Ushers 8848P's phase plug....know where to Xover?

You picking that up from the 2nd graph?
Cuz the first graph seems ok.

Don't know how the 2nd graph works.

How bad would it sound until I upgrade my crossover I guess?
And prolly tweeters as well later.

How low would I have to go? cuz 1Khz or 1.5Khz seems to me like ridiculously low. I dont think bringing a tweeter down to 1200hz should be considered a solution for any speakers....but I guess it must be tuff to find a good spectrum'd set of speakers.
 
2nd graph - shows a peak in the area you want to cross.

Where you cross also depends on the tweeter you use - many can be crossed below 2k - I use the SEAS 27TBFC/G - Zaph has crossed it as low as 1450 Hz on his BAMTM.

Below 2k is a good place to start - doesn't have to be 1000, 1200, 1500 etc. - maybe 1900. The closer you get to the peak the steeper the filter will need to be, and a notch might be called for also.

Jay_WJ has experience with the 8945p - he may have some input on this and may even model a crossover for you if you let him know what tweeter you intend to use, or just follow his recommendations.

http://www.geocities.com/woove99/Spkrbldg/
 
Are you talking about the peak showing to be hitting 95 DB range going up?

Isn't that a good thing? (to me the newb it seems like it just achieves higher volumes there)

by 2nd Graph I mean the one that has 3 lines plotted with some points in between.

this is my current tweeter..plz dont laff it's temporary. :)

http://digitechstop.com/index.php?main_page=product_info&products_id=3579

Don't things still need to be felt up to like 2000hz?
A tweeter being brought down can't deliver that range properly can it?
 
I extracted the graphs from the site - you want to look at the top one - this is frequency response and impedence; the second graph is a distortion plot.

The orange line is frequency response, the green is impedence. Notice the rising response from about 1500 Hz to 2400 Hz - this, and the ragged area above it, are the where you want to stay out of, thus the lower recommended crossover point and steep filter slope.

I'm not familiar with your tweeter but I can all but guarantee it is a serious mismatch to the Usher. I would highly recommend that if you're going to do a build with the Usher, which is a very high end driver and a good choice, that you consider one of the tweeters in Jay's designs, or at least something in their league.

Here is another site that will be very educational for you:

www.zaphaudio.com
 

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Most definitely.....those tweeters are temporary garbage for the time being sorta to limp me by.

I agree for what I paid for them they can't possibly be a good match.

I'm on a budget...im stretching to go with the Ushers as is.
Just wanted to have something that can deliver good precsence and clarity but still go deep...since Im not going with a seperate sub.

I guess I will have to replace the tweeters and crossovers at a later stage. I would still need to buy 2 more Usher's at this point for the other speaker box. But for now I am going only with 1 pair.

That is one awesome link!!!!!!!!!!!!
 
If you're not going to use a sub the little Ushers will be really challenged. Consider this design by Jay as an alternative:

http://www.geocities.com/woove99/Spkrbldg/RS180_2way/RS180_2way.htm

Vented 7" woofers will give you much greater bass extension, and the Daytons are considerably cheaper than the Ushers. They are a notch below the Ushers but still an extremely high performing and high value driver - I am currently running the 6" Daytons with the SEAS 27TBFC/G tweeters, one of Jay's designs he did for me, and I can attest to their quality. I purchased the Usher 8945ps on Jay's recommendation and will soon be replacing the Daytons.

If you go this route you can put the money you save into good tweeters and the crossover components - you want to build the crossovers exactly as designed.

Think about it - there is no way you will be disappointed at the sound - you can save your money and move up to the Ushers (8945ps) later. Yes get started in this hobby but do a good design your first time out, otherwise you'll be dissatisfied and frustrated and won't be able to afford to fix your problems.

Yes Zaph's site is great - I've gotten a huge chunk of my education from him.
 
My pair of boxes are 1.94 cu. with passive rad. + Xover @ 3000 each currently.

Daytons don't ride that high either.
Want as much low end as I can cuz im a bass head but want to also clear up the muddy midrange and clarity this box needs.

what do u think of:

http://www.partsexpress.com/pdf/297-308.pdf

I was interested in the ushers cuz they fit the box perfectly even tho they're bigger than current 6.5's . Plus the ushers go down low as well.

How much are the tweeters that would need to match the Ushers? and how much to build the crossover for it? What do you think of sound from this match up even tho we're pulling a tweeter down to cover it's "fault"?.... sound like a lot to do for a "faulty" speaker....even more so if they don't end up sounding freakn magnificent.

I know you mentioned beginners stuff and entry level.....but that stage never lasts long with me...before I get hungry for more.... I lack some knowledge but I can hang w/ some guidance when I'm a "newb" at something. But I do go straight to mid-level and or advanced as a routine on things.....cuz I detest doing things twice for lack of knowledge....hence me coming here...and or the internet.

Slowly re-building these speakers around a pair of newly added Usher's is not outside the realm of possibilities...and I think may prove more satisfying when completed...Than having to revisit them later...I would rather do 1 speaker at a time if anything.
Which is what I'm considering.
 
The Vifa woofer is a good choice considering what you intend to work with - it is much better behaved in the region you want to cross over. It is also an overall excellent driver and should give you some decent low end. Both the Dayton and Usher would be a step up, but are not as compatible with your limitations.

It looks as though you intend to use a stock crossover rather than build one more appropriate to particular drivers, at least to start - that's ok for a first build but far from ideal; the Vifa would be the more practical choice here. The cost of building proper crossovers, depending on components, might set you back between $50 and $100 for two speakers for an Usher or Dayton design - IMO a very reasonable, and necessary, part of the overall budget. Again I would rather see you spend a little less on drivers going in and use that saved money for crossover components.

I'm a little concerned that you intend to use a passive radiator with a midbass driver - this is unusual and the results are completely unpredicatble without some measurements. I'd rather see you replace them with small subwoofers - you'd have strong bass without a separate sub and you have enough room in your cabinets to work with. You will want to completely seal off the woofers from the mid-tweet section. This would also allow you to use smaller mids - the Ushers being your first choice.

For tweeter prices look at the Madisound links in Jay's site - the SEAS tweeters start around the mid-high $30s and the Peerless is in the $70s - all reasonable and affordable given their performance. Again my tweeter is the SEAS 27TBFC/G - a tad under $40 and one of the best tweeters at any price - the detail and clarity they produce is amazing.

As for "pulling the tweeter down" to cover the "faults" of the Ushers, Daytons, etc. - these tweeters can do this without issue and there are zillions of 2-way designs out there with these types of crossover points - it's more the rule these days rather than the exception. Just look at the response graphs on Jay's and Zaph's designs - there is no problem - it's largely a matter of proper crossover design, something I cannot overemphasize.

If this sort of thing had issues these guys would not be doing these designs.
 
These are my babies:

http://www.polkaudio.com/homeaudio/products/monitor10

And my attempt is to upgrade them to modern standards.

I've considered maybe running 1 Usher and then the other half a boomy-er deeper 6.5 sub but the truth is they kinda hit hard(maybe not 20's) without a true subby woofer now. And also I have been warned that mixing and not pairing up in a box like this is not recommended and I'm heeding that warning.

I am however open to replacing the front passive for a sub....and maybe port holes out back?....but I am hesitant to open up port up front cuz I happen to love their original cosmetics. It may be possible for me to seal the bottom half from the upper half.
But really it would have to be well well worth the extra work.
It is currently a true 2 way design tuned to deliver good bass.
I'm trying to increase its lower spectrum and move it out of muddish mids/upper mids at the same time.
The original tweeters have been long gone. (prolly blown by me or my brother the 1st time out 20 years ago.)
Aside from cosmetics I have no desire to make them originals or restore them. I aim to truly upgrade/enhance their original spectrum.

Sd if I go with the Ushers(2) I will build the X-over and tweet at the same time. Except I will do each speaker seperately at seperate times.(budget)

The box is tuned for 73hz originally but depending on what driver I choose this frequency goes up or down in the software models.

With the 2 ushers I beleive it goes down to the 50's while enhancing the mid-range probably plenty crispier than ever.
As far as I know what we been talking about isn't too far off from the original design so I think the passive and the driver selections should match up damm good.(definite upgrade from the older drivers which couldn't have been purely subwoofers either)

Like you said I think the X-over is of upmost importance. Thanks for the scoop on pulling tweeters down that far. If it's common practice and the modern move then I'll go with the trend.

I'm not gonna order just yet. Let me know your thoughts.

These Ushers are as big as I can go and should drop right in perfectly. The truncated sides allow them to fit snugly side by side. I've measured cutouts and exterior flange areas. They are truly the maximum of what will fit in stock original locations.(6.5's)

I'm looking at 8845P not 8945P becuz 8845P is truncated flange.
Another factor is they truly outperform any 6.5's by a very good margin. (Or at least from partsexpress.com)

Apreciating your help.
 
Well first I didn't realize that the 88s were also 7"ers - for some reason I thought they were 5s or 6s - then i realized Usher doesn't make anything smaller than a 7.

Then I didn't realize (until re-reading) that you are going to use two per side.

So - an unconvention side-by-side woofer configuration, and I'm sure some here will caution against that - but - it will still work. In this case you may not really need a separate woofer - you might get plenty of bass going ported with the two Ushers. You'd need to seal off the woofer cutout though. Yes you can run the port out the back.

I must ask, given the large investment you are putting into the drivers, is there any way I can talk you out of using your original Polk cabs? A much better design would be to go with a tall, narrow floorstander, MTM for a 2-way or TMM 2.5 way. This is exactly what I will be doing (eventually) with my 8945Ps, and using the 8945As as the .5 woofers, due to a little better bass extension.

If you're going to do this you might as well go all the way, for reasons stated previously. Email me and I'll send you Jay's TMM 2.5-way design - crossover schematic and enclosure. The frequency responses of the two drivers are similar, so you might be able to get away with the same crossover, but the 88 is a different driver with a different cone material so it may have higher distortion than the 89. Jay may be able to offer some crossover tweaks.
 
Well I may have thought at one point that the paper cone could hit higher decibels rather than seeing the graph go higher and thinking it as a sign of distortion.

If thats the case these seem a little more stable and offer the same truncation:
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=296-608

I wouldnt want to block the passive..I like it's sound delivery and it is suppose to function the same as a port....or do u think it is that dated and retro? but yea to have to fiber/putty/whatever that passive hole I would rather trash them...(too much work)

I maybe more willing to convert them to a 3 way design. Replacing the passive with a 10" sub. maybe sealing it and porting it(if suggested) New X-over and dedicated extra crisp midranges that don't require a tweeter to be brought down some. In this case I should be able to use cheaper (but CLEAR) midranges, probably a polk audio DB series sub ($45.00), and a suggested X-over....while still limp by with my current tweeters.

Aside from power distribution which I'm guessing the Xo will handle...I have and still see this as possible. I have Im sure of 100 watts for each speaker without confirming.....it is possible that it could be more like 120 watts cuz the manual says 100 for Canada 120 for other countries. Sony STR DE 345.

The passive bottom end sits right across from the rear mounted crossover. So if I seal this half of the speaker...i take the current crossover with it(sealed off)......shouldn't be a big deal I guess but I will have to wire the upper half before sealing them apart obviously.

I dont think I have the patience to start from scratch on a box or to make good on the outside finish if I completed them....they will sit there and look ugly for a year before I retouch the outside.

I am fond of these boxes tho to be honest. I made more use of them than my dad ever intended to when it was coupled to his entire armada of Denon equipment. His working hours meant I could crank "money for nothing" for hours on end. And god damm they rendered that guitar like as if I was right there on a front row seat.

I saved them from getting trashed....yes maybe to turn them into some Frankenstiened hacked up monsters.....but if they can play beyond what they did in their day....and I can still look at them....it will all be worth it. :devilr:
 
The frequency response graph does not really indicate distortion - a rise in frequency response just needs to be handled in the crossover - it doesn't necessarily mean the speaker is distorting more in that region, although it will certainly sound that way if it is not flattened out.

The 8836 has a wider rise in the FR curve - more like a plateau than a peak, and it's not quite as high as the 8848. You would actually want to start rolling this one off sooner but it probably doesn't need a notch filter.

I'm not an expert at reading distortion plots myself, but if we just go with the overall lower plot it looks like the 8836 would be a better choice (if anybody has better input please chime in!). There are different ways and methods of measuring distortion and there are different arguments for each, but what pleases me about Usher is that they actyally publish their numbers.

So, consider the 8836.

Passive radiators are not "old school" or anything like that - they serve a similar purpose as ports and are used rather often in subwoofers. But they are tricky to get right and you need the right size, weight etc. and really need to be able to do some calculations - just throwing a 10" PR in a cabinet with two 7" midwoofers may be nothing better than a disaster! Yes I'd much rather see you use a subwoofer, sealed or ported.
 
These seem to have some good low end and a flat line upper.....also raving reviews in the comments section.

http://www.partsexpress.com/pdf/297-305.pdf

They seem to be ready to crossover at 3000 as a few ppl have noted in the comments section.(which is what the current crossover is set to do.)

Tell me if u think they would sound night and day difference from the Ushers. Cuz they are farrrr cheaper. So instinctively that means they may not come close to sound quality.

The real kick in the *** is they have a low FS and bring the box FS down to 19.7 in the software models....and since they seem to go up to 3/4K steadily....they maybe a great match.

If I were to go with those I'm guessing I would want to add a quality tweeter sometime soon....then maybe a new crossover or is it possible to rebuild my current ones? or would I get cleaner response from a whole new 2 way crossover?
 
The Ushers will sound better, but "night and day" is subjective - it will boil down to personal preference and I can't make that call for you - for some the difference would be tolerable and for others intolerable. Unfortunately there would be no way of knowing without building with both and doing an A/B comparison.

The Vifas won't sound bad - they will sound very good - excellent actually. Being far cheaper doesn't mean sounding bad - it means that the small increments in sound improvement at the very top end are just that much more costly to design into the driver.

The advantages of the Vifas are as you said - they reach much higher in FR and thus you can use a less expensive (but still good) tweeter to mate them with, with a simpler crossover - so money saved all around.

Looking at the Vifa FR curve I'd say you can get away with using no crossover at all - they remain smooth up high and drop off with little on-axis raggedness - maybe an inductor is all you'll need.

But I'm still confused as to why you seem to be stuck on the 3000 Hz crossover point - it's advantageous as to be out of the human voice range, which many designers use as their "crossover-free" frquency range, but again with good drivers and a properly designed crossover it's not an issue AFAIK.

My friend it is time to make that big decision - ultimately it is up to you. Re-read the thread and try to digest everything we've talked about. Go over your total budget and decide where you want to put the lion's share of your money for now. For us working people there will always be compromises due to the linits of our wallets.

It's time to buy those parts and start building! :smash:

P.S. - always better to go with a crossover designed for the specific drivers, rather than off-the-shelf-or whatever exists in your cabinets - must be factored into the budget.
 
Hey man thanks for all the generous input and knowledge.
I got lost on this paragraph tho:

"But I'm still confused as to why you seem to be stuck on the 3000 Hz crossover point - it's advantageous as to be out of the human voice range, which many designers use as their "crossover-free" frquency range, but again with good drivers and a properly designed crossover it's not an issue AFAIK."

dont know the abreviation and wasnt sure what you were meaning about the 3000 hz being advantageous and the crossover free range.

If I did go with the Vifas I would be considering matching tweeters and if applicable either rebuilding or replacing the current crossover.

I'm not stuck on crossing @3000...im only considering what I have currently.

With whatever crossover points I end up with let me know what you feel is better rebuilding or replacing entirely? If I wouldn't need a different range than the current 3K then I would consider replacing/upgrading it's old components. Unless of course u recommend otherwise or I should need a different crossover point all together.
 
AFAIK means As Far As I Know. Lots of acronyms on the forum! :D

I thought you were "stuck" on the 3k XO point because you were worried about finding a tweeter that could cross lower.

Crossover-free area (no XO in the region) for many is the range of the human voice, something like 100Hz to 1000 or so - maybe 100 is too low. Many people try to use very wide range drivers that do not need to be XO'd in this area, because many claim that since we are so tuned to the voice that we can actually hear anomalies in the crossover if it's within the voices range. I don't know that this is true, and gobs of threads have discussed it.

All I can say is the Vifa is the only woofer you are considering that is compatible with your existing crossover - you will spend the least amount of money going this route, and yes that XO point is just fine. I would not build anything with the Ushers that did not have a tweeter of matching quality and a completely custom crossover - it's just a waste of money not to.

If you go with the Vifas AND build a custom crossover you can probably get away with a very simple one - as I said you can go with no crossover on that woofer at all and still be OK. You WILL need to protect any tweeter with a capacitor at the very minimum, or the low frequencies will cause it to distort and overheat. The result is death or worse.

At this point I honestly recommend using the Vifas, a Vifa tweeter too as they are both decent and cost effective, keep your old crossovers, use a sub in the cabinets if you don't want to seal them, and you're done (for now). Two of the Vifa woofers in each cab plus a port will also give you good bass output (with appropriate cab volume), but again that means sealing the woofer/PR cutout.

This is your first build, with existing cabinets and crossovers - let's keep it as simple and inexpensive as possible.
 
Well as my luck would have it they are sold out of the Vifas.

I have been looking at these as well tho since I had the extra time:
http://www.madisound.com/catalog/product_info.php?products_id=8181

They really seem excellent and have stellar reviews from ppl widely.

I do have a question tho: My amp has 4x- 100 watt channels...the current X-over can handle up to 250 watts per speaker. (another reason the Seas speaker maybe a better match with their higher power rating)

If I want to combine the 2 front and the 2 rears for up to 200 watts per speaker is it possible?

I read somewhere u can take A positive B negative...then short the remaining 2 but am not too enthusiastic to trial run this.......for the obvious reasons. Would I be needing to buy an inverter of some kind to do this successfully?

Hey man merry X-mas!!!!
 
Yes the SEAS is another excellent woofer, though with another one of those troublesome response peaks right where your crossover point is!

As for your amplifier, you are talking about bridging the A & B channels (front +/rear -), and I don't see why you couldn't do that, though I highly doubt you would actually double the output - it's often not that straightforward. You might try to contact the manufacturer and see if they have any feedback about that.

Merry Christmas!