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Old 3rd July 2007, 10:57 AM   #21
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Quote:
Originally posted by harrygrey382
yeah ok. What about if I ran 2 drivers say. So say two Vintage 30's (In series to keep the the impedance above 8, I don't know whether the amp would handle 4?) against one G12 Century. Which would produce more noise? He does want distortion but says he wants it louder before distortion.

Vintage 30 also comes in a 16 ohm version....
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Old 3rd July 2007, 03:47 PM   #22
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Default dB Sensitivity ; Magnet size ; Tone , etc ...

Quote:
Originally posted by harrygrey382
but as the limiting factor is the 65 amplifier unit, how much louder do you thikn 100 would be? Would he have to go even more sensetive. Also, can anyone comment on the tonal differnece between Blue Marvel and Celestion?
The problem with the Vintage 30 is the power handling is 60w, and 65 can be supplied. Could this be a problem if he cranks it right up?
The Blue Marvel seems to be a version of the older Celestion G12M-70.
It is very likely made from a Celestion specification cone and voice-coil , probably from the same factory as Celestion's own, as likely also is its magnet, and perhaps also its chassis though that could be USA manufactured -{Peavey do not give these details}.
How similar or different I do not know - I would have to hear one of each side-by-side.
The Celestion G12M-70 had a 1 1/2" diameter voice-coil which gave it a slightly more prominent upper-midrange/lower treble response and slightly less bass oomph than their same cone type fitted with their usual 1 3/4" dia. v-coil, -{as was in their G12-65 from similar period}.

The G12T-75 , with 1 3/4" dia. v-coil, sounds similar, but with a little more low-end weight, and some difference in the upper-mids and treble.
Such can make it sound a little louder than a 1 1/2" v-coil version of the same nominal dB Sensitivity rating - noticeable, but not large. The tonal differences will be more noticeable than simply the volume, -{though for some listeners both aural effects combine in their minds}.

The Vintage 30 has a 1 3/4" v-coil, but a significantly larger {and more stronger field] magnet than the G12T-75, though a similar {not identical} cone.
The 50 oz magnet gives it the +3dB Sensitivity increase over the 35 oz magnet models, AND, causes a different Tonal response :-
mainly a tighter bass response, and in general more control over-all, though there is still the typical cone break-up sound in the upper-mids and treble, but the subjective effect is noticeably different.
The 50oz magnet Celestions play slightly cleaner louder before distortion than the 35oz magnet Celestions.

I have heard numerous samples of the magnet alternates, models, and played through some myself.
I prefer the 35 oz, because they are more responsive to finger touch dynamics, though I play with simply guitar through standard valve amplifiers -{Marshall and Fender}- with no Pre-amp overdrive controls/Master volume controls, etc ... and few effects devices.
Other players prefer the response of the 50 oz models, eg: when they want louder clean sound, and use pre-amp overdrive or effects pedals for distortion , etc ... , or for some players it is simply that they use heavier guage guitar strings than I do and often play them with greater force, etc ... {though I do whack 'em sometimes !}.
Note, all I have said is about Tone and Response, as distinct from simply Volume, because unless one likes the tone and response-dynamics the volume means nothing !

I have not played through, and may not have heard a Celestion G12 Century, -{other than used on a recording}, though given its different type of magnet it will have a different sound to the other models.
It will be noticeably louder - as Celestion's dB sensitivity ratings are all to the same scale - but its tone and response I could only guesstimate at and I'd prefer not to.
As you are in the UK, try to hear a G12 Century versus either or both a G12T-75 and a Vintage 30.

As you are worried about the power ratings, then the Celestion "Classic Lead 80" {originally G12-80}, and G12K-100 are both higher powered versions of the 50 oz magnet/1 3/4"v-coil option, and are of the same nominal dB sensitivity as Vintage 30, but with a slightly different cone apparently, thus will sound different to Vintage 30 in mids and treble - more up-front sound judging from my memory of hearing and playing through one of their predecessors.

Once he has decided on tone and response to dynamics of playing, then decide about whether 1 speaker is sufficient, or whether 2 are needed to give the additional volume.

If 2 speakers, then buy 16 ohm versions, as with that Peavey Solid State amp it will probably drive a single 16 ohm speaker OK when he only needs moderate volume, and an extension cabinet with the other 16 ohm speaker can be connected when required.
If uncertain about Impedance capability, do ask Peavey directly, as I do not know exactly how this "TransTube" circuitry of theirs works, though it seems to be responsive to the back-emf generated by the speaker thus the impedance may be relevant.

I would not risk it into 4 ohms .

Extension cab. could be closed back to give a bit more bass oomph, but as closing the cabinet will raise the Fs do make a significantly larger size cab than is the volume of space available to the speaker in the Studio 112 - eg: at least 50% larger, and more if possible.
One way to assist deciding on extension cabinet size is to experiment with how high above the floor he prefers to hear the sound from the in-combo's speaker, then make the ext. cab. sufficiently high to work as a stand, and make it a little deeper front-to-back so as to be steady, as well as that giving it extra internal volume.

Ratio of internal dimensions - height : width : depth - is more critical aurally for closed cabs than for open back cabs.
Make them harmonically unrelated to each other.
I will post more aboput that if you want later, but decide about the speaker type, then the number of first.

Likely if he "cranks it right up" the amp will blow a 60 watt speaker, and even if he doesn't crank it fully but does turn up the bass pot for added oomph it can still damage the speaker - usually such tears the cone at either or both its connection to the voice-coil or connection to the surround, and I have seen one torn from voice-coil out to surround.

If he wants only a single speaker, and still wants bass oomph, then look at another brand for a speaker with at least 120 watt continuous power rating, plus an 80 Hz or lower Fs.
One such is the USA manufactured by Eminence, model - "Texas Heat" - the sample of it I heard sounded good to me, with both weight and body to its sound as well as sufficient upper-mids and treble response similar to the Celestion sounds I like.
1 speaker will never sound like 2 though, simply as sounds coming from 2 different sources give a different aural impression.

Other than its volume limitation, what does he not like about the Peavey "Blue Marvel" ?
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Old 3rd July 2007, 08:48 PM   #23
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wow alan, that's good stuff, I like the idea of an extention, and good point about choosing a similar speaker, we'll look at the the classic lead 80 and will think about buying just a 16ohm version first then think about the extention if there isn't enough volume. We'll ask peavey about how the amp would drive a 16ohm load.

He does like the tone and wants to keep it as similar as possible, but wants more volume even more. Do you think we're barking up the right tree?
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Old 3rd July 2007, 08:51 PM   #24
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oh yeah, and will anywhere give demos for drivers - as in let us bring his own box and head unit and then fit the speaker and give it a play and if it isn't right take it back?
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Old 5th July 2007, 03:51 PM   #25
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Hi harrygrey382 ,

Quote:
Originally posted by harrygrey382


we'll look at the the classic lead 80 and will think about buying just a 16ohm version first then think about the extention if there isn't enough volume. We'll ask peavey about how the amp would drive a 16ohm load.

He does like the tone and wants to keep it as similar as possible, but wants more volume even more.
As he likes the tone and wants to keep it as similar as possible, and have more volume, the obvious solution is to buy 2 Peavey Blue Marvels of that model in 16 ohm.
He will get +6dB increase in volume level as result of the 2nd speaker.
However, as the Peaveys are from the USA this will cost more than Celestions.
Next best option is to look around in advertisments and in shops that take trade-ins/sell 2nd hand for 2 of Celestion's G12M-70 in 16 ohm.
This was a popular seller in its original issue, and the re-issue was only discontinued a couple of years ago, thus there should be plenty around. Guitar players are always selling or trading in for other models.
You may find a pair in a cabinet, thus could use as such, or put 1 in the combo and modify the cabinet to work with 1 speaker, and to stand in which-ever orientation he prefers.

Classic Lead 80 has the larger magnet, and as I described earlier, this changes both the Tone and the response to the player's touch dynamics.
He may not like this if he is used to the response of the G12M-70/Blue Marvel.
He will be different to me, however I find I am able to play a variety of styles well through a 35 oz magnet Celestion, but only a very few well through a 50 oz magnet Celestion.
Some players seem to experience the reverse.
Some like both, albeit for different reasons.

If no good condition G12M-70s to try, the closest alternate is the G12T-75.

If he is buying new speakers, he should play through all 3 of :-
G12T-75 ; Classic Lead 80, or the similar G12K-100 ; G12 Century -{the 102dB Century model, not the Vintage simulating Century as that is significantly lower dB Sensitivity - but he might like its tone and dynamic's response, and 2 of will add +6 dB}.


Quote:
Originally posted by harrygrey382
oh yeah, and will anywhere give demos for drivers - as in let us bring his own box and head unit and then fit the speaker and give it a play and if it isn't right take it back?
I do not know anywhere unfortunately, as I haven't been around the shops for a long time, etc ... , however
there are shops which will have G12T-75s in cabinets,
and will have at least one of the 50 oz magnet Celestion models - even the "Vintage 30" will give him some idea of what it feels like to play through that magnet type.
The Classic Lead 80 has a some-what more forward, or slightly more aggressive, upper-mid & treble than the Vintage 30 -{from my experience of its original predecessor}-, but if he likes the dynamic's response of the Vintage 30 you can then safely order the Classic Lead 80, as he likes the forward upper mids of the Blue Marvel - which I'm fairly sure is basically a Celestion G12M-70 -{I have one of the Peavey predecessor model to that particular Blue Marvel}.

G12T-75 and Vintage 30 are very big sellers, and as Celestion have been heavily promoting the G12 Century, it is highly likely some shops will have those in cabinets, or at least in a 1x12 combo.

Try the shops which specialize in selling to Professional musicians, as staff know that players need to try things.
Similarly, equipment shops that sell 2nd hand instruments and amps know players want to try before buy.
Phone around first to ensure the shop actually has some of what you want to try, if you have to travel some distance, and beware - they may say they can get one in, but may not till they are paid a deposit.
Take his Peavey amp and his familiar guitar - I am presuming the speaker can be unplugged from a socket on the back panel - and ask to plug in a speaker lead to whatever cabinet/s the shop has with the Celestion speaker/s in - even a speaker in a combo can be plugged into another combo if one places the 2 combos back-to-back -{'cos they have such short speaker leads!}.

Other alternate is to phone the places that hire amps and cabinets to professional musos/touring bands.
They may let you try on their premises for a nominal charge, or you may have to hire what-ever for a day - take Identification for security, or they may not hire to you/him.

Look on www.celestion.com under the Guitar Speakers section, and in the left-side column you will see a link titled "Distributors & Dealers".
On that page you will find the option to use to find a Dealer in your area.
If no satisfaction after trying who-ever is listed, then also in that left-side column you will see "Ask Dr Decibel".
This fellow is a knowledgeable enthusiast, thus email to him via the on-site enquiry form and ask who does keep the various speakers in stock for buyers to try - he may know some-one.
Yes, there are the on-site sound samples, but they are only of limited use, as one cannot actually play guitar through them ! , and one would have to play them through an accurate Hi-Fi system, capable at reasonable volume, to hear the tones acurately, and as the samples are all compressed to some degeree, are still not realistic - I did listen to most of them some time ago out of curiosity.
Have a listen to a few of those so that you will know what I mean, and definitely before you contact Dr Decibel so you can tell him you have already tried that option, but need to actually play through the speaker to feel/hear how it responds - he should understand that.

I think I've covered everything ... ?
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Old 7th July 2007, 06:35 PM   #26
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I think originally you were over-thinking the problem. With a guitar amp 'fidelity' isn't a problem, you don't need a ported cabinet and you don't need tweeters.

The frequency response of a typical lead guitar speaker is 70 to 6,000hz, and that is enough. Remember creating music is a completely different animal than re-creating it.

While reasonable application of speaker cabinet design needs to be considered, guitar speakers and speaker cabinets are far more forgiving than Stereo/High-Fidelity speaker designs.

Here are some links to source of specifically guitar speakers. Note the basic spec, and the limited frequency response. Also, notice the relatively high SPL/Sensitivity numbers.

8" Lead Guitar Speakers -
http://www.partsexpress.com/webpage....ctGroup_ID=621

10" Lead Guitar Speakers-
http://www.partsexpress.com/webpage....ctGroup_ID=584

12" Lead Guitar Speakers-
http://www.partsexpress.com/webpage....ctGroup_ID=565

The 'Eminence' are a respected 'work-horse' speaker. Notice they are far more expensive that HiFi speakers. Also, for a beginner Amp/Speaker setup, you don't need Altecs, Cerwin-Vega, JBL, or Celestions speakers. THEY are going to be even more expensive.

Generally, create a box, either open-back, partly open, or closed backed (which I prefer). Make them a reasonable compromise between size necessary for efficiency, and compactness necessary for portability. There are ready-made cabinets of half-stacks ( meaning one cabinet with 4 speakers).

For a beginner, two speakers per cabinet is probably enough.

I don't advise using HiFi speakers, these are two different animals, and HiFi speakers of the same power rating are not going to stand up like the equivalent in musical instrument speakers.

Here is a link to the Fender Instrument Amplifier website, look through the amps and get an idea of what a reasonable size is.

http://www.fender.com/products/searc...iersenclosures

Notice the classic 'Metalhead' Slant Front enclosure on this page. That is the ideal half-stack first speaker cabinet; scaled down for your speakers of course.

http://www.fender.com/products/searc...nclosures&pg=4

The '65 Twin Reverb is a classic Fender Amp/Speaker set up. Many top musicians use this amp. When you need to expand, you just as another speaker 'bottom' to it.

Your daughter might also like the Ultralight Jazzmaster 112 system. (112 means one 12" speaker)

http://www.fender.com/products/searc...tno=2277700000

While good design and common sense still have to be applied, it has to be applied is a different way than HiFi design. In someways, you can play a little more 'fast and loose' with the design rules.

Personally, I would go with a quarter stack for a first speaker system. Say two 10" lead guitar speakers in a reasonable sized cabinet. Two 16 ohm speakers wire in parallel for 8 ohms would allow you to add another quarter-stack later when you daughter is on her way to becoming a rockstar.

Added: Haven't checked it out in detail, but here is a link that might serve as a resource -

DIY Guitar-
http://www.diyguitarist.com/
http://www.diyguitarist.com/GuitarAmps/SpeakerCab.htm


Just one man's opinion.

Steve/BlueWizard
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