Bass is lacking.

[Iknownothing16]

So I have an old speaker my dad constructed (he built the cabinet) probably about 18 years ago, the components originally were a EV T350 Tweeter, a Speakerlab HD350p (I think, hard to read the letters) midrange horn, and a Speakerlab W1508s 15" woofer with a Speakerlab crossover (model # 141/79). The woofers were punctured so we replaced them with EVX-155s. The Specs on EVX-155 is below:

SPECIFICATIONS

Nominal Basket Diameter<?XML:NAMESPACE PREFIX = O />

15"

Impedance

8 ohms

Long Term Power Handling

600 Watts

Short Term Power Handling

1,200 Watts

Short Term Peak Power Handling

2,400 Watts

Frequency Response

30Hz - 1.8khz

Sensitivity (1W/1m)

98dB

Maximum SPL

122.8dB

Voice Coil Diameter

4" /102 mm

Voice Coil Winding Depth

.8" / 20.3 mm

Reference Efficiency

2.49%

BL Factor

20.4 N/A

Magnet Weight

7.7 lbs. / 3.2 kg.

Even though they should sound great they seem to lack the range that the specifications indicate they have, on the low end. When compared with the Klipsch SP-1s that we have (which also extend down to 30 Hz) they seem to seriously lack performance. I was wondering if anyone had any idea why? (by the way they were hooked up to a Yamaha M-45 Natural Stereo Power Amplifier (250 Watts X 4) or a Pioneer VSX-72TXV Audio/Video Multi-Channel Reciever (130 Watts X 7) when they were tested. The Klipsch SP-1 was hooked up to the Pioneer.

[WMcD]

I would suspect the cabinet might be at fault. Can you descibe it as far as dimensions, vented or not, etc.

The specs say: DC resistance: 5.0 ohms * Frequency range: 30-1,800 Hz * Magnet assembly weight: 272 oz. * Fs: 35.4 Hz * SPL: 98 dB 1W/1m * Vas: 7.77 cu. ft. * Qms: 5.65 * Qes: 0.216 * Qts: 0.208 * Xmax: 6.4 mm * Net weight: 22 lbs. * Dimensions: Overall Diameter: 15.28", Cutout Diameter: 13.9", Mounting Depth: 6.71".

The Qes at Qts are relatively low. It might be considered to be overdamped. This means it is not very floppy and so at low frequencies it does not resonate very much. OTOH the low Qes is indicating a powerful motor which is what is giving it it's high sensitivity of 98 dB.

Gil

[michael hurd]

Hello, I just looked at the parameters of the woofers.What sort of enclosure for the woofers? IE: vented, sealed, horn, etc? The EV has a large voice coil so it can absorb and dissipate a massive amount of power, but the low QTS (.208 ) and the relatively small Vas ( 7.77ft3 ) means that the optimum enclosure is small and that it will not play very low. I am just guessing, never modeled it, but I bet it drops off like a rock below 45hz or so. ( fs is 35.4 hz )

You may be better off with different woofers, help us out and measure the cabinet, we can calculate the internal volume if it is sealed or vented and get something in there that will perform a whole lot better.

[michael hurd]

Darn, William F. Gil is fast, as I was typing it out, he beat me....[] Basically we are saying the same things.

[Iknownothing16]

The cabinet is vented, it measures 36 in. high, 20 in. wide, and 24 in. long. The vent is circular and is three inches tall. There is no filling currently but it had insulation in it before. There are also two small slits just above and below the tweeter, probably 1/4 of an inch tall and and inch or so wide. I plan to fill these in (with wood). I'd put a picture but can't figure out how.

[Iknownothing16]

I was thinking of sealing off the top portion of the cabinet so that the bottom dimensions would be the same (and still ported) except only 20 in. high instead of 36.

[Iknownothing16]

And by the way, these speakers will see some use in DJing and other high-power activities so any other woofers would have to sustain at least 400 Watts Long Term. My dad thought it was a crossover issue, because they sound almost exactly the same as the Speakerlab woofer did. So maybe the Crossover is a high pass crossover and isn't sending all the low frequencies? I have an old pair of Bose Omnivector Model 2 speakers in my room that sound like they have more bass and only go down to 32 Hz.

[michael hurd]

Assuming these are exterior measurments and 3/4 thicknesss with no internal bracing, that works out to 9.130 cubic feet before taking off driver displacement and port displacement. I would guess at about .15 cu ft for the driver, so net would be under 9 cubic feet accounting for the port. The port is 3" tall?? Is this the diameter or the length? If it is the diameter, then I would suggest moving to a larger vent when the woofers are swapped out. Dickason recommends a minimum 6" diameter vent for 15" woofers.

[Iknownothing16]

They are exterior measurements, and there is no internal bracing. The wall is somewhere between 1/2 and 3/4 in. thickness. The port is 3" in diameter, assuming its completely circular (which I'm not so sure it is). Also the other two drivers take a large amount of space, espicially the horn, which is almost the entire length of the cabinet (maybe an inch or so). If anyone has the specifications on the Speakerlab Horn HD350p I can't find them anywhere and would like to know what they are. Thanks for the advice so far. I can return the woofers for several more days so please hurry if you have a better woofer recommendation. (Max Price=$380 or so each. Must handle at least 400 Watts long term and I would like it to have some serious punch if possible)

[michael hurd]

You mentioned that these are for Dj'ing, might I suggest swapping to a more suitable woofer in these cabinets, and modifying the port to suit, then building a bass bin?? Regardless of how much thermal power they can handle, they will be displacement limited. ( meaning once the Xmax is reached, any additional power just results in heat, and no appreciable increase in output )

The Eminence Sigma-Pro 18 models pretty nicely in a vented cabinet of 8 cubic feet, tuned to 35 hz. Even with this driver, 6mm xmax is reached ( in this enclosure ) at around 250 watts input. I would recommend trying out 2 of these, best part is the price. Parts Express sells them for $ 155 and change, and free shipping right now in the lower 48 states.

[TBrennan]

Son, you need to do a little homework.

As has been said you can't just stick a woofer in a box and expect it to work well.

If you've a certain box size then you need to find a woofer that will work well in that volume, note that the venting would probably have to change too. And you have to decide just what "working well" means to you, there are tradeoffs, for instance for a given box volume the more efficient speaker won't go as low as the less efficient. Choices.

There are many free enclosure modeling programs available online, you need to get busy.

The JBL 2226 works very well in 8 cubic foot box, will get you down around 40hz, that's pretty good for an efficient woofer. Handles gobs of power too, 600 watts. Costs about $330.

[michael hurd]

I would seriously not hang that much power on anything that has that short an x-max. As I said before, the x-max is short, the power handling in any application is directly related to the tuning and size and type of enclosure.

[Iknownothing16]

Unfortuanetly 18" Speakers won't fit in the cabinet with the other components (Horn, Tweeter, and Crossover). And Though I could get another cabinet for it if I was going to do that I'd rather just buy a powered sub and I do need something that does work with the cabinet. Unfortuanetly I don't have the money to do that right this minute. I can modify the port though. As I mentioned earlier my dad suggested it was the crossover. Do crossovers limit the low frequencies sent to the woofer? If so would replacing it allow lower frequencies through? We also thought it could be that the woofer might be underpowered, because the low sounds are audible but lack punch. Is 250 Watts not enough to get enough power to overpower the Klipsch SP-1s output? Or could that also be a crossover issue with the crossover not sending enough power to the woofer?

[TBrennan]

Oh don't worry Michael, the 2226 can take it. I've hammered the living Hell out of 'em and know many others that have too. I've had them so loud you could plotz.

Once they run into compression and stop putting out they can still accept much more power, they wick heat away pretty well.

[garymd]

As others have said, those woofers are not going to move much until you get some serious power into them. Swap in something similiar to the K33 and I'll bet you'll hear a world of difference.

I had a similair issue with an enclosed speaker and swapped in a foam surround woofer and it sounded great. You don't want a foam surround with a ported enclosure but you'll need something with more give.

[michael hurd]

Just modeled the Jbl 2226 in an 8 cu ft box, tuned to 35 hz, 6" diameter port, 4" long. Win-ISD shows that excursion is reached at about 150 watts above and below the tuning point, assuming a voice coil temperature rise of 150 degrees C. 116 db @ 35 hz is about the max you can squeak out of this. This however, does not take into effect any other factors such as port compression, etc.

[Iknownothing16]

Do the JBL 2226 Speakers have a lot of punch? Can you feel them? Because it says clean bass in the description and sometimes that means heard but not felt.

[michael hurd]

Unfortuanetly 18" Speakers won't fit in the cabinet with the other components ( sorry, a misunderstanding here.... )

I meant to swap out those EV woofers for other more suitable 15" woofers and modify the tuning of your existing enclosures to suit the particular driver. ( the driver / box combo you have is not really optimum )

Then> build yourself a 16 cubic foot vented enclosure with 2 of the eminence Sigma-Pro 18" tuned to 35 hz. This should get you the low end you desire and also easy on the pocketbook. ( just need another amplifier )[]

[michael hurd]

Tom Brennen, I am sure that the JBL 2226 will handle the power thermally, but mechanically they are limited. I am sure they would probably withstand being plugged directly into a 15 amp wall socket for a while. [] But they make better heaters than reproducers above xmax.

[Iknownothing16]

Sorry speakerbuilding isn't exactly my hobby yet....so I probably have been sounding pretty stupid. Thanks for the advice, and how do you tune it to 35 hz? Also, I have another amplifier (Yamaha) but it puts out 130 Watts X 4. Is this enough? Or would I be better off pairing the Yamaha (250 W X 4) with the Sigma-Pro and leaving the Horn and the Tweeter with the other Yamaha (that puts out 130 W)