item41530ab450[/url]

The chap is selling two and one of them doesn't have any bids yet, with the auction ending today. They are better than the ones you are considering.

[rptrsn2]

+1 on the emminence 3015,put one in my tvx 115 peavey and it sounds awesome in that cab.

[Beer of the Bass]

If anyone is wondering, I now have an eminence Kappa 15 (not the kappalite version) on the way as it looks to be happy in this cab, and one was going very cheaply on eBay. It doesn't give a midbass bump in this cab and has decent sensitivity. Also, it's apparently the same driver as in the Orange OBC115 cab, which a few players with similar tonal goals to me seem to like.