choosing 8" or 6.5" midbass

[neon]

i going to build 2-way floorstanders with 8" or 6.5" seas, peerless or vifa driver and can't choose one...(the best for me 8")

so, can u reccomend me something from the list below (only those drivers available in local store)

Peerless

Í×-äèíàìèêè CSC Line
850112

Í×-äèíàìèêè HDS Line
PCA 850490
PCA 850439

Í×-äèíàìèêè CSX Line
PCA 850136


SEAS

6.5"
Àðòèêóë: SS H0352
Àðòèêóë: SS H0416
Àðòèêóë: SS H0419

8"
Àðòèêóë: SS H0333
Àðòèêóë: SS H0397
Àðòèêóë: SS H0282


Vifa

M17SG-09-08
P17WJ-00-08
XG18WH00-08 13007 Vifa
M17SG 09-08 13014 Vifa

[David Gatti]

First narrow down your choice to 6" or 8".
Basically 8" will have beter bass, 6" better midrange and easier to blend with the tweeter. Also depends on size of enclosure you want to build & whether you have a sub. I would recommend a 6 or 7" as 8" usually struggle at the 2-4kHz range.

[David Gatti]

Maybe a 6.5" MTM or MMT is the best option for you.

[neon]

Hi! Thanks!
I'm sorry for bad english!
I want find good result. I don't have sub, and i want a good bass.
How hard co-ordinate 8" loudspeaker with a high-frequency loudspeakers?

Peerless 850490. It's a good choice for 2-way floorstanders?
Or you recommend me other loudspeakers at list(8")?

[neon]

îê. 8".

[jomor]

In brief, 8" cant go up at the middle range as much as the 6.5" drivers thus they re harder to match with the tweeter. If you find a 8" with smooth upper roll-off and a tweeter with low Fs ( below 650Hz),
go for them. You can use a lower x-over frequency and get very decent result. The great advantage of a 8" driver is not the bass, its the fact that it radiates less than the 6.5" towards the sides,
givin less reflections!!! Reflections enhance ( and mess) the midle range about 3db, so you have to consider this when desinging your crossover ( if the speakers will be close to side walls). You can easily leave a maximum 3db "hole" at 1.5-3.5Khz when combining your 8" with the tweeter. This hole will be filled by the side reflections, as long as... you have walls near the speakers.

6.5" radiate stronger towards the sides( compared to a 8"), but they can go higher at the mid area so its easier to match with almost any tweeter.

[JMB]

Actually, as the frequency drops, the likelihood of reflections from sidewalls increases due to increasing wavelength. Reflections are a fact of life and the smaller woofer will have a wider dispersion pattern but this is generally felt to be a good thing to improve off axis uniformity. Room reflections are problematic regardless, and are not likely to be impacted much differently between 6 or 8 inch drivers due to the distance and weakening signal of the wall reflections between the originating signal and the reflected signal. Your brain will likely distinguish the difference. The 6" driver will begin to become directional around 2250 hz while the 8" driver will begin to become directional around 1700 hz. This is not a sudden cutoff but rather a gradual transition. John K wrote a speadsheet that can be accessed in my Speaker Workshop Manual that demonstates driver radiation patterns though you may not want to download the whole 6.5 Mb manual for just this (www.audiodiycentral.com). There is a difference between directivity and imaging, however. Too much directivity will take away from imaging as the speakers begin to sound like a point source. But having greater sound dispersion, stereo speakers overlap their radiation and work in unison to create a soundfield in which you can better identify an overall soundstage with voices and instruments across the stage. Reflections may blur some of the image but also contribute to a sense of spaciousness that is perhaps, less accurate, but more desired by some (hence the success of Bose). The bass response is a function of several issues. The sensitivity of the driver and the frequency response play a role but the amount of air moved (roughly calculated by the size of the piston or driver diamter plus half the surround * the Xmax) is also important.

If you can get an adequate bass response from the small driver for your needs, it may have an added advantage of being able to provide a higher crossover point which will decrease tweeter distortion (IM) and provide the more vulnerable tweeter more protection.

Good luck,

Jay

[usekgb]

I've always been happy with the Vifa P17, or even better the PL17. They are easy to design for, are tolerant of varying box sizes/tunings, and are very affordable. If you don't have much experience, definately go with the Vifa P17 or PL17.

My 2 cents.

Cheers,
Zach

[awboy]

Originally posted by neon
8".

The hds peerless range was/is quite promising but peerless is totally reorganizing and the original hds will disappear.

On your search for a 8" going to 2 kHz: as you can see from the impedance graph the 850490 has problems at 500 Hz already.
Some good results were reported with the older csc217 (850128) which is still available in germany. However, also this cone breaks up at 500 Hz.

I am searching for a good twoway chassis at the moment and I think the HIVI M8N in a closed box may be right.
Or else I will do 2x csx176 bass reflex.

Good luck with your search.

[Cheap Shot]

seas has 8" speaker kit called cygnet MK2 and uses a p21rf/p
that has good off axis at 3k and great off axis at 2k give it a try.
though you'll need a tweeter that can cross over at about 2k !
the kit itself is priced fairly low