Can An 8" Speaker Cut It Live ?

Discussion in 'Amps and Cabs' started by Electric I, Apr 2, 2015.

  1. Electric I

    Electric I Member

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    Looking at the Quilter MicroPro 200-8 that's equpped with a Celestion TF0818 & wondering how it can hang with acoustic drums in a loud rock band.

    The speaker is rated at 100 watts with a 94dB rating, which seems really inefficient compared to most guitar-centric speakers rated anywhere from 98-102. Wouldn't this inefficiency 'de-rate' the amp's 100 watt output ? Or is the amp rated at 100 watts despite this inefficiency ? I'm guessing the latter, but just wanna make sure I'm not missing anything here.

    Also, the frequency response of the TF0818 is listed as 70-6000Hz. Would this slightly wider-than-average range compensate for it's size as compared to a 10"/12" with regard to low end ? I also read that this speaker has a dispersion of 130 degrees - is that a result of this extended frequency range ?

    Lastly, if one of these Celestion speakers doesn't do the trick, would adding an extension cab with another TF0818 make up the difference ?
     
  2. C-4

    C-4 Member

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  3. little_beetle

    little_beetle Member

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    Hi,

    I think there are a couple of things to consider.

    1) Speaker efficiency. If I am not mistaken, a decrease in 3db is similar to amp power being divided by two. So 94dB is 6dB less than an efficient 100dB speaker. This means that your 100W amp with a 94dB speaker will be as loud (if I do understand well) as a 25W amp with a 100dB speaker.

    2) If I am not mistaken this amp is a solid state amp. The things is that amps are usually rated ‘clean', which means that your amp produces 100 clean Watts. Solid State amps are typically very efficient, which means that their maximum distorted power output is not going to be very far from their maximum clean output. In contrast, tube amps are rather inefficient, so a 100 clean watt tube amp might get to 150W or even more at full overdrive (hence the myth about tube amps being louder than SS amps).

    Anyhow, this all depends on the environment you are playing in. A speaker rated 94dB means 94dB at 1W at 1 m (as far as I recall), so a 100 W that would give about 113/114 dB. Unless you are playing with a jazz drummer, that might be a tad light.

    However, if the amp can be plugged into an external speaker cabinet, you might be able to get something much louder (a 4x12 with efficient 100dB speakers would take you to close to 130dB when full on).
     
    Last edited: Apr 3, 2015
  4. guitarman3001

    guitarman3001 Member

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    Not really, no. I played several gigs with a Bugera V5 which had an 8" speaker in it. The low wattage was only part of the problem. The sound dispersion of an 8" speaker is also fairly narrow.

    What I did was run the amp through a DI box and then through the PA. I would place the amp right behind me so I could use it as a stage monitor and ran it through the PA to fill the room.

    Even a higher wattage amp through an 8" speaker would have to be run through the PA. Personally, I think the guitar should always be run through the PA in 99% of situations anyway, regardless of amp wattage or speaker size or number of speakers, but an 8" speaker will always need to be run through the PA, imo, unless you're playing mellow jazz or elevator music in a room the size of a closet.

    BTW, if you are running the guitar through the PA, any size speaker or amp will work just fine. I've played gigs with a 5 watt SS amp through a 3.5" speaker and by using a DI box and running it through the PA, it worked just fine. And I've played gigs with no amp, just a DI box, and that worked fine too.

    But don't expect to be able to fill a room with just an 8" speaker's stage volume.
     
  5. jazzguitar14

    jazzguitar14 Supporting Member

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    Ive used an Evans AE150 w/ a 8in Eminence Beta for many gigs. Its not the ideal but its certainly loud and good enough for most jobs.
     
  6. BigPapiFan

    BigPapiFan Member

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    Yes. I have seen Oliver Wood play shows with a 5W Fender Champ with an 8" speaker. I have also seen Derek Trucks perform a set with a vintage Champ. With good mic and sound system it can be done.
     
  7. J M Fahey

    J M Fahey Member

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    Reading that frequency response I see that it's a solid performer, and its average SPL is around 95dB ... almost same as a "99/100dB" Eminence

    Basically very similar response at lows and mids , but the Celestion, being a PA speaker, lacks the typical high mids peak (usually around 2500Hz) that most guitar speakers have.

    And which many try to damp with beamblockers, hubcaps, etc.
    So in fact losing it might not be a bad idea after all.

    Just so you can see them yourself, compare Celestion frequency response:

    [​IMG]

    to Eminence Legend 1258:

    [​IMG]

    Impressive for an 8"speaker :eek:

    So in practice lows and mids will be very close (incredible) but the Eminence will have way more "bite" .

    Which might be a good or a bad thing.

    I bet Quilter chose that particular 8" for a host of good reasons and the amp should be quite usable.
    The comparison to an Eminence Beta mentioned above is not far away.

    Now .... fighting a loud drummer?
    Much larger amps have a problem with that, go figure.

    That said, raising it with at least a chair and pointing it slightly up towards players heads should help a lot.

    EDIT:It's also easy to see that by cunningly choosing at what frequency you measure, you can come up with many different sensitivity numbers, that's why I always suggest Musicians to look at the whole curve and not just to a single "raw" number.
     
  8. Electric I

    Electric I Member

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    C-4 : the Laney looks like a great piece of gear, but I'm old school & a traditional cab is the way to go for me. Thanks for that, though.

    little beetle : your math is right & the reason for this thread. Yes - the Quilter is solid state, but by many accounts it's supposedly 'real world' watts & compares with it's tube counterparts in both feel & power ratings. What I'm trying to figure out is if the amp is putting out 100W in spite of the stock speaker rated at 94dB or is that 100W being diminished because of the less-efficient-than-average 94dB speaker. I would hope since the Celestion TF0818 is stock in the MP200, the wattage rating of the amp is taking the speaker into account.

    guitarman3001 : no doubt that ideally, guitar amps are miked for a better blend & dispersion. From what I've read on the MP200 people are saying it's getting the job done - un-miced, no less.

    jazzguitar14 : thanks for weighing in & if I was a jazz player I bet any of the Quilters would be more than suitable and have read words saying as much.

    BigPapiFan : thanks for the examples & no doubt with pros behind the instruments & consoles, just about anything is possible.

    J M Fahey - excellent comparative info & thanks for taking the time dig it up. This is what I'm getting at - folks are saying the 8" Quilters are hanging in live environs & my initial reaction looking at the TF0818 & it's low dB rating is - how is it possible ? Your explanation shows another way of looking at it. I'm guessing the smart man that Pat Quilter is, he has it figured out.

    So what about this scenario - a Quilter Tone Block that's rated at 200W into 2 of the above speakers in order to use all available wattage ? Also, the Tone Block apparently is a 400W amp with 200W 'in reserve' for headroom and/or transients. Wouldn't that make a significant difference ?

    Hmmm...
     
    Last edited: Apr 2, 2015
  9. Mullenski

    Mullenski Gold Supporting Member

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    I play a Swart 6V6se with 8 inch speaker. Mic'd - absolutely! Sounds huge. No mic - as a previous poster mentioned, it's a sound dispersion thing...
     
  10. DaveKS

    DaveKS Member

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    Amps watt rating would be with ohm load presented to the power amp by the speaker, how loudly a speaker presents that in SPL is another story. If you look at that lower ohm tracing in the graph posted above for that little Celestion you'll see that in the lower registers it presents a very low ohms to amp compared to some other speakers.

    In Legend speaker graph you can see it's presenting about a 40ohm load to power amp at 100hz, on that little Celestion at 100hz you can see that it's ohm curve doesn't cross over the response line, looks like it's presenting a a 30ohm load to power amp, that little speaker will have some balls on the bottom end in relation to it relatively small cone size.

    SPL just gives you gauge for apparent vol you can expect out of it, a 8ohm load on power amp is a 8ohm load regardless of SPL any certain speaker is rated at. You have to look at that ohm tracing to get a grasp as to how any certain speaker will perform at a certain HZ.
     
    Last edited: Apr 2, 2015
  11. Electric I

    Electric I Member

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    Mullenski - good to read. From all I've read, Swarts are fine amps.

    DaveKS - even more great insight. Thanks! I never paid attention to the ohms trace before.

    My gut is now telling me that with the right positioning & enough power this speaker is up to the task I'll use it for - jams/rehearsals with a loud but not overbearing rock drummer and adding a mic for live.
     
    Last edited: Apr 2, 2015
  12. griggsterr

    griggsterr Member

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    I own a Quilter Aviator 12, and Have played an 8 inch model several times.
    My perception, it will get plenty loud, but the Quilter also has the best direct out I ever heard so, I would use it as an amp for me to hear well enough onstage then send the direct output to the PA. IF you think that most of the time you will use it without a PA then I would get a bigger speaker, even the larger micropro 12 only weighs maybe 30lbs.
    Loud, yes a Micropro 8 gets plenty loud, but it does lack deep bass response, that a 12 would give you.
     
  13. Mullenski

    Mullenski Gold Supporting Member

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    It's amazing what you get mic'd up; all the feedback, huge crunch, massive leads. With a mic, it's 14 pounds of thunder! So fun!
     
  14. Multicellular

    Multicellular Supporting Member

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    I had an 8" Quilter. It gets very loud. Comparable to a 30 ro 40 watt tube amp. I've played unmiced in front of 75 ish people with it. My issue was dispersion. It was too unidirectional for me. I switched it to an open back cab and was happier.
     
  15. dconeill

    dconeill Member

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    The output wattage of an amplifier is independent of the efficiency of the speaker. Wattage is a measurement of power. A guitar amp of a given power rating will output that much power regardless of what speaker you attach it to.

    If you want to know the comparative output of a guitar amp, look to dB, which among other things is a measure of loudness. Other things being equal, a guitar amp of a given power will produce less loudness if it's attached to an inefficient speaker.
     
  16. Electric I

    Electric I Member

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    Mullenski - no doubt!

    griggster - good to read about the Direct Out. I'm now leaning toward the Tone Block & have read where the DI takes the impedance curve of the speaker into account. That has to make a significant change in how realistic the DI sounds.

    QITD - always good to read about first hand experience. Yours is more testimony on how Quilter watts can compare with tube watts. Far as dispersion goes, not sure if the 8" you played had the Celestion TF0818 in it, but according to the Mach 2 product page this speaker has a dispersion angle of 130 degrees. That seems pretty good, right ? If I do go the Tone Block route, I have a plan to mount it in an open-back cab with the Celestion & use another of the same cab for an extension. Both speakers will allow for the Tone Block's full 200W to be utilized & the 2 cabs can be separated for even wider dispersion.

    dconeill - understood & was just thinking how the 94dB Celestion would diminish the perceived volume as compared to a 100dB speaker (which it would) & wondered if there wasn't a more efficient 8" out there to consider. All in all, Quilter has selected the Celestion TF0818 as their 8" speaker & no doubt for good reason(s), some of them touched on in this thread.

    Thank you all so much for the interesting & enlightening conversation & feel free to keep any insight coming.
     
    Last edited: Apr 3, 2015
  17. mxvin

    mxvin Member

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    if you like the tone you get it from it then why not.
     
  18. dconeill

    dconeill Member

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    The combo as built would be half as loud as the same combo with a speaker with an efficiency of 100 dB, everything else being equal.

    Everything else is, unfortunately, almost never equal. The speaker enclosure would affect the efficiency of the transducer - typically they're more efficient in sealed or ported enclosures than they are in open-backed cabinets.

    I imagine Quilter chose the speaker they did because it was the best compromise of tone quality, frequency response, and output for the size of enclosure they had in mind. But, alas, they didn't invite me to that meeting.
     
  19. J M Fahey

    J M Fahey Member

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    Agree, but the speaker would need 100dB efficiency over all of the frequency response ... a very tall order.

    Many "100dB" speakers simply do not, period,

    At most they have a 100dB peak at 1 kHz and maybe a higher one around 2.5kHz , won't be perceived as "louder" but as "brighter", by the same reason that raising a couple sliders in a graphic EQ is NOT the same as rising the volume pot.
     
  20. Electric I

    Electric I Member

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    mxvin - most certainly.

    dconeill - yes indeed. So many variables involved.

    J M Fahey - thanks again for the great insight.

    All in all, the thought of lugging a heavy, inconsistent tube amp to gigs just isn't appealing any more & so this quest for a light & compact grab-n-go is in order. Quilter seems to be leading the way in this regard & will likely buy one of their iterations at some point. Thanks again, everyone.
     

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