6.5 inch v 8 inch drivers for 2 way speaker

What would you use


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I am thinking about a 2 way active speaker and looking for advice on the advantages and disadvantages of using a 6.5 inch v 8 inch driver for the mid range bass unit.

My understanding is that the 6.5 inch will be better for midrange and voice spectrum and not so good for bass whereas the 8 inch driver would be better on the bass but lose out on the midrange and voice.

Any advice and knowledge gratefully received

Thanks

Lee
 
I'm thinking neither of those is true.

I've now had 3 sets of bookshelf speakers with 6.5" woofers and none of them lacked bass. My current set, after some mods, has really good bass, right down to 30hz.

It's been a while since I had larger speakers but I don't recall ever thinking that an 8 inch woofer was weak in the midrange. It is true the crossover point gets a bit lower as drivers get bigger, but that doesn't mean the overall speaker is going to be lacking in any way.

The best I can advise is to pick your drivers carefully, matching efficiency and crossover points as closely as you can.
 

4real

Member
2004-05-27 8:51 pm
Steyl
In general the 6.5" would be the tradeoff between size, bass extenstion and midrange. But I guess in reality it all depends.. You can have a high Xmax 6.5" driver that can make plenty of bass, and you can have an 8" woofer that will have a clean midrange. It will also depend on the tweeter choice. If you can cross lower, 8" becomes might be a good option. In the end it's the total concept that will determine the actual potential of a system.
 

Sangram

Moderator
Paid Member
2002-09-25 11:01 am
India
It all depends on where you're crossing the 'bigger' driver, and to what.

For an 8" the optimum crossover point is approximately 1.3-1.4KHz before beaming is an issue, and for a 6.5" about 1.7-1.8k.

Most standard 1" domes cross at the latter point. Not all will be happy about it, but most will do it albeit with highish distortion.

To cross an 8" driver at 1.4k is tough, as not many tweeters will hit that low of a freq without a lot of distortion. the few that will include some of the SB metal or ceramic domes, maybe their textile Satori dome, and the Peerless HDS silk dome (which now is the Scanspeak 810921).

You could cross to a large mid-dome like Scanspeak has, or to a mid-dome and then a tweeter on top but then it's no longer a 2-way. The largest I've dared to put in a 2-way is the Satori MW19 with the Satori DN-B tweeter. It required a lot of control over the breakup, 6th order acoustic slopes and there's still a bit of directivity mismatch with the crossover at 1.6KHz.

Then again, Seas has the A21 design which uses a 10" woofer and a 1" dome.
 
8 inch is better .Think of all those great BBC derived speakers which use 8 inch drivers.I have owned plenty of good two ways using 6-7 inch woofers including Sonus Faber Cremona Auditor Ms,Dynaudio Contour 1.3 mk2 ,Meniscus Kairos but they all sound a bit congested and sound like they are straining to get the sound out compared to 8 inch alternatives.The only really good one I have heard is the Dynaudio Confidence C1.
 
I am assuming a wide, even horizontal dispersion is considered a good thing... it is by me, but others seem to disagree...

Given that, an 8 inch needs to be crossed low, as was pointed out by Sangram... although I think his limits are a bit on the low (conservative) side. I would be comfortable taking an 8 inch up to 1.6 k with LR4, and a 6.5 inch up to 2k with LR2 and 2.5k with LR4.

With an 8 inch, your choice of suitable tweeters is limited, and they tend to be expensive.

In my opinion, a better option than an 8 inch is a dual 6.5 inch. You get almost as much air volume displacement capability as a 10 inch, but you maintain the good horizontal dispersion of the 6.5
 
There are so many other variables besides the size. You have to look at the alignments and how it will mate with what comes above.

I like both sizes, but our biggest/best have used dual 6.5” (Alpair 12pw) or 7” (CSS SDX7). The former in an ML-TL hit 25 Hz anechoic (modeled F10), the sealed SDX7 10 Hz higher but can be EQed easier. Sealed box also smaller (volume wise).

dave
 

celef

Member
2012-11-26 7:40 pm
i really like the 2-way format and i like mtm best. there are so many good 6.5" drivers out there but they can sound a bit "smallish", by using two in a mtm array the sound transform to something much greater. i have only find a few 8" drivers that is good for a 2-way
 

youknowyou

Member
2014-06-04 1:50 pm
ive had a couple of 6.5 inch based 2 way (amphion one18, dynaudio c1) and 8 inch based (ref 3 a decapo, AN-J lx, graham ls59, shl5+) and now use a 10 inch 2 way (Seas a26)

while 6.5 inch can go quite low, they sound compressed and i find their midrange a bit small sounding.
8 inch starts to give real bass and i feel its a great set of compromise.
my Seas a26 with the 10 inch do good bass and also seem to work with the low xo point by using a 1.5 inch dome tweeter.
I would never go back to any 6.5 inch 2 way as i find they really sound compromised in the bass.
 
, the basic knowledge is the 6 1/2 has better potential of better mids.and the other potential of better bass.the better will driver will be the Victor.lol


I am thinking of active speakers

I suppose that it also comes down to the driver being able to move air.

I am unable to listen at very loud or even loud levels due to my head post stroke. What that comes down to in dB I don’t know but I could test on my iPhone although I don’t know how

My room is 10’ x 10’ and I will be sitting about 6’ away from the speakers

Thanks
 
I am thinking of active speakers

I suppose that it also comes down to the driver being able to move air.

I am unable to listen at very loud or even loud levels due to my head post stroke. What that comes down to in dB I don’t know but I could test on my iPhone although I don’t know how

My room is 10’ x 10’ and I will be sitting about 6’ away from the speakers

Thanks


Eldarvanyar:

A few things that are being tossed around here but perhaps not explicitly explained are the "beaming" of the driver as frequencies increase and the difficulty of getting tweeter to crossover at a low freq. Larger drivers begin to tighten their dispersion pattern at lower freqs than smaller drivers.....that's why they need to cross over at a lower frequency.

...and tweeters should typically be crossed over at least two octaves above their resonant frequency (Fs)...three octaves even better.

Combining the two things above with a wide bandwidth can be a real challenge.....

...So with an 8" woofer crossed at say 1500hz you need to select a tweeter with an Fs around 750Hz or lower...as a crude example. Add to this sensitivity matching, and off axis freq response etc for both drivers.......
 

phase

Member
2004-10-04 11:59 pm
I'd always use 2x5" midwoofers in MTM configuration with a tweeter that can be crossed at 2kHz in room of that size and with that listening distance. Say, 2xSB15NBAC and Seas DXT in MTM.


Focal did something similar only as a 2.5 way:

Shape Twin - Focal | Focal | Listen Beyond

About what I was going to mention; to use dual 6.5” drivers, and a single tweeter.
 
6.5" or 8"

I'd always use 2x5" midwoofers in MTM configuration with a tweeter that can be crossed at 2kHz in room of that size and with that listening distance. Say, 2xSB15NBAC and Seas DXT in MTM.


Focal did something similar only as a 2.5 way:

Shape Twin - Focal | Focal | Listen Beyond

ZVU is right on the money. The OP is in a small room, and is sitting 6" from the speakers. If this isn't going to change, ESPECIALLY since he has hearing issues due to a stroke, why talk about 8", 10" etc?

If he is going to pull these out from the front wall any distance at all, and still maintain his 6' to the speakers, he is going to be close to the rear wall at his sitting position. I'd choose a smaller speaker with great imaging, and possibly a compact sub. I have no particular recommendation because I haven't built small speakers, but have certainly listened to them.

It would be really helpful in posts like this if people would state their conditions/constraints in the original post so recommendations can be tailored towards achieving a reasonable goal. As just a side note, I really enjoyed Patrick Bateman's recent post about why his favorite mid-bass is the B&C 8NDL51, because it established his criteria immediately.

I'm not being critical, just making an observation.
 
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